| Objective:To observing the effect of insulin on the expression of index related to oxidative stressin the testes of type 1 diabetic rats, and to explore the protective mechanisms of insulin on the testis of diabetic rats.Methods:Twenty-eight male Sprague-Dawley(SD)rats were randomly divided into normal control group(group A,n=8) and diabetic model group(n=20).Type 1 diabetic model was established by a single intraperitoneal injection of streptozotocin of 65mg/Kg. Sixteen successfully-induced diabetic rats were randomly divided into diabetic control group(group B,n=8) and diabetic with insulin treatment(group C,n=8). Rats in group B were given protamine-zinc insulin by subcutaneous injection in does of 3~5U once daily to control blood glucose at 10mmol/L level.The other two groups were given similar dose of normal saline daily. At the end of the eighth week of experiment, rats were sacrificed after blood samples were collected, and then the bilateral testes,epididymis were took out quickly. Blood samples were used to detect the levels of blood glucose and testosterone. Testes weight were counted. The activity of superoxide dismutase(SOD)was assayed by the method of xanthine oxidase. The m RNA expression of testicular superoxide dismutase(SOD)1, nuclear factor E2-related factor2(Nrf2), NADPH: quinine oxidoreductase(NQO1), heme oxygenase-1(HO-1), nicotinamide adenine dinucleotide(NADPH) oxidase subunit p22 phox and p47 phox were assessed by real-time fluorescent quantitative PCR. The protein expressions of testicular Nrf2, NQO1, HO-1, p22 phox were analyzed by Western blot.Results:1.The levels of blood glucose and the expression of testicular p22 phox were significantly increased in group B than those in group A(P<0.05).2.The level of testosterone, testes weight, sperm number and motility, Nrf2, NQO1,HO-1 and SOD were significantly decreased in group B than those in group A(P<0.05).3. Above changes could be reversed by insulin treatment.Conclusion1.The increased expression of testicular p22 phox and the decreased expression of testicular Nrf2 and its downstream antioxidant molecules may lead to the elevated oxidative stress in the testes in diabetic rats, which may promote the occurrence and development of testopathy in diabetic rats.2.Insulin may play a protective role on testicular tissues by up-regulating the expression of Nrf2 and its downstream antioxidant molecules and down-regulating the expression of p22 phox to relieve the testicular tissues damage caused by oxidative stress in diabetic rats. |
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