Therapeutic Effect And Mechanism Of FTZ On Atherosclerosis In Diabetes Mellitus

Purpose:Atherosclerosis（AS）is one of the main vascular complications in patients with diabetes mellitus（DM）.The erosion or rupture of atherosclerotic plaque can lead to serious thrombotic events.Fufang Zhenzhu Tiaozhi capsule（FTZ）is a traditional Chinese medicine compound with good clinical effect on metabolic syndrome,which has been prescribed for more than 20 years.FTZ has been used to improve metabolic disorders such as hyperlipidemia,atherosclerosis,osteoporosis,and nonalcoholic fatty liver disease,but the exact mechanism remains unclear.The main purpose of this study was to explore the therapeutic effect and mechanism of FTZ on diabetic atherosclerosis.Methods:ApoE^-/-mice were randomly divided into two groups according to no difference in body weight,namely non-diabetic group and diabetic group.ApoE^-/-mice in non-diabetic group were given normal diet（ND）as control,while ApoE-/-mice in diabetic group were given high fat diet（HFD）.The diabetic mice were injected with streptozotocin（STZ,50mg/kg）for 5 consecutive days to induce diabetes.When the fasting blood glucose of the mice was≥11.1 mmol/L,the diabetic mice were considered to have successfully induced the diabetic mouse model.Then the diabetic mice were randomly divided into three groups:model group,FTZ group（1.2 g/kg）and positive drug group（Simvastatin（5 mg/kg）and metformin（100 mg/kg））.Measure body weight and fasting blood glucose once a week.After the experiment,all the mice were sacrificed.The serum levels of total cholesterol（TC）,triglyceride（TG）,low density lipoprotein cholesterol（LDL-C）and high density lipoprotein cholesterol（HDL-C）were determined by ELISA.The effects of FTZ on lipid deposition were analyzed by HE and oil red O staining,and the expression of SIRT3 in blood vessels was detected by immunohistochemistry.Human umbilical vein endothelial cells（HUVECs）were treated by hyperglycemia（HG,25m M）and oxidized low density lipoprotein（ox-LDL,100μg/m L）as diabetic atherosclerotic cell models and treated with FTZ（100μg/m L）.Protein or m RNA expression levels of SIRT3,Bax,Bcl-2,cleaved Caspase-3 were detected by RT-PCR and Western blot,and apoptosis levels were detected by TUNEL staining and Flow Cytometry.In addition,mitochondrial membrane potential was assessed by JC-1 staining.Results:Compared with ND group,lower body weight,higher fasting blood glucose,higher serum TC,TG,LDL-C level,and lower HDL-C level were observed in HFD group diabetic mice.After FTZ treatment,the blood glucose level,TC,TG,LDL-C level and HDL-C level of diabetic mice were significantly decreased,while the dyslipidemia level of diabetic mice was significantly improved.Blood vessel oil red O staining showed that the aortic intima plaque area decreased in diabetic mice after 12 weeks of FTZ treatment,while HE and oil red O staining showed that FTZ significantly improved lipid deposition in the aortic root.In addition,under the action of HG/OX-LDL,FTZ can enhance cell viability,improve endothelial cell apoptosis,up-regulate the expression of SIRT3,and increase mitochondrial membrane potential.However,inhibition of SIRT3expression by si RNA can attenuate the protective effect of FTZ on endothelial cells.These results suggest that FTZ may regulate SIRT3expression and improve endothelial cell apoptosis,thereby inhibiting HG/ox-LDL induced endothelial cell injury and effectively improving atherosclerosis in diabetic patients.Conclusion:FTZ can effectively reduce blood glucose and lipid levels and alleviate atherosclerosis in diabetic mice.The mechanism is related to inhibition of endothelial cell apoptosis by activating SIRT3expression.