Apoptosis-related proteins in the testes of infertile men with varicocele.

Abstract

To assess immunohistochemically the expression of apoptosis-related proteins in the testes of infertile men, to determine which of these proteins were related to hypospermatogenesis, as a previous report suggested that apoptosis was suppressed in infertile men with varicocele. The expression of Bcl-2, Bax, caspase-1 (ICE) and caspase-3 (CPP32) were examined in bilateral testicular specimens from 26 infertile men with varicocele and six normal testicular specimens, using the avidin-biotin-peroxidase complex method. Clinical variables were also assessed. Bax, ICE, and CPP32 were expressed in germ cells, while Bcl-2 was not. Differences in staining in left or right testes were not significant. In both testes of infertile patients with varicocele, significantly fewer germ cells stained for CPP32 than in controls (P < 0.001). For Bax and ICE, total germ cell staining was similar between these groups. Staining was less frequent in infertile patients for both CPP32 and ICE when the analysis was restricted to spermatogonia. Serum luteinizing hormone levels correlated positively with CPP32 staining (P = 0.0457). The reduced expression of CPP32 participates in regulating apoptosis in the testes of infertile men with varicocele.