Beneficial effects of quercetin on sperm parameters in streptozotocin-induced diabetic male rats.

Quercetin (QR) is a strong antioxidant and has been shown to reduce oxidative stress in the long-term treatment of streptozotocin (STZ)-induced diabetes in animal models. Antioxidants have significant effects on spermatogenesis, sperm biology and oxidative stress, and changes in antioxidant capacity are considered to be involved in the pathogenesis of chronic diabetes mellitus. The present study aims to examine the influence of QR on spermatogenesis in STZ-induced diabetes in male Wistar rats. Animals (n = 50) were allocated into five groups: Group 1: Control rats given 0.5 ml of 20% glycerol in 0.9% normal saline. Group 2: Control rats given buffer (pH4.0).Group 3: diabetic controls. Group 4: rats given QR 15 mg/kg/day (i.p.). Group 5: STZ + QR rats. Animals were kept in standard conditions. At the end of the experiment (28th day), blood samples were taken for determination of testosterone, total antioxidant capacity, and levels of malondialdehyde and oxidized low-density lipoprotein. All rats were euthanized, testes were dissected out and spermatozoa were collected from the epididymis for analysis. Sperm numbers, percentages of sperm viability and motility, and total serum testosterone increased significantly in QR-treated diabetic rats (P < 0.05) compared with control groups. In histopathology, degeneration and inflammation in testes cells associated with diabetes were improved and testes weights in the QR-treated diabetic group decreased significantly in comparison with controls (P < 0.05). We conclude that QR has significant beneficial effects on the sperm viability, motility, and serum total testosterone and could be effective for maintaining healthy sperm parameters and male reproductive function in diabetic rats. Copyright 2010 John Wiley & Sons, Ltd.