Altered distribution of Sertoli cell vimentin and increased apoptosis in cryptorchid rats

Sertoli cell cytoskeletons play an important role in the process of spermatogenesis. The authors investigated the effects of cryptorchidism in immature rats on the distribution of Sertoli cell cytoskeletons and the incidence of testis germ cell apoptosis.

Immature 3-week-old rats were made cryptorchid unilaterally, and the distribution of Sertoli cell cytoskeletons by immunohistochemistry and germ cell apoptosis by TUNEL technique were evaluated at different day intervals.

Immunohistochemical staining from control rats showed that the distribution of vimentin in Sertoli cells changes in developing rats. Basally, it is localized in the perinuclear region of the cell as well as in filament networks that project into the apical Sertoli cell cytoplasm in a "spokelike" pattern. In cryptorchidism, there was an intense vimentin immunoreactivity surrounding Sertoli cell nuclei along with the collapse of the apical extensions. This became significantly evident by 7 days. Microtubules occur in Sertoli cell cytoplasm apical to the nucleus. Cryptorchidism did not alter their distribution. Spontaneous apoptosis of germ cells occurs in the control testis, and a markedly increased incidence of apoptosis was observed in cryptorchidism by 7 days with decreased testis weight.

Taken together, the authors propose that Sertoli cells are affected in cryptorchidism, and altered distribution of Sertoli cells vimentin filaments correlates with the increased germ cell apoptosis. Sertoli cell vimentin filaments are important for maintaining the structural integrity of the seminiferous epithelium.