| ObjectiveTo observe the effects of coptidis rhizome, rehmannia dride rhizome and their compatibility on insulin resistance (IR)and function of islet beta cell in type 2 diabetes mellitus rats so as to investigate mechanisms of coptidis rhizome, rehmannia dride rhizome and their compatibility, and explore their compatibility whether there are selective or synergistic effects on therapeutic targets and reveal further the scientific connotation of Rhizoma Coptidis Pill.MethodThe mode of type 2 diabete mellitus rats was induced by high fat fed and low dose Streptozotocin (STZ) (30mg/kg) injected through vena caudails. The diabetic rats were randomly divided into the following five groups: coptidis rhizome group, rehmannia dride rhizome group, coptidis rhizome + rehmannia dride rhizome group, rosiglitazone group and diabetic control group. Normal control group was also set up. Afer intervention for four weeks, oral glucose tolerance test (OGTT) and insulin release tests (IRT) were done on each group. The blood of each rat was collected via ophthalmic venous plexus at 0, 30, 60,120 and 180 min afer rats were anesthetized by the ether. After IRT finished, all rats were anesthetized. Blood was collected from aorta ventrail.Pancreas were immediately also dissected out. A portion of pancreatic tissues were put into 10% neutro-formalin solution for histopathological study and islet beta cells apopotosis detection. The other portions of pancreatic tissues were put into 2% glutaric dialdehyde for observation of islet beta cell ultrastructure. Blood glucose levels were tested by the means of gluocose oxidation enzyme. Serum insulin was tested by the means of radio-immunity. Serum IL-1β, IL-6 and TNF-αwere tested by enzyme-linked immunosorbent assay (ELISA).Serum FFAs were tested on spectrophotometer using commercial kits. Serum TG, TC, LDL-C, HDL-C were tested on semi-automatic biochemisty analysis apparatus using commercial kits.The areas under insulin curve(INSAUC) and insulin sensitivity index (ISI) were according to the following formulas: ISI = In1/ FBG (mmol/L)×FBI (mIU/L) INSAUC=(INS0'+INS180')/2+INS30'+INS60'+INS120'Results1. The effects of coptidis rhizome, rehamannia dride rhizome and their compatibility on OGTT, INSAUC and ISICompared to normal control group, the levels of blood glucose obtained 0, 30, 60, 120min in diabetic control group were significantly (P<0.01) higher. Compared to diabetic control group, the levels of blood glucose obtained 0,30,60,120min in all treatment groups were significantly(P<0.01)lower. Compared to compatibility of coptidis rhizome and rehamannia dride rhizome group, the levels of blood glucose obtained 0, 30, 60,120min in coptidis rhizome group and rehamannia dride rhizome group were significantly(P<0.01)higher.Compared to normal control group, diabetic control group had significantly(P<0.01)smaller INSAUC and lower ISI. Compared to diabetic control group, all treatment groups had significantly(P<0.01) bigger INSAUC and higher ISI. Compared to compatibility of coptidis rhizome and rehamannia dride rhizome group, INSAUC in coptidis rhizome group and rehamannia dride rhizome group were significantly(P<0.01)smaller and ISI in coptidis rhizome group and rehamannia dride rhizome group were were significantly(P<0.01)lower.2. The effects of coptidis rhizome, rehamannia dride rhizome and their compatibility on TG, TC, LDL-C and HDL-CCompared to normal control group, diabetic control group had significantly(P<0.01)higher serum TG, TC, LDL-C and lower serum HDL-C. Compared to diabetic control group, all treatment groups had significantly(P<0.01)lower serum TG, TC, LDL-C and higher serum HDL-C. Compared to compatibility of coptidis rhizome and rehamannia dride rhizome group, serum TG, TC, LDL-C in coptidis rhizome group and rehamannia dride rhizome group were significantly(P<0.01)higher and serum HDL-C in coptidis rhizome group and rehamannia dride rhizome group were significantly(P<0.01)lower.3. The effects of coptidis rhizome, rehamannia dride rhizome and their compatibility on serum IL-1β, IL-6, TNF-αand