Nonetheless, the insulin stimulatory effect of MAE could not be observed in cell culture using insulinema cell line.19 In the present study, reduced GPx and GR activities and TAC as well as enhanced MDA levels clearly confirm the presence of high testicular oxidative stress in diabetes. Consistent with our results, a significant reduction in GPx and GR activities #check details randurls[1|1|,|CHEM1|]# in the testis of diabetic rats has been reported by other researchers.20,21 However, the level of TAC was not evaluated in the previous studies. Our results demonstrated that the administration of MAE to diabetic rats restored TAC and enzymes activities and decreased MDA levels. These
Inhibitors,research,lifescience,medical effects of MAE are probably due to its hypoglycemic and free radical scavenging properties.
MAE contains several compounds such as flavonoids glycoside that can act as a potent antioxidant.22 The role of oxidative stress in the development of testicular dysfunction under diabetic condition is not well understood. Unlüçerçi et al.23 found that Inhibitors,research,lifescience,medical oxidative stress was not involved in possible testicular complication of diabetes. In contrast, the results of a study by Shrilatha et al.24 suggested that oxidative stress might contribute to the Inhibitors,research,lifescience,medical induction of testicular dysfunction and reduced fertility of diabetic animals. In the present study, we observed significantly lower levels of free Ts in the diabetic rats. MAE treatment increased free Ts levels by 61% as compared to the diabetic rats. Nevertheless, this value was still lower than that in the control group. In the previous studies, a drop in total Ts was reported in diabetic rats.20,25 Since the concentration of total Ts depends on the serum level of albumin and sex-hormone binding globulins, measuring free Ts is a more sensitive indicator of Ts status. To the Inhibitors,research,lifescience,medical best of our knowledge, there is no report on the androgenic activity of MAE in the literature. In order to determine the likely mechanism
of MAE action on Ts levels, we analyzed the mRNA expression level of two key steroidogenic proteins, namely StAR and P450scc. StAR is a protein that mediates the rate-limiting Inhibitors,research,lifescience,medical step in all steroid production. StAR participates in the transport of substrate cholesterol from the mitochondrial CYTH4 outer membrane to the inner membrane, where P450scc is located. The first committed step in the synthesis of steroid hormones is the conversion of cholesterol to pregnenolone, catalyzed by P450scc.7 Our results showed that the expression of StAR gene was significantly (60%) decreased in the diabetic group in comparison with the control. The mRNA expression of P450scc was also decreased, but it was not statistically significant. The MAE-treated diabetic rats showed induction of both mRNA levels, but a marked increase was only observed for StAR. It has been shown that oxidative stress can damage the key molecules of steroidogenic pathway, including StAR and cytochrome P450 enzymes in rat leydig cell culture.