| The increasing prevalence of diabetes is a worldwide health problem. Impaired insulin secrection capacity is demonstrated that plays an important role in the occur and development of diabetes mellitus (DM). HBCI is often used to measure insulin secretion capacity of pancreatic islets. In resent years, Nitric oxide (NO) has been demonstrated playing an important role in the development of DM with the reaserch of DM on the mechanism .NO is relative to the destruction of pancreatic islets β cells which makes the deline of β cells' insulin secretion capacity.The present study investigated the effect of aerobic training on the level of NO, the activity of total NOS and iNOS in pancreatic islets, the insulin secretary capacity of β cells in rats induced by Streptozotocin (STZ) into insulin dependent diabetes mellitus (IDDM) model, in order to discuss the other possible mechanism of aerobic training in improving the insulin secretary capacity of diabetic rats islets β cells. Therefore, the study may provide evidences for diabetic motortherapy and reference to medicine treatment with inhibitors of NOS for diabetic patients.12 rats were randomly selected from 60 male SD rats as normal group and divided into two groups: normal control group (Nc) and normal exercise group (Ne). The rest were induced by STZ into diabetic model as DM group and divided into two groups: DM exercise group (DMe) and DM control group (DMc). Animals were trained with swimming in Ne and DMe, 60 min/day and 6 days/week for 6 weeks. The body weights of rats'pre and post experiment were recorded. Serum insulin, serum glucose, the concentration of NO and the activity of TNOS and iNOS in pancreatic islets of animals were measured. Moreover, the increasing amount of daily body weight on average and HBCI assessed the insulin secretion were computed.The results were as follow:(1) The daily body weight of rats in DMe was significantly increased compared with that of DMc during 6 weeks training (P<0.05).And the daily body weight of diabetic rat were all lower than that of rats in Nc group (P<0.01).(2) The content of serum glucose of rats in DMe was significantly decreased compared withthat of DMc. And compared with itself, the content of serum glucose of DMe also decreased significantly after 6-week training period (P<0.01). There was a significant difference in the level of serum insuin between diabetic rats and normal rats. No difference was observed within diabetic rats. But it is significantly different in HBCI at the level of 0.01 between DMc and DMe (P<0.01). In addition, the contentration of serum insulin in rats of Ne is lower than that of Nc significantly (P<0.01).(3) The concentration of NO in islets was significantly lower in diabetic rats of DMe than that of DMc (F<0.01). And there was a difference between diabetic rats and normal rats at the level of 0.01. At the same time, an increase in the level of NO in islets tissue was found between Nc and Ne (P<0.01).(4) After 6-week swimming training, compared to DMc, the activities of total NOS and iNOS in pancreatic islets of DMc were delined (P<0.05).(5) Statistical analysis showed that there was a negative correlation in the level of NO and HBCI in diabetic rats (r=-0.583, P<0.05). A positive correlation was in exitence in the activity of iNOS and TNOS of diabetic rats (r=0.812, P<0.01) and there was also a positive correlation found in the activety of iNOS and the concentration of NO in pancreatic islets in diabetic rats (r=0.732, P<0.01).Conclusion: The results suggest that aerobic training improves insulin secretary capacity of P cells through decreasing the production of NO in islets. It is proably relative to that exercises may shown a protective effect by lessening (3 cells' damage imposed on by excess NO synthased by iNOS. |
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