Survivin downregulation is associated with vasectomy-induced spermatogenic damage and apoptosis.

OBJECTIVE To evaluate the expression of the apoptotic genes survivin, Bax and Bcl-2 in vasectomized rabbits and to determine their relation with vasectomy-induced spermatogenic impairment and germ cell apoptosis. MATERIALS AND METHODS Twelve adult rabbits (6-12 months old) were divided into three groups: sham control, unilateral vasectomy or bilateral vasectomy. Six months after vasectomy, testicular tissue was analyzed for germ cell apoptosis and DNA fragmentation by the TUNEL assay and gel electrophoresis, respectively. Spermatogenesis was assessed using the Johnsen score. The relative gene expression of survivin, Bax and Bcl-2 was measured using reverse transcription followed by real-time PCR. RESULTS Compared to sham animals, a significant decrease in testicular survivin mRNA levels was measured in the two vasectomy animal groups (p < 0.05). This was accompanied by a significant increase in the Bax:Bcl-2 ratio in the vasectomized animals (p < 0.05). In addition, these data showed positive correlation with enhanced apoptotic index, damage to spermatogenesis and DNA fragmentation after vasectomy. CONCLUSION These findings demonstrate that vasectomy-induced damage to spermatogenesis due to testicular apoptosis may be associated with survivin downregulation and Bax overexpression.