| SectionⅠThe effect of Jiaotaiwan on pancreatic lipid accumulation and islet cell apoptosis in a rat model of type 2 diabetesObjectiveTo investigate the effect of Jiaotaiwan on pancreatic lipid accumulation and islet cell apoptosis in a rat model of type 2 diabetes.MethodsThe rat model of type 2 diabetes was established by intravenous injection of small doses of streptozotocin and feeding a high-fat diet for 8 weeks.Rats in the treatment group were treated with Jiaotaiwan from gastric tube. Oral glucose tolerance test (OGTT), fasting serum insulin (FINS), free fatty acid (FFA) levels and lipid profiles were assayed. HOMA-IR was calculated. Serum vaspin concentration was determined by enzyme-linked immunosorbent assay (ELISA) . Pancreatic pathology was determined by hematoxylin-eosin staining and pancreatic triglyceride (TG) content was examined by lipid extraction method. The correlation analysis between vaspin and HOMA-IR, pancreatic TG content were performed. Pancreatic islet cell apoptosis was detected by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay (TUNEL).ResultsSerum vaspin concentration was positively correlated with HOMR-IR and pancreatic triglyceride (TG) content. The correlation coefficient was 0.631 and 0.603, respectively (P<0.01). Compared with the normal group, blood glucose, FINS, FFA levels,HOMR-IR were all elevated in the diabetic rats with obvious hyperlipidemia. Serum vaspin concentration was also increased. Pancreatic TG content was elevated in accordance with increased pancreatic islet cell apoptosis in diabetic rats(P<0.01). Compared with the model group, blood glucose, FINS, FFA levels,HOMR-IR were all reduced in the rats of Jiaotaiwan group. Meanwhile, serum vaspin concentration, pancreatic lipid accumulation and TG content were decreased as well as islet cell apoptosis was decreased in Jiaotaiwan group(P<0.01).ConclusionJiaotaiwan is effective on treating type 2 diabetes in rats. The mechanism may be related to reducing serum vaspin level,pancreatic lipid accumulation and islet cell apoptosis. SectionⅡThe Molecular Mechanism of 8-hydroxy-dihydro berberine on Treating Hyperlipidemia in RatsObjectiveTo investigate the molecular mechanism of 8-hydroxy-dihydro berberine (Hdber) on treating hyperlipidemia in rats.MethodsThe rat model of hyperlipidemia was established by feeding a high-fat-diet for 4 weeks.Then the rats were randomly divided into model group, berberine group, Hdber groups which were treated with different doses of Hdber, and simvastatin group. Rats in different treatment groups were given corresponding therapy from gastric tube. Meanwhile normal animals were set as control group. Blood lipid level including total cholesterol (TC), triglyceride (TG), high density lipoprotein-cholesterol (HDL-C) , low density lipoprotein-cholesterol (LDL-C), free fatty acid (FFA), apolipoprotein AⅠ(Apo-AⅠ) and apolipoprotein B (Apo-B) were detected. The protein expressions of low density lipoprotein receptor (LDL-R), sterol regulatory element binding protein 2 (SREBP-2), HMG-CoA reductase (HMGCR), and proprotein convertase subtilisin/kexin type 9 (PCSK-9) in liver tissues were determined by western blot.ResultsCompared with the control group high-fat-diet feeding elevated serum TC, TG, LDL-C, FFA, Apo-B as well as increased the expression of PCSK-9 protein in liver tissue in rats (P<0.01).Meanwhile, high-fat-diet feeding decreased HDL-C, Apo-AⅠand the expression of LDLR, SREBP-2 and HMGCR proteins in liver tissue. However, the addition of berberine and Hdber reversed the above changes (P<0.05 or P<0.01) without any effect on the expression of SREBP-2 and HMGCR proteins (P>0.05). Compared with the berberine group, no significant changes were found in all the above parameters in high and middle doses of Hdber groups, however in low dose group, TC, LDL-C, Apo-B and the expression of PCSK-9 protein were elevated while Apo-AⅠand the expression of LDL-R protein decreased significantly in comparison with berberine group(P<0.05,P<0.01). Compared with high dose group, TG, LDL-C, Apo-B and the expression of PCSK-9 protein were increased and Apo-AⅠand the expression of LDL-R protein were decreased in Hdber low dose group (P<0.05,P<0.01). Meanwhile, no significant differences were observed between Hdber high and middle doses groups.ConclusionIt is suggested that Hdber is effective on treating hyperlipidemia in rats. The mechanism may be associated with increasing expression of LDL-R protein and the decreasing expression of PCSK-9 protein in liver tissue. Hdber at high and middle doses exert better effect than low dose Hdber. |
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