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