External surfaces of cells are normally protected by extracellular superoxide dismutase, <em>SOD</em><em>3</em>, which binds to polyanions such as heparan sulfate. We constructed a fusion gene encoding a chimeric <em>SOD</em> consisting of the mature human mitochondrial <em>SOD</em>2 plus the COOH-terminal 26-amino acid heparin-binding "tail" from <em>SOD</em><em>3</em>. This tail is responsible for the enzyme's affinity for endothelial surfaces. The fusion gene was expressed in Escherichia coli, and the fully active enzyme <em>SOD</em>2/<em>3</em> was purified. Although native <em>SOD</em>2 has no affinity for heparin, <em>SOD</em>2/<em>3</em> binds to a heparin-agarose column. In a rat model of acute lung injury induced by intratracheal instillation of IL-1, <em>SOD</em>2/<em>3</em>, <em>SOD</em>2, and denatured <em>SOD</em>2/<em>3</em> showed 92%, 1<em>3</em>.8%, and 0% reduction of lung leak, respectively. Only <em>SOD</em>2/<em>3</em> prevented neutrophil accumulation. In the carrageenan-induced foot edema model in the rat, <em>SOD</em>2/<em>3</em> reduced edema by 62% (P < 0.00<em>3</em>) at a dose in which native <em>SOD</em>2 produced no significant effect. Thus <em>SOD</em>2/<em>3</em> appears to have properties as a therapeutic anti-inflammatory agent that are greatly superior to other available forms of the enzyme.

Aging is an independent risk factor for cardiovascular disease, but mechanisms leading to vascular dysfunction have not been fully elucidated. Recent studies suggest that oxidative stress may increase in blood vessels during aging. Levels of superoxide are influenced by the activity of <em>SODs</em>. The goal of this study was to examine the effect of extracellular superoxide dismutase (ECSOD) on superoxide levels and vascular function in an animal model of aging. Aortas from young (4-8 mo old) and old (29-<em>3</em>1 mo old) Fischer <em>3</em>44 rats were examined in vitro. Relaxation of aorta to ACh was impaired in old rats compared with young rats; e.g., <em>3</em> muM ACh produced 57 +/- 4% (mean +/- SE) and 84 +/- 2% relaxation in old and young rats, respectively (P < 0.0001). Three days after gene transfer of adenovirus expressing human ECSOD (AdECSOD), the response to ACh was not affected in young rats but was improved in old rats. There was no difference in relaxation to the endothelium-independent dilator sodium nitroprusside between young, aged, and AdECSOD-treated old rats. Superoxide levels (lucigenin-enhanced chemiluminescence) were significantly increased in aged rats compared with young rats. After gene transfer of ECSOD to aged rats, superoxide levels in aorta were similar in old and young rats. Gene transfer of an ECSOD with the heparin-binding domain deleted had no effect on vascular function or superoxide levels in old rats. These results suggest that 1) vascular dysfunction associated with aging is mediated in part by increased levels of superoxide, 2) gene transfer of ECSOD reduces vascular superoxide and dysfunction in old rats, and <em>3</em>) beneficial effects of ECSOD in old rats require the heparin-binding domain of ECSOD.

Bovine Cu Zn <em>SOD</em> was used during an 8 year period as an antiinflammatory drug in 26 patients with severe Crohn's disease (CDAI <em>3</em>00) usually after failure of corticotherapy or when this drug was discontinued because of side effects or infection. This was a phase II trial during which doses routes of administration and concomitant therapies were progressively modified. We obtained 7<em>3</em>% good short term responses (judged upon CDAI and anatomic healing) and 82% positive results on long term evolution (the criteria were: i CDAI lower than 100 in between relapses, ii complete healing or notable improvement of lesions, iii no surgery needed, iv return to work. The acceptability was excellent with the free enzyme. Since the above described experience, published in Free Radical Biology and Medicine (1989, 7: 145-151), we used always the same treatment schedule (<em>SOD</em> 8 mg/day associated with Desferroxamine--500 mg subcutaneous every 2 days). The follow-up during the 87-89 period showed that 12 are in good health without any relapse, 9 experienced one or more relapses, and showed good responses upon resumption of treatment, 5 failed to respond to treatment, all part of the initial group on which <em>SOD</em> treatment had already failed, and among whom <em>3</em> were lost for follow-up before 1987, and two others took up another <em>SOD</em> treatment which also failed. <em>3</em> new patients (2 females, 1 male) were treated since then, and all <em>3</em> had positive results (one with disappearance of ileocoecal mass). The efficacy of <em>SOD</em> as an antiinflammatory drug in Crohn's disease needs to be confirmed by controlled trials.

