Testicular toxicity and reproductive performance of streptozotocin-induced diabetic male rats: the ameliorating role of silymarin as an antioxidant

Abstract

Diabetes mellitus (DM) is a glucose, fat, and protein metabolism disorder. Testicular toxicity and reproductive dysfunction are consequences of streptozotocin (STZ)-induced diabetes. Oxidative stress has been suggested as one of the main mechanism involved in STZ-induced toxicity. Since many studies revealed that Silymarin (SMN), a plant extract, has anti-diabetic and antioxidant activity, this study was conducted to evaluate the effects of this natural agent on testicular function and male reproductive parameters in STZ-induced diabetic rats. Sperm parameters, in vivo reproductive performance, and oxidative stress markers were measured. In addition, relative expression of apoptotic-related genes and testosterone level were evaluated. STZ-induced diabetes altered sperm parameters, reduced reproductive performances, increased lipid peroxidation (LPO), and decreased antioxidant enzyme activities. Our results showed that SMN intake improved sperm parameters, reproductive performances, decreased LPO, and increased antioxidant enzyme activities. The relative mRNA expression of Bcl-2 was significantly reduced, and that of Bax, Caspase-3 was significantly increased in the diabetic rats compared to the control group. SMN significantly increased the expression of Bcl-2 and decreased the expression of Bax, Caspase-3. Serum levels of testosterone showed a significant decreased in diabetic rats, compared to the control group and serum testosterone levels revealed a significant increase in groups that received SMN. The protective potential of SMN against oxidative stress in STZ-induced testicular toxicity and its potential to improve fertility in diabetic rats makes it a potential candidate to reverse the toxic effect of diabetes on the testis by herbal antioxidants.