Introduction: Increased testicular germ cell apoptosis has been reported in varicocele-induced rats. We studied intrinsic or extrinsic pathway of apoptosis by detecting Bcl-2, caspase-9, caspase-8, and activated caspase-3 expressions in the bilateral testes of experimental varicocele-induced rats.
Materials and methods: Experimental left varicocele (ELV) was created by partial ligation of left renal vein in a study group of 24 adult male Sprague-Dawley rats. The other 24 rats were as control group. Eight rats from each group were killed at 4, 8, and 12 weeks following varicocele creation. Testicular tissues of both groups were sampled for TUNEL assay and immunoblotting.
Results: Increased apoptotic germ cell was found in the ipsilateral testis of varicocele group at 8 and 12 weeks after operation (P < 0.05). Increased activated caspase-3 expression in the contralateral (right) testis was noted at 12 weeks following varicocele creation (P < 0.05).
Conclusions: Our study demonstrates down-regulation of Bcl-2 expression and increased expressions of caspase-9 and activated caspase-3 in the ipsilateral testis of ELV rats at 8 and 12 weeks, indicating gradually increased testicular tissues apoptosis through the intrinsic pathway in varicocele-induced rats. Simultaneously, increased apoptosis in the contralateral testis was observed at 12 weeks (P < 0.05) following varicocele creation also.