Differential scanning calorimetry was used to measure changes in thermodynamic stability and aggregation for glycine 9<em>3</em> mutants of human copper, zinc-superoxide dismutase (<em>SOD</em>). Glycine 9<em>3</em> is a conserved residue at position i + <em>3</em> of a tight turn and has been found to be a mutational hot spot in familial amyotrophic lateral sclerosis (fALS). The fALS-associated mutations, G9<em>3</em>A, G9<em>3</em>S, G9<em>3</em>R, G9<em>3</em>D, and G9<em>3</em>V, were made in a pseudo wild-type background containing no free cysteines, which prevented the formation of aberrant disulfide bonds upon thermal unfolding, and enabled quantitative thermodynamic analysis of the effects of the mutations. Thermal unfolding was highly reversible for all the <em>SODs</em> in both the fully metallated (holo) and metal-free (apo) forms. The data for all the holo-<em>SODs</em> and for the apo-pseudo-wild-type <em>SOD</em> were well fit by a 2-state unfolding model for native dimer (N2) to two unfolded monomers (2U), N2 <->> 2U. The holo- and apo-forms of the mutants are significantly destabilized (by 1.5-<em>3</em>.5 kcal mol(-1) monomer) relative to the corresponding forms of pseudo wild-type, with the relative stabilities being correlated with statistical preferences for amino acids in this structural context. Although van't Hoff (DeltaHvH) to calorimetric (DeltaHcal) enthalpy ratios are close to unity for all the holo-<em>SODs</em> and for apo-pseudo-wild-type, consistent with a 2-state transition, DeltaHvH is considerably larger than DeltaHcal for all the apo-mutants. This suggests that the mutations cause apo-<em>SOD</em> to have an increased propensity to misfold or aggregate, which may be linked to increased toxic mutant <em>SOD</em> aggregation in fALS.

Ischemia/reperfusion (I/R) is an important problem in liver resection and transplantation that is associated with hepatocellular dysfunction and injury. This study was designed to investigate whether a difference in hepatocyte susceptibility occurs in the periportal (PP) and/or perivenous (PV) zones in response to hypoxia/reoxygenation (H/R), and to delineate the mechanisms underlying this susceptibility. H/R was induced in an in situ perfused mouse liver model with deoxygenated Krebs-Henseleit buffer followed by oxygenated buffer. Selective destruction of PP or PV sites was achieved by digitonin perfusion into the portal or inferior vena cava, and was confirmed by histological evaluations and zone-specific enzymes. Hepatocellular injury was assessed by alanine aminotransferase (ALT) release. In whole liver, H/R significantly increased perfusate ALT. H/R of PP-enriched zones caused ALT release that was similar to that of whole liver (80 + 10 vs. 70 + 12 U/mg protein), consistent with significant PP hepatocyte injury. Minimal ALT release occurred in PV zones (10 + 5 U/mg protein). Administration of N-acetyl L-cysteine or a chimeric superoxide dismutase (SOD)-SOD, a genetically engineered SOD-abrogated ALT release in H/R-perfused PP zones, implicating a role for superoxide (O(2) (-)). This elevated ALT release was attenuated by gadolinium chloride pretreatment, indicating that Kupffer cells are the O(2) (-) source. Enzymatic inhibition of cellular nitric oxide synthase (NOS) or genetic depletion of endothelial nitric oxide synthase (eNOS) aggravated hypoxia injury while exogenous NO and inducible nitric oxide synthase (iNOS) deficiency abolished reoxygenation injury. In conclusion, PP hepatocytes are more vulnerable to H/R; this injury is mediated directly or indirectly by Kupffer cell derived O(2) (-) and is limited by eNOS-derived NO.

Our previous research demonstrated that hepatic-protectant silibinin induced autophagy in human fibro-sarcoma HT1080 cells through reactive oxygen species (ROS) pathway. Pifithrin-α (PFT-α), a specific inhibitor of p5<em>3</em>, reduced autophagy and reversed silibinin's growth-inhibitory effect; besides, PFT-α decreased the activation of caspase-<em>3</em>, a crucial executor of apoptosis. Silibinin upregulated expression of p5<em>3</em>/phosphorylated-p5<em>3</em> (p-p5<em>3</em>) in a time-dependent manner. Catalase (scavenger of H(2)O(2)), superoxide dismutase (<em>SOD</em>) (scavenger of O(2)(•-)), and SB20<em>3</em>580 (inhibitor of p<em>3</em>8) attenuated upregulation of p5<em>3</em> expression, suggesting that p5<em>3</em> might be partially regulated by ROS-p<em>3</em>8 pathway. On the other hand, c-Jun N-terminal kinase (JNK) increased autophagic death in silibinin-treated cells, and JNK/p-JNK expression was upregulated by silibinin time-dependently. Inhibition of JNK by SP600125 did not influence generation of ROS. Scavengers of H(2)O(2) or O(2)(•-) showed no effect on expression of JNK/p-JNK, indicating that JNK might not correlate with ROS in this process. However, activation of p5<em>3</em> was suppressed by SP600125; therefore the function of p5<em>3</em> was possibly controlled by JNK as well. Western blotting analysis showed that PFT-α reduced activation of extracellular regulated kinase1/2 (ERK1/2) and expression of protein kinase B (PKB, or Akt)/p-Akt. PD98059 (inhibitor of mitogen-activated protein kinase kinase (MEK)/ERK) and wortmannin (inhibitor of phosphoinositide <em>3</em>-kinase (PI<em>3</em>K)/Akt) enhanced silibinin's cytotoxicity. Wortmannin augmented silibinin-induced autophagy, while PD98059 did not affect autophagic ratio. These results suggest that silibinin might induce p5<em>3</em>-mediated autophagic cell death by activating ROS-p<em>3</em>8 and JNK pathways, as well as inhibiting MEK/ERK and PI<em>3</em>K/Akt pathways.

