Expression of Fas-Fas ligand in murine testis

PROBLEM: During spermatogenesis, it has been suggested that the number of g erm cells to be matured is regulated and restricted through the apoptotic m echanism. In the present study, we investigated the expression and apoptoti c role of Fas and Fas ligand (L) in the murine testis. METHOD OF STUDY: The expression of Fas-FasL in the murine testis was assess ed by reverse transcriptase-polymerase chain reaction (RT-PCR)-Southern blo t hybridization, in situ hybridization, and Western blot methods. The termi nal deoxynucleotide transferase mediated dUTP-nick end label (TUNEL) and DN A fragmentation methods were applied to detect the generation of apoptosis in germ cells. RESULTS: By means of RT-PCR-Southern blot hybridization, we demonstrated th e positive expression of Fas in testicular germ cells, and of Fast in testi cular cells, supporting the findings with in situ hybridization that Fas wa s localized in germ cells, whereas Fast was localized in Sertoli cells of m urine testis. A specific band at 45 kDa was obtained in the lysates from te stis and germ cells with Western blot analysis. Then, the co-incubation of germ cells with Spodoptera frugiperda (SfP)-FasL cells in vitro resulted in the induction of apoptosis in germ cells detected by the TUNEL method. Fur thermore. DNA fragmented ladders were also demonstrated in germ cells co-in cubated with Sf9-FasL cells. CONCLUSION: Fas-FasL system seemed to play an apoptotic role in spermatogen esis by the molecular interaction between Fast on Sertoli cells and Fas on germ cells.