Effect of varicocelectomy treatment on spermatogenesis and apoptosis via the induction of heat shock protein 70 in varicocele-induced rats

In the current study, the hypothesis that testicular varicocelectomy improves spermatogenesis and attenuates apoptosis via the induction of heat shock protein 70 (Hsp70) in a rat model of varicocele was investigated. Adult male Wistar rats (n=75) were randomly divided into 5 groups of 15 each: Control, sham, varicocele, varicocelectomy, and varicocelectomy plus Quercetin. A total of 6 weeks after the varicocelectomy, the left testis of all rats was removed for subsequent examination. Histological changes were compared between the groups. The expression of Hsp70 and apoptosis-associated indicators were evaluated based on immunohistochemical, western blot and mRNA expression analyses. Compared with the varicocele group, the varicocelectomy group exhibited a markedly reduced Bcl-2-associated X protein/B-cell lymphoma 2 (Bax/Bcl-2) ratio, and had a decreased expression of caspase-9, cytochrome c (cyt c) and caspase-3 through the intrinsic signal transduction pathways. Quercetin treatment inhibited the protective effects of varicocelectomy. The expression of Hsp70 was increased in the varicocele group which was further elevated by the varicocelectomy. These results indicated that varicocelectomy can reduce the Bax/Bcl-2 ratio, and decrease the levels of caspase-9, cyt c and caspase-3 via the mitochondrial signal transduction pathway. Such protective effects on left testis spermatogenesis and against apoptosis may be due to the induction of Hsp70. The findings of the present study suggested that varicocelectomy has a clear advantage in protecting testicular function and ameliorating spermatogenic cells apoptosis.