Evaluation of heat-shock protein A2 (HSPA2) in male rats before and after varicocele induction.

Abstract

Varicocele is a major cause of infertility and may impair spermatogenesis. This study evaluated the molecular consequences of varicocele on the induction of heat-shock proteins, intracellular chaperones involved in stress responses, and of the ubiquitin-proteasome system, which is participates in the removal of defective sperm in the testis and epididymis. Wistar rats were randomly divided into three groups: surgically induced left varicocele, sham-operated, and untreated controls. Two months after surgery, we observed significantly reduced sperm parameters, DNA integrity, and protamine content in the sperm retrieved from the left epididymis compared to the right epididymis in the varicocele group, as well as compared to sperm retrieved from the left epididymis of the sham and control groups. According to Western blot analysis, we observed significantly higher HSPA2 expression in testicular tissue from the left testis compared to the right testis in the varicocele group or the left testis of the control group. Immunohistochemical analysis showed that expression of HSPA2 was higher in the round spermatid and sperm from the left varicocele compared to the control group. There was normally less HSPA2 expressed in the caput and corpus compared to the cauda of the epididymis in the control group, but this pattern was altered in the caput epididymis of the varicocele group. Levels of ubiquitination were also remarkably lower in the left testis of the varicocele group. Therefore, varicocele impacts expression of HSPA2 and ubiquitination.