FFAsCompared to normal control group, the levels of serum IL-1β, IL-6, TNF-αand FFAs in diabetic control group were significantly(P<0.01)higher. Compared to diabetic control group, the levels of serum IL-1β, IL-6, TNF-αand FFAs in all treatment groups were significantly ( P<0.01 ) lower. Compared to compatibility of coptidis rhizome and rehamannia dride rhizome group, the levels of serum IL-1β, IL-6, TNF-αand FFAs in coptidis rhizome group and rehamannia dride rhizome group were significantly(P<0.01)higher.4. The effects of coptidis rhizome, rehamannia dride rhizome and their compatibility on the expression and secretion of insulin and apopotosis of islet cellCompared to normal control group, MOD in diabetic control group was significantly(P<0.05)lower. Compared to diabetic control group, MOD in all treatmet groups were significantly (P<0.05)higher. Compared to compatibility of coptidis rhizome and rehamannia dride rhizome group, MOD in coptidis rhizome group and rehamannia dride rhizome group were significantly(P<0.05)lower.Compared to normal control group, apopotosis rate of islet cell in diabetic control group was significantly(P<0.05)higher. Compared to diabetic control group, apopotosis rates of islet cell in all treatment groups were significantly (P<0.05)lower. Compared to compatibility of coptidis rhizome and rehamannia dride rhizome group, apopotosis rate of islet cell in coptidis rhizome group and rehamannia dride rhizome group were significantly(P<0.05)higher.Observation of ultracmicrostructure showed that the cell nucleus of islet beta cells in normal control group was orbicular-ovate, with chromoplasm well-distrbuted. The structures of endocytoplasmic reticulum and chondriosome in cytoplasm were lampros, with a large number of intensive secretion granules enclosured by coronas. Elder piths of different density were in granules, with a transparence strap between elder pith and coronas. The cell nucleus in diabetic control group was smaller, with chromatospherite abolition and chromoplasm aggregation. Fat drop deposited in cytoplasm. There were few secretion granules distributed rarefaction, with a increased distance between elder pith and corona, and even coronas fractured and fused. The cell nucleus in coptidis rhizome group was obform with chromoplasm aggregation. Secretion granules were significantly increased, distributed tightly and bigger. Fusion of coronas was significantly decreased. The cell nucleus in rehamannia dride rhizome group was lampros, with chromatospherite and chromoplasm well-distributed. Fat drop deposited in cytoplasm. Secretion granules were no significantly increased, with distributed rarefaction. Fusion of coronas was also no significant decreased. The cell nucleus in coptidis rhizome + rehamannia dride rhizome group was lampros, with chromatospherite and chromoplasm well-distrbuted. Rough endocytoplasmic reticulum in cytoplasm was also lampros. Secretion granules in cytoplasm were significantly increased, distributed tightly and bigger. Fusion of cornoas was significantly decreased. The cell nucleus in rosiglitazone group was lampros. Secretion granules in cytoplasm were smaller and distributed tightly. Fusion of cornoa was no significant.Conclusion1. Coptidis rhizome, rehmannia dride rhizome and their compatibility are effective on treating type 2 diabetes mellitus rats. The effect of their compacibility is better than the single-drug.2. The effective mechanisms of coptidis rhizome, rehmannia dride rhizome and their compatibility lie in decreasing the levels of inflammatory cytokine to improve insulin resistance and inhibiting apopotosis of islet cells to protect islet beta cell.3. The effects of compatibility of coptidis rehizome and rehmannia dride rhizome on decreasing the levels of inflammatory cytokine and inhibiting the apopotosis of islet cell are better than single-drug, which infer there were synergetic effects on the two therapeutic targets for their compatibility ,and reveal further the scientific connotation of Rhizoma Coptidis Pill. |
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