Effects Of Qingqianliushuanggua Tea On Decreasing Blood Glucose And Lipid In Type 2 Diabetic Rats And Its Mechanisms

Objective:To investigate effects of Qingqianliushuanggua tea?QSG?on decreasing blood glucose and lipid in type 2 diabetic rats induced by high-fat and high-sugar diet?HFD?and STZ and its mechanisms.Methods:Eighty Sprague Dawley?SD?rats,male,ten male rats were selected into control group,and fed with regular chow for 75 days,the other rats were fed with High-fat and High-sugar feed diet for 75 days,on day42,the rats except the control group were intraperitoneal injected of streptozotocin?STZ?by 35mg·kg^-1 to established the type 2 diabetic Model.Five days later,after fasted for14¹6 h with free access to water,the fasting blood-glucose?FBG?in rats were measured by Roche's blood glucose meter.Fifty type 2 diabetic rats with level of blood glucose between 11.0-28.0 mmol·L^-1 were selected and randomly divided into five groups:Model,Metformin(268 mg·kg^-1)and three QSG groups(1575,3150,6300 mg·kg^-1).Rats in Control and Model group were oral treated with pure water by 10 mL·kg^-1,and rats in Metformin group and QSG groups were oral treated with different concentrations of Metformin or QSG by10 mL·kg^-1,all the rats were oral treated once daily for twenty-eight consecutive days.Daily observed indexes as general clinical symptoms,diet status,drank water,and excretion of each rat were observed and recorded.Bodyweight and FBG of rats were measured once every week.On day75,after fasted for 14¹6h with free access to water,Oral glucose tolerance test?OGTT?were run,the blood glucose in rats were measured by Roche's blood glucose meter.After the test of OGTT,the blood samples were collected and the rats were sacrificed,the pancreas and liver of each rat were removed.The serum levels of Alanine transaminase?ALT?,Aspartate transaminase?AST?,Blood urea nitrogen?BUN?and Creatinine?CREA?,total cholesterol?TC?,triglyceride?TG?,Low density lipoprotein cholesterol?LDLC?and High density lipoprotein cholesterol?HDLC?were determined by biochemical estimation.The blood level of Fasting insulin?FINS?,Resistin,Leptin?LEP?and Adiponectin?ADPN?were measured by enzyme-linked immunosorbent assay?ELISA?,and indexes as Homeostasis Model assessment?HOMA-IR?,Insulin sensitivity index?ISI?and Homeostasis islet beta cell index?HBCI?of each rat were calculated.The levels of Superoxide dismutase?SOD?and Malondialdehyde?MDA?in liver and Glutathione peroxidase?GSH-Px?in serum were measured by Microplate reader,the levels of Fatty acid?FFA?,Catalase?CAT?in serum were measured by ultraviolet spectrophotometry.The expression of Insulin receptor substrate 2?IRS2?,Phosphoinositide3-kinase p85?PI3K p85?,Protein kinase B 2?Akt2?,and Adenosine5‘-monophosphate?AMP?-activated protein kinase?AMPK?2?mRNA in liver were measured by Real time rolymerase chain reaction?RT-PCR?,the expression of IRS2,PI3K p85,p-Akt,Akt and AMPK in liver were analyzed by Western Blot?WB?.Histopathological changes of pancreases and livers evaluated by hematoxylin-eosin staining?HE?and then examined by the light microscopy.Results:Effects of QSG on general clinical symptoms of the type 2 diabetic rats by HFD and STZ,compared with control group,the diet status,drank water,and urine excretion of rats in model group was obvious increased,the bodyweight was significantly decreased?P<0.05?,it was typical symptoms of type 2 diabetes mellitus-"three more and one less".Compared with Model group,rats in QSG groups,the diet status,drank water,and urine excretion was obvious decreased,the bodyweight was significantly increased?P<0.05?,QSG had obvious effects on ameliorating the symptoms of type 2 diabetes mellitus-"three more and one less".Effects of QSG on blood glucose of the type 2 diabetic rats by HFD and STZ,compared