Nephrotoxicity is one of the serious dose limiting side effects of cisplatin when used in the treatment of various malignant conditions. Accumulating evidence suggests that oxidative stress caused by free radicals and apoptosis of renal cells contributes to the pathogenesis of cisplatin-induced nephrotoxicity. Present study was aimed to explore the effect of carnosic acid, a potent antioxidant, against cisplatin induced oxidative stress and nephrotoxicity in rats. A single dose of cisplatin (7.5mg/kg) caused marked renal damage, characterized by a significant (P<0.05) increase in serum creatinine, blood urea nitrogen (BUN) and relative weight of kidney with higher kidney MDA (malondialdehyde), tROS (total reactive oxygen species), caspase <em>3</em>, GSH (reduced glutathione) levels and lowered tissue nitrite, <em>SOD</em> (superoxide dismutase), CAT (catalase), GSH-Px (glutathione peroxidase), GR (glutathione reductase) and GST (glutathione S-transferase) levels compared to normal control. Carnosic acid treatment significantly (P<0.05) attenuated the increase in lipid peroxidation, caspase-<em>3</em> and ROS generation and enhanced the levels of reduced glutathione, tissue nitrite level and activities of <em>SOD</em>, CAT, GSH-Px, GR and GST compared to cisplatin control. The present study demonstrates that carnosic acid has a protective effect on cisplatin induced experimental nephrotoxicity and is attributed to its potent antioxidant and antiapoptotic properties.

Curcumin is a natural antioxidant isolated from the medicinal plant Curcuma longa Linn. We previously reported that manganese complexes of curcumin (Cp-Mn) and diacetylcurcumin (DiAc-Cp-Mn) exhibited potent superoxide dismutase (<em>SOD</em>)-like activity in an in vitro assay. Nitric oxide (NO) is a free radial playing a multifaceted role in the brain and its excessive production is known to induce neurotoxicity. Here, we examined the in vivo effect of Cp-Mn and DiAc-Cp-Mn on NO levels enhanced by kainic acid (KA) and L-arginine (L-Arg) in the hippocampi of awake rats using a microdialysis technique. Injection of KA (10 mg/kg, i.p.) and L-Arg (1000 mg/kg, i.p.) significantly increased the concentration of NO and Cp-Mn and DiAc-Cp-Mn (50 mg/kg, i.p.) significantly reversed the effects of KA and L-Arg without affecting the basal NO concentration. Following KA-induced seizures, severe neuronal cell damage was observed in the CA1 and CA<em>3</em> subfields of hippocampal <em>3</em> days after KA administration. Pretreatment with Cp-Mn and DiAc-Cp-Mn (50 mg/kg, i.p.) significantly attenuated KA-induced neuronal cell death in both CA1 and CA<em>3</em> regions of rat hippocampus compared with vehicle control, and Cp-Mn and DiAc-Cp-Mn showed more potent neuroprotective effect than their parent compounds, curcumin and diacetylcurcumin. These results suggest that Cp-Mn and DiAc-Cp-Mn protect against KA-induced neuronal cell death by suppression of KA-induced increase in NO levels probably by their NO scavenging activity and antioxidative activity. Cp-Mn and DiAc-Cp-Mn have an advantage to be neuroprotective agents in the treatment of acute brain pathologies associated with NO-induced neurotoxicity and oxidative stress-induced neuronal damage such as epilepsy, stroke and traumatic brain injury.

Diabetes mellitus (DM) and hyperglycaemia are associated with platelet activation. The present study was designed to investigate how high glucose levels influence platelet function. Fasting human blood was incubated with different concentrations of D-glucose (5, 15 and <em>3</em>0 mmol/l) and other sugars without or with in vitro stimuli. Platelet activation was monitored by whole blood flow cytometry. High glucose levels enhanced adenosine diphosphate (ADP)- and thrombin receptor-activating peptide (TRAP)-induced platelet P-selectin expression, and TRAP-induced platelet fibrinogen binding. Similar effects were seen with <em>3</em>0 mmol/l L-glucose, sucrose and galactose. Hyperglycaemia also increased TRAP-induced platelet-leucocyte aggregation. Protein kinase C (PKC) blockade did not counteract the enhancement of platelet P-selectin expression, but abolished the enhancement of TRAP-induced platelet fibrinogen binding by hyperglycaemia. Superoxide anion scavenging by superoxide dismutase (<em>SOD</em>) attenuated the hyperglycaemic enhancement of platelet P-selectin expression, but did not counteract the enhancement of TRAP-induced platelet fibrinogen binding. Hyperglycaemia did not alter platelet intracellular calcium responses to agonist stimulation. Blockade of cyclo-oxygenase (COX), phosphotidylinositol-<em>3</em> (PI<em>3</em>) kinase, or nitric oxide synthase, or the addition of insulin did not influence the effect of hyperglycaemia. In conclusion, high glucose levels enhanced platelet reactivity to agonist stimulation through elevated osmolality. This occurred via superoxide anion production, which enhanced platelet P-selectin expression (secretion), and PKC signalling, which enhanced TRAP-induced fibrinogen binding (aggregablity).

OBJECTIVE

SSc is characterized by the overproduction of extracellular matrix (ECM) proteins, such as collagen and fibronectin, by activated fibroblasts, as well as oxidative stress. This study investigates the anti-fibrotic potential of the antioxidant epigallocatechin-<em>3</em>-gallate (EGCG) on activated dermal fibroblasts from SSc patients.

