OBJECTIVETo investigate the effects of experimental left varicocele (ELV) on the vascular endothelial growth factor (VEGF) and its receptor fms-like tyrosine kinase-1 (Flt-1) proteins in the testis and epididymis of adolescent rats, and to find out the correlation of the two proteins with varicocele-induced male infertility.

METHODSWe established the ELV model in adolescent male SD rats, and detected the expressions of VEGF and Flt-1 proteins in the testis and epididymis by immunohistochemistry at 2 and 4 weeks after surgery.

RESULTSCell- and region-specific expressions of VEGF and Flt-1 were observed in the testis and epididymis of the ELV and control groups. Statistical analysis showed that, in comparison with the corresponding control groups, the 2- and 4-week ELV groups exhibited a notable increase in the VEGF protein expression in the hibateral testis and epididymis (P < 0.01, P < 0.05); the Flt-1 expression was obviously upregulated in the hibateral testis and epididymis of the 2-week ELV group (P < 0.01, P < 0.01), but remarkably reduced in the hibateral testis and left epididymis of the 4-week ELV group (P < 0.01, P < 0.05), with no statistic difference in the right epididymis (P > 0.05).

CONCLUSIONELV can cause changes in the expressions of VEGF and Flt-1 proteins in the testis and epididymis of adolescent rats, and consequently affect spermatogenesis and spermiotelcosis, which may be one of the causes of varicocele-induced male infertility or subfertility.