OBJECTIVETo investigate the effects of experimental left varicocele (ELV) on the cystatin-related epididymal spermatogenic (CRES) protein in the testis and epididymis of adolescent rats.

METHODSThe ELV model of Sprague-Dawley (SD) male adolescent rats was established, and the expression of CRES protein in the testis and epididymis was detected by immunohistochemistry and Western-blot at 2 and 4 weeks after surgery.

RESULTSImmunohistochemistry and Western-blot detected CRES protein in both the testis and the epididymis of the ELV rats and the control rats. Immunohistochemistry showed that within the testis, CRES protein was expressed mainly in the cytoplasm of round spermatids and elongating spermatids, sperm acrosomes and residual bodies. The expression was most intensive at Stages I-III and IX-XIV, and then decreased gradually at Stages VII-VII and IV-VI. Within the epididymis, CRES protein was expressed mainly in the cytoplasm of the principal cells of epididymal epithelia. Western-blot detected CRES protein in Mr 19,000 and 14,000, stronger in the former than in the latter. Image and statistical analyses showed that the expression of CRES protein in the 2-week and 4-week ELV groups was significantly higher than in the control group (P < 0.05, or P < 0.01).

CONCLUSIONCRES protein expressed in both the testis and epididymis of adolescent rats and the expression is stage-specific and cell-specific in the testis and segment-specific and cell-specific in the epididymis. The expression of CRES protein in the ELV rats is much stronger than in their corresponding controls. It is suggested that CRES protein may be significantly involved in the regulation of spermatogenesis and sperm maturation, and possibly associated with varicocele-related male infertility or subfertility.