METHODS

Dermal fibroblasts from a cell line (AG), healthy individuals (CON) and SSc patients were treated with EGCG, TGF-β, PDGF-BB or other antioxidants [antioxidants superoxide dismutase (SOD), catalase, N-acetyl-L-cysteine (NAC) and diphenyleneiodonium (DPI)]. Collagen type I, fibronectin, connective tissue growth factor (CTGF), α-smooth muscle actin and mitogen-activated protein (MAP) kinases were measured by ELISA and western blot. Fibroblast contractile forces were measured by collagen gel contraction. Reactive oxygen species (ROS) were assessed by dichlorofluorescein assay and nuclear factor κ beta (NF-κB) activity by DNA binding assay.

RESULTS

EGCG (1-100 µM) dose-dependently decreased collagen type I secretion in culture medium after 24 h in AG fibroblasts. Collagen type I protein expression in cell lysates was also significantly reduced by 40% in EGCG-treated cells (40 µM). Furthermore, EGCG also down-regulated TGF-β-induced collagen type I, fibronectin and CTGF. Similarly, in CON fibroblasts EGCG decreased basal and stimulated collagen type I, fibronectin and CTGF after 24 h, while in SSc the effects of the antioxidant were apparent after 48 h. Fibroblast-mediated contraction of collagen gels was inhibited by EGCG as early as 1 h in AG fibroblasts, and in the CON and SSc fibroblasts. Additionally, EGCG also inhibited TGF-β-stimulated gel contraction similar to other antioxidants DPI and NAC, but not SOD or catalase. EGCG suppressed TGF-β-induced ROS production in all fibroblasts. Furthermore, EGCG inhibited TGF-β or PDGF-BB-induced phospho-extracellular signal-regulated kinase (ERK)1/2 MAP kinase and NF-κB activity in SSc fibroblasts.

CONCLUSIONS

The results suggest that the antioxidant, EGCG, can reduce ECM production, the fibrotic marker CTGF and inhibit contraction of dermal fibroblasts from SSc patients. Furthermore, EGCG was able to suppress intracellular ROS, ERK1/2 kinase signalling and NF-κB activity. Taken together, EGCG may be a possible candidate for therapeutic treatment aimed at reducing both oxidant stress and the fibrotic effects associated with SSc.

Different signaling pathways are involved in tissue protection against ischemia reperfusion (IR) injury, among them mammalian target of rapamycin (mTOR) and related pathways have been examined in many recent studies. Present study evaluated the role of mTOR in remote ischemic preconditioning (RIPC) of hippocampus. Renal ischemia was induced (<em>3</em> cycles of 5min occlusion and 5min reperfusion of unilateral renal artery) 24h before global brain ischemia (20min bilateral common carotid artery occlusion). Saline or rapamycin (mTOR inhibitor; 5mg/kg, i.p.) was injected <em>3</em>0min before RIPC. mTOR and phosphorylated mTOR (p-mTOR) expression, superoxide dismutase (<em>SOD</em>) activity and retention trial of passive avoidance test were determined 24h after global ischemia. Apoptosis and neuronal cell density were assessed 72h after hippocampal ischemia. RIPC decreased apoptosis (p<0.05 vs. IR), improved memory (p<0.05 vs. IR), and augmented p-mTOR expression and <em>SOD</em> activity after hippocampal ischemia (p<0.05 vs. IR). Rapamycin abolished all protective effects of RIPC (p<0.05 vs. RIPC+IR) suggesting a role for mTOR in RIPC induced hippocampal protection.

We evaluated the hypothesis that postischemic renal failure is caused primarily at reperfusion by oxygen-derived free radicals in a swine model designed to realistically mimick human cadaveric renal transplantation. Both kidneys were removed, flushed with Euro-Collins solution, stored 24 hr at 4 degrees C, and then transplanted to a second pig. Experiments were paired, each pig receiving one treated and one control kidney. All pigs received the optimal conventional regimen of hydration, phenoxybenzamine, furosemide, and mannitol to allow assessment of free radical treatment superimposed thereupon. Two days later creatinine clearance (CCR) was measured from each kidney via separate ureterostomies. Untreated kidneys developed severe functional impairment, CCR falling from a normal level of 25.5 +/- 6.<em>3</em> ml/min (n = 8) to 7.7 +/- 0.9 ml/min (n = 14, P less than .05 vs. control). The infusion of 20 mg of the free radical scavenger superoxide dismutase (<em>SOD</em>) into the renal artery at reperfusion substantially ameliorated this injury (CCR = 15.9 +/- 1.7 ml/min, n = 18, P less than 0.05 vs. control). A dose-response curve to <em>SOD</em> showed no effect of doses of 0.2 mg (CCR = 8.0 +/- 1.1 ml/min, n = 4) or 2 mg (CCR = 7.7 +/- 0.9, n = 5), and no greater benefit from 100 mg (CCR = 16.1 +/- 2.1 ml/min, n = <em>3</em>, P less than 0.05 vs. control). Blocking the generation of superoxide radicals from xanthine oxidase with allopurinol (50 mg/kg) afforded similar protection (CCR = 18.2 +/- 1.8; n = 11, P less than 0.01 vs. control). On the other hand, following an 18-hr period of cold ischemia, little damage was sustained by the untreated (control) kidneys (CCR = 22.1 +/- 0.6 ml/min). Consequently, under these conditions the ablation of free radical generation with allopurinol provided no significant benefit. These findings suggest that after a critical period of cold ischemic preservation, metabolic changes take place within the kidney that lead to free radical generation and consequent tissue injury upon reperfusion, despite optimal preservation by conventional methods. This damage can be prevented by simple nontoxic measures--which, therefore, show great promise for use in the prevention of early renal failure following cadaveric renal transplantation.

