Roles of Fas/FasL-mediated apoptosis and inhibin B in the testicular dysfunction of rats with left-side varicocele

Summary We investigated the role of the Fas/FasL signalling pathway and inhibin B expression in rats with an experimentally induced left-side varicocele. Forty-five Sprague Dawley (SD) male rats were randomly divided into three groups in average: control group, sham group and experimental group. The expression of inhibin B in the rat left testis was analysed at the mRNA and protein levels by reverse transcription–polymerase chain reaction (RT-PCR) and Western blotting respectively. The expressions of Fas, FasL and caspase-3 in the left testis were measured by RT-PCR and immunofluorescence. The apoptosis index (AI) was measured by terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL). Both the mRNA and protein of inhibin B were significantly reduced in the experimental group compared with that in the control group or the sham group. The expression of Fas, FasL and caspase-3 in the experimental group was significantly increased compared to that in the control group or the sham group. The concentration of serum inhibin B was also inversely related to circulating FSH concentrations and positively correlated with sperm count. It is concluded that Fas/FasL system may play an important role in apoptosis of rats with experimental varicocele and inhibin B could reflect spermatogenesis function.