| Objective To study the influence of trichsanthes root powder(TRP) on blood glucose and blood lipidst in the diabetic rats, analyse the relationship between the hypoglycemic effect and the dose, and clarify the mechanism of therapeutic effect generatation.Methods 80 SPF male Wistar rats with the weight of(180±20)g were given normal forage adaptively for 7 days. According to the random number table, 10 rats were selected randomly to form normal group and were given normal forage. With high fat forage diet of four weeks, the rest 70 rats were injected with 36mg.kg-1 of streptozotocin(STZ) intraperitioneally to establish rats model. According to the random number table, 60 rats were selected randomly from the 68 model rats and were randomly divided into 6 groups,a group with 10 rats.One group was regarded as model group and other 3 groups were separately fed low (2g.kg-1),middle (4 g.kg-1), high dose (6 g.kg-1) of TRP, another 2 groups were separately fed metformin hydrochloride and ginseng-astragalus hypoglycemic granule by way of ig. The fasting blood glucose(FBG) and weight of the rats were measured before ig and after ig eight weeks. Finally blood was obtained from aorta of rats.Fasting blood glucose(FBG), triglyceride(TG), totalcholesterol(TC), high density lipoprotein(HDL), low density lipoprotein(LDL), glycosylated hemoglobin(HbAlc) and insulin(Ins)were tested. Pancreatic tissue and kidney of diabetic rats were stained by HE staining , which pathological changes were observed. Insulin receptor substrate-2(IRS-2) was the observation to pancreatic tissue and transforming growth factor(TGF-β1) was the observation to kidney, which were stained by immunohistochemistry staining.The expression of both observations in the rats of each group was observed.The influence of different dose TRP on blood glucose, blood lipids,weight, HbAlc and Ins in the diabetic rats was evaluated and the mechanism of therapeutic effect generatation was clarified.Results 1 The weight change of diabetic rats The weight of model rats began to reduce,whereas the weight of normal rats constantly increased.Compared with model group, the weight of therapy group rats was similar with model group before treatment(P>0.05); the weight of each dose of TRP group continued to decline in rats after treatment, there was no difference in weight(P>0.05). It showed that TRP could not change the trend of weight loss in diabetic rats.2 The influent on blood glucose of diabetic rats Before treatment, the blood glucose of each therapy group rats was similar with model group(P>0.05). After treatment, compared with model group, the blood glucose of high and low doses of TRP group significantly declined(P<0.01),while the blood glucose of middle dose of TRP group didn't significantly decline(P>0.05); Which showed that low and high doses of TRP could reduce blood glucose in type 2 diabetic rats,and the low dose of TRP was the stronger while the effect wasn't significant in middle dose of TRP group.Therefore,there wasn't dose-effect relationship between the hypoglycemic effect of TRP and the dose.3 The influent on blood lipids of diabetic rats Compared with model group,after treatment, totalcholesterol of each group all decreased, the high (P <0.05),middle,low dose of TRP group and the metformin hydrochloride group, the ginseng-astragalus hypoglycemic Granule group were significantly different(P<0.01); compared with model group,triglyceride and low density lipoprotein of each group both decreacsed(P<0.01),while high density lipoprotein increased(P<0.01). It showed that TRP could reduce blood lipids in type 2 diabetic rats:decreased triglyceride,totalcholesterol and low density lipoprotein, and increased high density lipoprotein.4 The influent on glycosylated hemoglobin of diabetic rats Compared with model group, except middle dose of TRP group(P<0.05), glycosylated hemoglobin of each group decreased obviously, the difference was significant(P<0.01); which showed that low and high doses of TRP could reduce glycosylated hemoglobin in type 2 diabetic rats while the effect wasn't significant in middle dose of TRP group.5 The influent on Insulin of diabetic rats Compared with normal group,the insulin level of model group in rats increased obviously(P <0.05); compared with rats of model group , except middle dose of TRP group,the insulin content in rats of rest group increased obviously(P <0.01). It suggested that low and high doses of TRP could increase insulin content in type 2 diabetic rats, while the effect wasn't significant in middle dose of TRP group,further suggesting that the hypoglycemic mechanism was related to stimulating insulin secretion.6 The pathological changes of pancreatic tissue Comparing with the model group, the islet of low and high dose TRP group were bigger in size ,and their quantity increased, besides that the count of pancreaticβcell increased.And IRS-2 expression in the pancreas tissue of low and high dose TRP group was also significantly increased compared with model group.7 The pathological changes of kidney Compared with model group, the pathological change of glomerular and tubular in low and high doses of TRP group has been reduced, while TGF-β1 expression in the kidney tissue of low and high dose TRP group was also significantly decreased. Conclusion 1 TRP had hypoglycemic effect and hypolipidemic effect on type 2 diabetic rats,which reduced blood glucose and glycosylated hemoglobin , decreased triglyceride , totalcholesterol and low density lipoprotein, and increased high density lipoprotein and insulin content ,in type 2 diabetic rats .2 There wasn't dose-effect relationship between the hypoglycemic effect of TRP and the dose.3 The hypoglycemic mechanism of TRP was probably related to preserving pancreatic tissue and stimulating insulin secretion. The deeper hypoglycemic mechanism of TRP might be involved in the up-regulation of IRS-2 expression in pancreatic tissue.4 TRP can reduce the overexpression of TGF-β1 in the kidney, and play a protective role in kidney of diabetic rats... |
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