The protective role of exogenously supplied selenium (Se) and polyamines (PAs) such as putrescine (Put) and spermine (Spm) in detoxifying the cadmium (Cd) induced toxicity was studied in the marine red alga Gracilaria dura in laboratory conditions. The Cd exposure (0.4 mM) impede the growth of alga while triggering the reactive oxygen species (ROS viz. O(2)(•-) and H(2)O(2)) generation, inhibition of antioxidant system, and enhancing the lipoxygenase (LOX) activity, malondialdehyde (MDA) level and demethylation of DNA. Additions of Se (50 μM) and/or Spm (1 mM) to the culture medium in contrast to Put, efficiently ameliorated the Cd toxicity by decreasing the accumulation of ROS and MDA contents, while restoring or enhancing the level of enzymatic and nonenzymatic antioxidants and their redox ratio, phycobiliproteins and phytochelatins, over the controls. The isoforms of antioxidant enzymes namely superoxide dismutase (Mn-<em>SOD</em>, ~150 kDa; Fe-<em>SOD</em> ~120 kDa), glutathione peroxidase (GSH-Px, ~120 and 140 kDa), glutathione reductase (GR, ~110 kDa) regulated differentially to Se and/or Spm supplementation. Furthermore, it has also resulted in enhanced levels of endogenous PAs (specially free and bound insoluble Put and Spm) and n-6 PUFAs (C20-<em>3</em>, n-6 and C20-4, n-6). This is for the first time wherein Se and Spm were found to regulate the stabilization of DNA methylation by reducing the events of cytosine demethylation in a mechanism to alleviate the Cd stress in marine alga. The present findings reveal that both Se and Spm play a crucial role in controlling the Cd induced oxidative stress in G. dura.

The poor prognosis of glioblastoma multiforme and lack of effective therapy have necessitated the identification of new treatment strategies. We have previously reported that elevation of oxidative stress induces apoptosis of glioma cells. Because the farnesyltransferase inhibitor manumycin is known to induce reactive oxygen species (ROS) generation, we evaluated the effects of manumycin on glioma cells. Manumycin induced glioma cell apoptosis by elevating ROS generation. Treatment with the ROS inhibitor N-acetylcysteine blocked manumycin-induced apoptosis, caspase-<em>3</em> activity, and PARP expression, indicating the involvement of increased ROS in the proapoptotic activity of manumycin. This heightened ROS level was accompanied by a concurrent decrease in antioxidants such as superoxide dismutase (<em>SOD</em>-1) and thioredoxin (TRX-1). <em>SOD</em>-1 overexpression protects glioma cells from manumycin-induced apoptosis. In addition, small interfering RNA-mediated knockdown of <em>SOD</em>-1 and TRX-1 expression also increased ROS generation and sensitivity of glioma cells to manumycin-induced cell death. Interestingly, suppressing ROS generation prevented manumycin-induced Ras inhibition. This study reports for the first time that Ras inhibition by manumycin is due to heightened ROS levels. We also report for the first time that manumycin inhibits the phosphorylation of signal transducer and activator of transcription <em>3</em> and telomerase activity in a ROS-dependent manner, which plays a crucial role in glioma resistance to apoptosis. In addition manumycin (i) induced the DNA-damage repair response, (ii) affected cell-cycle-regulatory molecules, and (iii) impaired the colony-forming ability of glioma cells in a ROS-dependent manner.

OBJECTIVE

To investigate the effects of reactive oxygen species (ROS) on the micturition reflex in vivo, especially in bladder afferent signalling in rats, as several pathophysiological conditions in the urinary bladder (e.g. ischaemia/reperfusion and inflammation) are characterized by the formation of ROS.

METHODS

Adult female Sprague-Dawley rats under urethane anaesthesia (normal or pretreated with 125 mg/kg capsaicin, subcutaneously, 4 days before) were assessed by continuous cystometrography (CMG) with or without the intravesical administration of H(2)O(2) (0.00<em>3</em>-<em>3</em>%) to stimulate ROS damage. To investigate the mechanism of H(2)O(2), catalase (a H(2)O(2) scavenger) was applied intravesically (2000 IU/mL), or rats were given intravenous injections with superoxide dismutase (<em>SOD</em>, 20,000 IU/kg, a superoxide anion scavenger), dimethylthiourea (DMTU, 100 mg/kg, a hydroxyl radical scavenger), deferoxamine (20 mg/kg, an iron-chelator that prevents the formation of hydroxyl radical), indomethacin (<em>3</em> mg/kg, a cyclooxygenase inhibitor) or ketoprofen (1 mg/kg, a cyclooxygenase inhibitor) just before or during the intravesical administration of H(2)O(2). Prostaglandin (PG) levels (PGE(2) and 6-keto-PGF(1 alpha)) were measured in the bladder of rats treated with intravesical 0.<em>3</em>% H(2)O(2) for <em>3</em>0 min with or without indomethacin.

RESULTS

Intravesical administration of H(2)O(2) induced detrusor overactivity, as shown by a reduction in the mean (sem) intercontraction interval (ICI), in a dose-dependent manner in normal rats (0.<em>3</em>% H(2)O(2,) P < 0.01, <em>3</em>6.2 (4.7)% of the control ICI). H(2)O(2)-induced detrusor overactivity was almost abolished by catalase and significantly suppressed by DMTU, deferoxamine, capsaicin pretreatment, indomethacin or ketoprofen but not by <em>SOD</em>. The level of PGs was significantly increased by H(2)O(2) instillation, and indomethacin significantly inhibited the increase in PGs.

