| Objective:To investigate the prevention and treatment effect of nicotinamide on the diabetic rats,and approach the oxidative stress mechanism of action.Methods:Type 1 diabetic rat model was induced by a single injection of streptozotocin(45mg/kg body weight)via tail vein.Four groups with eight mice each randomly were used:control,diabetes,using nicotinamide(1g/kg body weight) 3days before injection of streptozotocin and diabetes with nicotinamide treatment(1 g/kg body weight)after 3 days of injection,plasma glucose were examined for rats in each group in 3d,5d,10d.We alse examined blood MDA content by spectrophotometer for every rat in 3d.Rats in each group were sacrificed at two time points:5d,10d after the beginning of test.Half of rats in every group were sacrificed every time.At the same time,the blood MDA content,blood insulin and MDA content,Mn-SOD activity of pancreatic tissue were examined.The insulin proteins of mice pancreas tissue were detected by immunohistochemical method.Insulin in beta cells of islets was detected with immunohistochemical analyses and analysed with image analyzer. Three index had been observed,they were area,mean density and IOD.Results:1 blood glucose:Compared to those of control group and nicotinamide prevention group,the blood glucose of rats in diabetes group and nicotinamide treatment group were significantly increased(P＜0.01),The levels of plasma glucose showed no difference between diabetes group and nicotinamide treatment group (P＞0.05).The same results could be observed between control group and nicotinamide prevention group(P＞0.05).2 plasma insulin:In 5 day of test,there were no statistical differences in plasma insulin among all animals(P＞0.05).But in 10 day of test,the blood insulin level of control group was significantly higher than those of other 3 groups(P＜0.01).3 the indexes related oxidative stress:Mn-SOD,MDA.Remarkably higher blood MDA concentration was observed in nicotinamide treatment group,compared to control rats(P＜0.01).Compared to diabetes group,blood MDA concentration of control group showed a significant reduction.The activities of Mn-SOD of rat pancreatic tissue in nicotinamide prevention group are increased statistically than that of nicotinamide treatment group(P＜0.01).Pancreatic tissue MDA concentration of diabetes rats was remarkably higher than that of control group.4 Immunity Histochemistry results:Insulin content of beta cells of rats in nicotinamide prevention group and control group were statistically higher than those of diabetes rats and nicotinamide treatment group(P＜0.01).There was not remarkably difference between nicotinamide prevention group and control group(P＞0.05).The levels of Insulin content showed no difference between diabetes group and nicotinamide treatment group(P＞0.05).Statistical difference of insulin content had been observed between diabetes group and control group(P＜0.05).Conclusions:1 Prophylactic utilization of antioxidant nicotinamide could reduce fasting blood glucose by protection of pancreaticβ-cells in STZ-induced diabetes rats.2 Decreased superoxide diamutase activity,Increased peroxidize lipide and oxidative stress may be found in the beta cells of STZ-induced diabetes mice.3 Nicotinamide could reduced the injure of beta cells.Increased free radical and peroxidize lipide,decreased antioxidase activity may be part of the mechanism of protecting beta cells by nicotinamide in STZ-induced diabetes mice.4 It is not remarkably useful to use nicotinamide in the rats whose blood glucose has increased. |
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