Effect Of Insulin On The Expression Of Adiponectin And Its Receptors, AMPK, AKT And ENOS In The Testes Of Type 1Diabetic Rats

Objective:Observe the expression of adiponectin, adiponectin receptors, signaling pathways mediated by adiponectin receptors, and inflammatory cytokines in the testes of type 1diabetic rats, before and after insulin treated. To explore the possible effect of insulin on the expression of adiponectin,adiponectin receptors, and adiponectin receptor-mediated signaling pathways in the testes of type 1 diabetic rats.Methods:Thirty male Sprague-Dawley(SD)rats were randomly divided into normal control group(group A, n=8) and diabetic model group(n=22). 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 biochemical index, insulin and sex hormone(T, LH, FSH). Testes weight, sperm number and motility were also counted. The expression of testicular adiponectin,adiponectin receptors, adenosine 5’-monophosphate(AMP)-activated protein kinase(AMPK), protein kinase B(AKT), endothelial nitric oxidesynthase(e NOS), nitric oxide(NO), interleukin-6(IL-6), and tumor necrosis factor alpha(TNF-α) were assayed. Statistical analysis was performed by using LSD-t test and one way ANOVA.Results:1. There was significant pathological changes in the testes in group B rats than that in group A.2. The level of blood glucose, lipids, IL-6, TNF-α, the ratio of p-AKT to AKT, e NOS and NO in the testes were significantly increased in group B than those in group A(P<0.05).3. However, the level of plasma insulin and adiponectin, serum and testicular testosterone, testes weight, sperm number and motility, adiponectin and its receptor 1, and the ratio of p-AMPK to AMPK were significantly decreased in group B than those in group A(P<0.05).4. Above changes could be reversed by insulin treatment.Conclusions:1. Type 1 diabetes can produce significant pathological changes in rats’ testes.2. Adiponectin, adiponectin receptors, signal pathways’ indicators mediated by adiponectin receptors(AMPK, AKT, e NOS, NO) and inflammatory cytokines(IL-6, TNF-α)were all changed in diabetic rats’ testes. They may play important roles in the testicular injury in type 1 diabetic rats.3. Insulin reversed above indicators numerical value. Insulin may reduce the injury degree on testes and play protective roles on testicular tissues in diabetic rats by regulating the expression of adiponectin,adiponectin receptors and its signal pathways.