CONCLUSIONS

These results indicate that oxidative stress induced by H(2)O(2) activates capsaicin-sensitive C-fibre afferent pathways, at least in part, mediated via stimulation of the cyclooxygenase pathway, thereby inducing detrusor overactivity. Thus, rats treated with intravesical H(2)O(2) appear to be a suitable model for the study of detrusor overactivity.

Antioxidant-rich fractions were extracted from grape (Vitis vinifera) pomace using ethyl acetate, methanol, and water. The extracts were screened for their potential as antioxidants in different models. The ethyl acetate, methanol, and water extracts showed 76, 87.1, and 21.7% antioxidant activities at 100 ppm, respectively, using the 1,1-diphenyl-2-picrylhydrazyl model system. As the methanol extract of grape pomace showed maximum antioxidant activity among all of the extracts, it was selected to determine its effect on lipid peroxidation, hydroxyl radical scavenging activity, and human low-density lipoprotein (LDL) oxidation. The methanol extract showed 71.7, 7<em>3</em>.6, and 91.2% inhibition using the thiobarbituric acid method, hydroxyl radical scavenging activity, and LDL oxidation, respectively, at 200 ppm. Treatment of albino rats of the Wistar strain with a single dose of CCl(4) at 1.25 mL/kg of body weight decreases the activities of catalase, superoxide dismutase (<em>SOD</em>), and peroxidase by 81, 49, and 89%, respectively, whereas the lipid peroxidation value increased nearly <em>3</em>-fold. Pretreatment of the rats with the methanolic extract of grape pomace at 50 mg/kg (in terms of catechin equivalents) followed by CCl(4) treatment causes restoration of catalase, <em>SOD</em>, and peroxidase by 4<em>3</em>.6, 7<em>3</em>.2, and 54%, respectively, as compared with control, whereas lipid peroxidation was restored to values comparable with the control. Histopathological studies of the liver of different groups also support the protective effects exhibited by the methanol extract of grape pomace by restoring the normal hepatic architecture. Owing to this property, the studies on grape pomace can be further extended to exploit its possible application for the preservation of food products as well as a health supplement and neutraceutical.

Ras p21 signaling is involved in multiple aspects of growth, differentiation, and stress response [1-2]. There is evidence pointing to superoxides as relays of Ras signaling messages. Chemicals with antioxidant activity suppress Ras-induced DNA synthesis. The inhibition of Ras significantly reduces the production of superoxides by the NADPH-oxidase complex [<em>3</em>]. Kirsten and Harvey are nonallelic Ras cellular genes that share a high degree of structural and functional homology. The sequences of Ki- and Ha-Ras proteins are almost identical. They diverge only in the 20-amino acid hypervariable domain at the COOH termini. To date, their functions remain indistinguishable [4]. We show that Ki- and Ha-Ras genes differently regulate the redox state of the cell. Ha-Ras-expressing cells produce high levels of reactive oxygen species (ROS) by inducing the NADPH-oxidase system. Ki-Ras, on the other hand, stimulates the scavenging of ROS by activating posttranscriptionally the mitochondrial antioxidant enzyme, Mn-superoxide dismutase (Mn-<em>SOD</em>), via an ERK1/2-dependent pathway. Glutamic acid substitution of the four lysine residues in the polybasic stretch at the COOH terminus of Ki-Ras completely abolishes the activation of Mn-<em>SOD</em>, although it does not inhibit ERK1/2-induced transcription. In contrast, an alanine substitution of the cysteine of the CAAX box has very little effect on Mn-<em>SOD</em> activity but eliminates ERK1/2- dependent transcription.

Extracts from various morphological parts of Annona muricata Linn. (Annonaceae) are widely used medicinally in many parts of the world for the management, control and/or treatment of a plethora of human ailments, including diabetes mellitus (DM). The present study was undertaken to investigate the possible protective effects of A. muricata leaf aqueous extract (AME) in rat experimental paradigms of DM. The animals used were broadly divided into four (A, B, C and D) experimental groups. Group A rats served as 'control' animals and received distilled water in quantities equivalent to the administered volumes of AME and reference drugs' solutions intraperitoneally. Diabetes mellitus was induced in Groups B and C rats by intraperitoneal injections of streptozotocin (STZ, 70 mg kg(-1)). Group C rats were additionally treated with AME (100 mg kg(-1) day(-1), p.o.) as from day <em>3</em> post STZ injection, for four consecutive weeks. Group D rats received AME (100 mg kg(-1) day(-1) p.o.) only for four weeks. Post-euthanization, hepatic tissues were excised and processed biochemically for antioxidant enzymes and lipid profiles, such as catalase (CAT), reactive oxygen species (ROS), glutathione (GSH), superoxide dismutase (<em>SOD</em>), glutathione peroxidase (GSH-Px), thiobarbituric acid reactive substances (TBARS), triglycerides (TG), total cholesterol (TC), high density lipoprotein (HDL) and low density lipoprotein (LDL), respectively. Treatment of Groups B and C rats with STZ (70 mg kg(-1) i. p.) resulted in hyperglycaemia, hypoinsulinaemia, and increased TBARS, ROS, TC, TG and LDL levels. STZ treatment also significantly decreased (p<0.05) CAT, GSH, <em>SOD</em>, GSH-Px activities, and HDL levels. AME-treated Groups C and D rats showed significant decrease (p<0.05) in elevated blood glucose, ROS, TBARS, TC, TG and LDL. Furthermore, AME treatment significantly increased (p<0.05) antioxidant enzymes' activities, as well as serum insulin levels. The findings of this laboratory animal study suggest that A. muricata extract has a protective, beneficial effect on hepatic tissues subjected to STZ-induced oxidative stress, possibly by decreasing lipid peroxidation and indirectly enhancing production of insulin and endogenous antioxidants.

