Objective: To observe and compare the cytological and biological differences between human normal and degenerated nucleus pulposus (NP), and to investigate the repair effect of insulin-like growth factor 1 (IFG-1) and platelet derived growth factor (PDGF) on human degenerated NP.
Methods: Human degenerative and normal NP tissues were obtained from operative patients, a portion of which were processed into tissue sections and HE staining was performed to observe the morphological changes of nucleus pulposus cells (NPCs) before and after degeneration of NP. Immunohistochemistry staining was used to determine the expression levels of collagen type Ⅰ, collagen type Ⅱ, B-cell lymphoma 2 (Bcl-2), Bcl-2 associated X (Bax) proteins. Another portion of tissues were isolated and cultured and NPCs morphology was observed under inverted microscope. Western blot analysis was used to detect collagen type Ⅱ protein expression. Then, the gene transfection experiments were launched, including 4 groups, with group A designed as degenerated NPCs only, and groups B, C, and D of degenerated NPCs transfected with IGF-1 gene lentiviral particles, PDGF gene lentiviral particles, and lentiviral particles carrying IGF-1 and PDGF double genes, respectively. At 21 days after transfection, the cell morphology of each group was observed under inverted microscope, the positive rates of IGF-1 and PDGF of each group were measured by flow cytometry, and the expression of collagen type Ⅱ protein was detected by using immunohistochemistry staining and Western blot.
Results: HE staining showed that there were a large number of notochordal cells and a small number of chondrocytes in the central NP tissue of normal group, while the NPCs in degeneration group were significantly reduced, and a large proportion of fibrocartilage tissues were found in NP tissue. Immunohistochemistry staining showed that the percentages of collagen type Ⅰ and Bax protein-positive cells in degeneration group were significantly higher than those of normal group, while the percentages of collagen type Ⅱ and Bcl-2 protein-positive cells were significantly lower than those of normal group ( P<0.05). Western blot showed that the relative expression level of collagen type Ⅱ protein in degeneration group was significantly lower than that in normal group ( t=65.493, P=0.000). At 21 days after gene transfection, compared with group A, the cell viability of groups B, C, and D increased and the morphology became more regular. Flow cytometry showed that the percentages of IGF-1-positive cells in groups B and D were significantly higher than that in group A, and the percentages of PDGF-positive cells in groups C and D were significantly higher than that in group A ( P<0.05). Immunohistochemistry staining showed that the positive stainings of collagen type Ⅱ in groups A, B, C, and D was (±), (+), (+), and (++), respectively. Western blot showed that the relative expression of collagen type Ⅱ protein in groups A, B, C, and D increased by degrees, and the differences between groups were significant ( P<0.05).
Conclusion: Both IGF-1 and PDGF can reverse the degeneration of intervertebral discs NPCs and they have synergistic effects, providing experimental basis for its application in clinical treatment approaches for degenerative disc disease.
目的: 观察比较人正常和退变髓核的细胞学和生物学差异,并研究 IFG-1 和 PDGF 对人退变髓核的修复作用。.
方法: 取患者自愿捐赠的人退变及正常髓核组织,一部分制作成组织切片,进行 HE 染色观察髓核退变前后形态变化,免疫组织化学染色观察Ⅰ型胶原、Ⅱ型胶原、B 淋巴细胞瘤 2(B-cell lymphoma 2,Bcl-2)、Bcl-2 相关 X(Bcl-2 associate X,Bax)蛋白表达;另一部分髓核组织进行细胞培养,倒置显微镜观察细胞形态,Western blot 检测Ⅱ型胶原蛋白表达。然后进行基因转染实验,分为 4 组,A 组为退变髓核细胞;B、C、D 组分别用 IGF-1 基因慢病毒颗粒、PDGF 基因慢病毒颗粒和携带 IGF-1、PDGF 双基因的慢病毒颗粒转染退变髓核细胞。转染 21 d,倒置显微镜观察各组细胞形态,流式细胞仪测定各组细胞 IGF-1 和 PDGF 阳性率,免疫组织化学染色和 Western blot 检测各组细胞Ⅱ型胶原蛋白表达。.
结果: HE 染色示,正常组中央髓核组织可见大量脊索细胞和少量类软骨细胞;而退变组髓核细胞明显减少,且髓核组织内可见大量纤维软骨组织。免疫组织化学染色示,退变组Ⅰ型胶原、Bax 蛋白阳性细胞百分比显著高于正常组,Ⅱ型胶原、Bcl-2 蛋白阳性细胞百分比显著低于正常组,差异均有统计学意义( P<0.05)。Western blot 检测示,退变组Ⅱ型胶原蛋白相对表达量显著低于正常组( t=65.493, P=0.000)。基因转染后 21 d,与 A 组比较,B、C、D 组细胞活性增加,形态变得较为规则。流式细胞仪检测示 B、D 组 IGF-1 阳性率较 A 组明显增高,C、D 组PDGF 阳性率较 A 组明显增高( P<0.05)。免疫组织化学染色观察示,A、B、C、D 组Ⅱ型胶原蛋白阳性染色情况依次为(±)、(+)、(+)、(++)。Western blot 检测示,A、B、C、D 组Ⅱ型胶原蛋白相对表达量依次增加,各组间比较差异均有统计学意义( P<0.05)。.
结论: IGF-1 与 PDGF 均能逆转椎间盘髓核细胞的退变且二者具有协同作用,为其今后应用于临床治疗椎间盘退变性疾病提供了实验依据。.
Keywords: Intervertebral disc degeneration; gene transfection; insulin-like growth factor 1; nucleus pulposus; platelet derived growth factor.