Effects Of Huanglian Jiedu Decoction And Berberine On Phosphatidylinositol-3-Kinase MRNA And Protein Expression In Insulin Targeted Tissues Of Type 2 Diabetic Rats

【Objective】To investigate the effects of Huanglian Jiedu decoction and berberine on the mRNA and protein expression of phosphatidylinositol-3-kinase in muscular, fatty tissues and the liver in type 2 diabetes mellitus (T2DM) rats and explore their possible molecular mechanism of improving IR.【Methods】The male Wistar rats were induced to establish murine model with type 2 diabetes mellitus (T2DM) by the injection with streptozotocin (STZ, 30mg/kg) through tail vein and the feeding with high fat and high caloric diets. The injected animals were randomly divided into Huanglian Jiedu decoction group (HLJD), berberine group (BER), aspirin group (ASP) and model group (MOD), meanwhile a group of normal animals without any treatment was set up for normal control (NOR). The animals in the former three groups were treated for 10 weeks with experimental preparations which was adjusted each week according to the murine body weight. The following indexes were also detected.1. Basic biochemical parameters for diabetes: Fasting blood serum glucose (FBG) level and oral glucose test (OGTT) were determined by glucose oxidase method before and after the rats were treated for 10 weeks, while fasting serum insulin (FINS) level were measured by radio-immunity after they were treated for 10 weeks.2. The mRNA expression of phosphatidylinositol-3-kinase (PI-3K) in the target tissues were detected by RT-PCR, and the protein expression of PI-3K were measured by Western-blot as well.【Results】1. FBG and OGTT: After the animal modeling and before the drug intervention, the levels of FBG and OGTT in four treated groups were significantly higher than those in NOR group (P<0.05), while there was no difference among the four treated groups. But after the modeled rats were treated for 10 weeks, FBG levels of NOR group and HLJD group were apparently lower than those of MOD group (P<0.05), further OGTT levels of ASP, HLJD and NOR groups decreased obviously as compared with those of MOD group (P<0.05).2. FINS: The level of FINS in ASP group increased as compared with that in MOD group (P<0.05). But the levels of FINS of HLJD and BER groups decreased significantly in comparison with NOR group (P<0.05), and not significantly different from MOD group.3. The mRNA expression of PI-3K elevated significantly in skeletal muscular and adipose tissues in HLJD and BER groups as compared with those in MOD group (P<0.05).4. The protein expression of PI-3K in liver, skeletal muscular and adipose tissues in HLJD and BER groups were higher than those in MOD group (P<0.05). 【Conclusion】Huanglian Jiedu decoction and berberine could increase the levels of the mRNA and protein expression of PI-3K in the insulin targeted tissues before and after insulin stimulation, through which they could alleviate insulin resistance in diabetic rats. It is suggested that PI-3K might be one of the targeting points through which Huanglian Jiedu decoction and berberine could improve insulin sensitivity and decrease blood glucose level in insulin resistant animals.