Recent studies have demonstrated that miR-<em>3</em>4a expression is significantly upregulated and associated with apoptosis in nonalcoholic fatty liver disease (NAFLD). Carnosic acid (CA) is a novel antioxidant and a potential inhibitor of apoptosis in organ injury, including liver injury. This study aimed to investigate the signaling mechanisms underlying miR-<em>3</em>4a expression and the antiapoptotic effect of CA in NAFLD. CA treatment significantly reduced the high-fat diet (HFD)-induced elevations in aminotransferase activity as well as in serum triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and malondialdehyde (MDA) levels but increased serum high-density lipoprotein cholesterol (HDL-C) and hepatic superoxide dismutase (<em>SOD</em>) levels. Moreover, CA treatment ameliorated the increase in cleaved caspase-<em>3</em> caused by HFD exposure and completely reversed the HFD-induced decreases in manganese superoxide dismutase (Mn<em>SOD</em>) and B-cell lymphoma-extra large expression. CA also counteracted the HFD- or palmitic acid (PA)-induced increases in caspase-<em>3</em> and caspase-9 activity. Mechanistically, CA reversed the HFD- or PA-induced upregulation of miR-<em>3</em>4a, which is the best-characterized regulator of SIRT1. Importantly, the decrease in miR-<em>3</em>4a expression was closely associated with the activation of the SIRT1/p66shc pathway, which attenuates hepatocyte apoptosis in liver ischemia/reperfusion injury. A dual luciferase assay in L02 cells validated the modulation of SIRT1 by CA, which occurs at least partly via miR-<em>3</em>4a. In addition, miR-<em>3</em>4a overexpression was significantly counteracted by CA, which prevented the miR-<em>3</em>4a-dependent repression of the SIRT1/p66shc pathway and apoptosis. Collectively, our results support a link between liver cell apoptosis and the miR-<em>3</em>4a/SIRT1/p66shc pathway, which can be modulated by CA in NAFLD.

To determine if some specific "preparation for birth" occurs in the developing lung to help assure its successful adaptation to a comparatively O2-rich world at birth, we measured the activities of the antioxidant enzymes in the developing lungs of rabbit fetuses from 10 d before parturition to several days after birth. Superoxide dismutase (<em>SOD</em>), catalase (CAT), and glutathione peroxidase (GP) activities showed similar maturational patterns with significant increases in activity, compared with earlier gestational levels, during the last <em>3</em>-5 d before birth. During the final days in utero, <em>SOD</em> and CAT activities increased by approximately 110% and lung GP activity by approximately 200%. There were no parallel changes in lung O2 consumption demonstrable over this same prenatal period.

Natural products, an infinite treasure of bioactive chemical entities, persist as an inexhaustible resource for discovery of drugs. This review article intends to emphasize on one of the naturally occurring flavonoids, astragalin (kaempferol <em>3</em>-glucoside), which is a bioactive constituent of various traditional medicinal plants such as Cuscuta chinensis. This multifaceted compound is well known for its diversified pharmacological applications such as anti-inflammatory, antioxidant, neuroprotective, cardioprotective, antiobesity, antiosteoporotic, anticancer, antiulcer, and antidiabetic properties. It carries out the aforementioned activities by the regulation and modulation of various molecular targets such as transcription factors (NF-κB, TNF-α, and TGF-β1), enzymes (iNOS, COX-2, PGE2, MMP-1, MMP-<em>3</em>, MIP-1α, COX-2, PGE-2, HK2, AChe, <em>SOD</em>, DRP-1, DDH, PLCγ1, and GPX), kinases (JNK, MAPK, Akt, ERK, SAPK, IκBα, PI<em>3</em>K, and PKCβ2), cell adhesion proteins (E-cadherin, vimentin PAR-2, and NCam), apoptotic and antiapoptotic proteins (Beclin-1, Bcl-2, Bax, Bcl-xL, cytochrome c, LC<em>3</em>A/B, caspase-<em>3</em>, caspase-9, procaspase-<em>3</em>, procaspase-8, and IgE), and inflammatory cytokines (SOCS-<em>3</em>, SOCS-5, IL-1β, IL-4, IL-6, IL-8, IL-1<em>3</em>, MCP-1, CXCL-1, CXCL-2, and IFN-γ). Although researchers have reported multiple pharmacological applications of astragalin in various diseased conditions, further experimental investigations are still mandatory to fully understand its mechanism of action. It is contemplated that astragalin could be subjected to structural optimization to ameliorate its chemical accessibility, to optimize its absorption profiles, and to synthesize its more effective analogues which will ultimately lead towards potent drug candidates.

