OBJECTIVE

To investigate the structural changes in the cytoskeleton (microtubules, microfilaments) and examine the expression of centrosomal functional proteins during human spermiogenesis.

METHODS

Immunofluorescent staining of human spermiogenic cells.

METHODS

University hospital and IVF clinic.

METHODS

Human testicular tissues were obtained by testicular sperm aspiration (TESA) under informed consent. Three cases of obstructive azoospermia, with confirmed normal spermatogenesis, were examined.

METHODS

Spermatogenic cells were fixed with microtubule-stabilizing buffer. Immunocytochemical detection of microtubules, microfilaments, and centrosome was performed using monoclonal antibodies against alpha- and beta-tubulin, phalloidin, and functional centrosomal proteins.

METHODS

Samples were examined using epifluorescence and laser scanning confocal microscopes.

RESULTS

During the Sb2 period, microtubules formed the manchette structure, which extended from the equator of the nucleus through the cytoplasm. Microfilaments were organized in the periacrosamal region during spermiogenesis (Sa to Sd). Although centrin was observed throughout the spermiogenic period, gamma-tubulin was detected only in the Sb2 period.

CONCLUSIONS

Dynamic cytoskeletal movement was observed during human spermiogenesis. Cytoskeletal rearrangements in the Sb2 period appear to play important roles in the morphologic changes that occur during human spermiogenesis. Studies of the cytoskeletal system during spermiogenesis may help identify some causes of male infertility (e.g., teratozoospermia, maturation arrest).