with control group,the levels of FBG,FINS,HOMA-IR,OCTT and AUC in model group were significantly increased?P<0.05?,the counts of ISI,HBCI in model group were significantly decreased?P<0.05?;compared with model group,the levels of FBG,FINS,HOMA-IR,OCTT and AUC in QSG groups were significantly decreased?P<0.05?,the counts of ISI in QSG groups were significantly increased?P<0.05?,but the levels of HBCI in QSG groups was no significantly changed?P>0.05?.QSG has obvious actions of decreasing blood sugar and increasing insulin sensitivity.Effects of QSG on liver and renal function of the type 2 diabetic rats by HFD and STZ,compared with control group,the levels of AST,ALT,BUN and CREA in model group were significantly increased?P<0.05?;compared with model group,the levels of AST,ALT,BUN and CREA in QSG group were significantly decreased?P<0.05?.The results indicate that QSG can renal protective effects,and drug safety.Effects of QSG on lipids of the type 2 diabetic rats by HFD and STZ,compared with control group,the levels of TG,TC,LDLC,FFA,Resistin and LEP in model group were significantly increased?P<0.01?,the level of HDLC and ADPN in model group were significantly decreased?P<0.01?;compared with model group,the levels of TG,TC,LDLC,FFA,Resistin and LEP in QSG groups were significantly decreased?P<0.05?,the levels of HDLC in QSG groups were significantly increased?P<0.05?,but the levels of ADPN in QSG groups was no significantly changed?P>0.05?.QSG decreasing serum lipids,and regulate lipid metabolism.Effects of QSG on anti-oxidative stress actions of the type 2 diabetic rats by HFD and STZ,compared with control group,the levels of CAT,GSH-Px and SOD in model group were significantly decreased?P<0.01?,the level of MDA in model group were significantly increased?P<0.01?;compared with model group,the levels of CAT,GSH-Px and SOD in QSG groups were significantly increased?P<0.01?,the level of MDA in model group were significantly decreased?P<0.05?.QSG can improve the antioxidant capacity.Effects of QSG on mRNA and protein of the type 2 diabetic rats by HFD and STZ,compared with model group,the mRNA expression of IRS2,PI3K p85,Akt2 and AMPK?2 in QSG groups were significantly increased?P<0.01?.Compared with control group,the protein expression of IRS2,PI3K p85,p-Akt,Akt and AMPK?in model group were significantly decreased?P<0.01?;compared with model group,the protein expression of IRS2,PI3K p85,p-Akt,Akt and AMPK?in QSG groups were significantly increased?P<0.01?.QSG having good hypoglycemic and hypolipidemic,can regulate of PI3K/Akt signaling pathway.Effects of QSG on pancreatic and liver pathological of the type 2 diabetic rats by HFD and STZ,compared with control group,the pancreatic and liver pathological in model group had some injury;compared with model group,pancreatic and liver pathological injury in QSG groups were alleviated.Conclusions:These data suggest that QSG improve the body weight,FBG and IR of type2diabetic rats,and had good effect in hypoglycemic and improving liver and kidney function.The results indicate QSG has good effect to protect pancreas and liver injury;QSG can effectively hypolipidemic and improve plasma adipokines in type 2 diabetic rats,and has good effect of regulate lipid metabolism;it can also effectively relieve oxidative damage in type 2 diabetic rats,and ameliorate their anti-oxidant capability and reduce oxidant's injure to their organism;QSG can improve IR maybe increased mRNA expression of IRS2,PI3K p85,Akt2,AMPK?2,and enhance IRS2,PI3K p85,p-Akt,Akt,AMPK?anailzed with protein expression.Therefore,it can be summarized that one of the mechanisms of treating diabetes with regulates glucose and lipid metabolism.QSG is a natural product and potential therapeutic agent with which to treat type 2 diabetes mellitus.