Ginkgo biloba extract (EGb), a potent antioxidant and monoamine oxidase B (MAO-B) inhibitor, was evaluated for its anti-parkinsonian effects in a 6-hydroxydopamine (6-OHDA) rat model of the disease. Rats were treated with 50, 100, and 150 mg/kg EGb for <em>3</em> weeks. On day 21, 2 microL 6-OHDA (10 microg in 0.1% ascorbic acid saline) was injected into the right striatum, while the sham-operated group received 2 microL of vehicle. Three weeks after 6-OHDA injection, rats were tested for rotational behaviour, locomotor activity, and muscular coordination. After 6 weeks, they were killed to estimate the generation of thiobarbituric acid reactive substances (TBARS) and reduced glutathione (GSH) content, to measure activities of glutathione-S-transferase (GST), glutathione reductase (GR), glutathione peroxidase (GPx), catalase, and superoxide dismutase (<em>SOD</em>), and to quantify catecholamines, dopamine (DA) D2 receptor binding, and tyrosine hydroxylase-immunoreactive (TH-IR) fibre density. The increase in drug-induced rotations and deficits in locomotor activity and muscular coordination due to 6-OHDA injections were significantly and dose-dependently restored by EGb. The lesion was followed by an increased generation of TBARS and significant depletion of GSH content in substantia nigra, which was gradually restored with EGb treatment. EGb also dose-dependently restored the activities of glutathione-dependent enzymes, catalase, and <em>SOD</em> in striatum, which had reduced significantly by lesioning. A significant decrease in the level of DA and its metabolites and an increase in the number of dopaminergic D2 receptors in striatum were observed after 6-OHDA injection, both of which were significantly recovered following EGb treatment. Finally, all of these results were exhibited by an increase in the density of TH-IR fibers in the ipsilateral substantia nigra of the lesioned group following treatment with EGb; the lesioning had induced almost a complete loss of TH-IR fibers. Considering our behavioural studies, biochemical analysis, and immunohistochemical observation, we conclude that EGb can be used as a therapeutic approach to check the neuronal loss following parkinsonism.

Sonchus asper (SA) is locally used in renal aliments. The present work investigated the antioxidant effects of S. asper methanolic extract (SAME) against CCl(4)-induced nephrotoxicity in Sprague-Dawley male rats. CCl(4) (<em>3</em> ml/kg b.w., i.p.; <em>3</em>0% in olive oil) biweekly for 4 weeks induced lipid peroxidation, as reflected by significant increase of TBARS; diminished the renal antioxidant defenses, as revealed by a decrease of the level of GSH, CAT, <em>SOD</em>, GST, GSR, GSH-Px and QR while elevated the level of gamma-GT, H(2)O(2) and nitrite contents. CCl(4) caused histopathological injuries and significantly increased the renal AgNORs count and DNA damage. Telomerase activity in kidney was determined positive with CCl(4) treatment. Creatinine, urobilinogen and urea concentration was increased whereas creatinine clearance was decreased in serum and urine. Level of protein and albumin was increased in urine while reduced in serum. Serum level of nitrite was increased with CCl(4) treatment. Treatment of rats with SAME (100, 200mg/kg b.w.) effectively ameliorated the alterations induced with CCl(4) in lipid peroxidation, antioxidant defenses, biochemical markers, genotoxicity and renal lesions. The present data suggests that SAME protect the kidneys possibly by alleviating the oxidative stress induced with CCl(4) in rat.

The use of DOX (doxorubicin), an antibiotic used in oncological treatments, is limited by a dose-related cardiotoxicity against which acute exercise is protective. However, the mitochondrial-related mechanisms of this protection remain unknown. Therefore the present study aimed to determine the effects of an acute endurance exercise bout performed 24 h before DOX treatment on heart and liver mitochondrial function. A total of 20 adult male Wistar rats were divided into groups as follows: non-exercised with saline (NE + SAL), non-exercised DOX-treated (NE + DOX), exercised with saline (EX + SAL) and exercised DOX-treated (EX + DOX). The animals performed a 60 min exercise bout on a treadmill or remained sedentary 24 h before receiving either a DOX bolus (20 mg/kg of body weight) or saline. Heart and liver mitochondrial function [oxygen consumption, membrane potential (DeltaPsi) and cyclosporin-A-sensitive calcium-induced MPTP (mitochondrial permeability transition pore) opening] were evaluated. The activities of the respiratory complex, Mn-<em>SOD</em> (superoxide dismutase), caspases <em>3</em> and 9, as well as the levels of ANT (adenine nucleotide translocase), VDAC (voltage-dependent anion channel), CypD (cyclophilin D), Bax and Bcl-2, were measured. Acute exercise prevented the decreased cardiac mitochondrial function (state <em>3</em>, phosphorylative lagphase; maximal DeltaPsi generated both with complex I- and II-linked substrates and calcium-induced MPTP opening) induced by DOX treatment. Exercise also prevented the DOX-induced decreased activity of cardiac mitochondrial chain complexes I and V, and increased caspase <em>3</em> and 9 activities. DOX administration and exercise caused increased cardiac mitochondrial <em>SOD</em> activity. Exercise ameliorated liver mitochondrial complex activities. No alterations were observed in the measured MPTP and apoptosis-related proteins in heart and liver mitochondria. The results demonstrate that acute exercise protects against cardiac mitochondrial dysfunction, preserving mitochondrial phosphorylation capacity and attenuating DOX-induced decreased tolerance to MPTP opening.