AB256. Grape seed proanthocyanidin extract attenuates varicocele-induced testicular oxidative injury in rats by activating the Nrf2-antioxidant system

BACKGROUND: We investigated whether grape seed proanthocyanidin extract (GSPE) can attenuate varicocele-induced testicular oxidative injury through the Nrf2 antioxidant pathway. METHODS: A varicocele model was established by partial ligation of the left renal vein. RESULTS: After four weeks of GSPE administration, the decreased sperm count and motility and other pathological changes caused by varicocele were significantly alleviated, as indicated by the results of computer-assisted sperm analysis (CASA) and HE staining. Moreover, the decreased antioxidant enzyme (SOD and GSH-Px) activity and elevated oxidative stress level were partly reversed by administration of GSPE. Furthermore, the apoptotic level of the testis induced by varicocele was decreased by the GSPE treatment according to the TUNEL assay. Additionally, the expression of apoptosis-related proteins such as bcl-2, bax and cleaved caspase-3 were also affected by GSPE. GSPE also activated nuclear factor (erythroid-derived 2)-like 2 (Nrf2), which is a key antioxidative transcription factor, with elevation of the downstream factor hemeoxygenase-1 (HO-1). CONCLUSIONS: These findings suggest that GSPE can ameliorate abnormal spermatogenesis and testicular injury in varicocele rats, possibly due to its antioxidative activity and ability to activate the Nrf2 pathway.