Intervention Effect And Mechanism Of Dxxk On Level Of Serum LDL-C In APOE^-/-+HFD Mice

Objective:The purpose of this study is to establish an animal model with hyperlipidemia and high PCSK9 level for the study of the intervention effect and mechanism of Diaoxinxuekang on abnormal lipid metabolism,providing the evidence for clinical application of DXXK in treatment of hyperlipidemiaand cardiovascular disease.Methods:?1?Establish of animal model with hyperlipidemia+high PCSK9 level:APOE^-/-mice were fed with standard diet or high fat diet?standard diet+0.25%Cholesterol+20%milk fat?,respectively.Wild type C57BL/6J mice were fed with standard diet as negative control.The growth status of mice was observed.Serum TC,TG and LDL-C were detected by general enzyme method at 18 weeks,and serum PCSK9levels were detected by ELISA.The liver and abdominal aorta were collected,the formation of atherosclerotic plaque and liver lipid accumulation were observed by oil red O staining;?2?Effect of DXXK on lipid metabolism and the expression of PCSK9 in APOE^-/-+HFD mice:The mouse model of hyperlipidemia+high PCSK9 level was induced by APOE^-/-+HFD,and high,medium,low dose groups were gavaged with160,80,40 mg/kg DXXK,respectively.The positive control mice were gavaged with 10mg/kg Atorvastatin.The weight,diet and drinking water of each group were measured every week,and continuous administration for 18 weeks.Serum TC,TG,HDL-C,LDL-C and PCSK9 in each group were detected.In addition,Liver and abdominal aorta were collected,and hepatic lipid accumulation and atherosclerotic plaque formation were detected by oil red O staining;?3?Study on the mechanism of DXXK intervention of abnormal lipid metabolism in APOE^-/-+HFD mice:The expression of PCSK9 and LDLR mRNA in liver tissue was detected by qRealtime-PCR,and the expression of LDLR protein in liver tissue was detected by Western Blot.Results:?1?Study on animal model of hyperlipidemia+high PCSK9 level:?1?As compared with the control group,the same week old APOE^-/-mice serum TC,TG,LDL-C levels were significantly increased?P<0.01?,no significant difference in the level of PCSK9.?2?Compared with APOE-/-+ND group,APOE-/-+HFD group of mice serum PCSK9 levels were significantly increased in 18 weeks?P<0.01?.?3?In 18 weeks,There was a lot of lipid accumulation in liver of APOE^-/-mice,especially in APOE^-/-+HFD group.In addition,APOE^-/-+ND group of mice began to appear atherosclerotic plaque,and APOE^-/-+HFD group of mice showed significant atherosclerotic plaque.?2?Effect of DXXK on lipid metabolism and PCSK9 levels in APOE^-/-+HFD mice:?1?Compared with model group,there is no significant effect on body weight in mice,drinking water,and diet in administered 18 weeks of DXXK,but each dose group of DXXK could significantly decrease the serum TC,TG,LDL-C levels in APOE^-/-+HFD mice?P<0.01,P<0.05?;?2?DXXK each dose group could significantly decrease the serum PCSK9 level?P<0.01?,improve the formation of atherosclerotic plaque in APOE^-/-+HFD mice.?3?Study on the mechanism of DXXK intervention of abnormal lipid metabolism in APOE^-/-+HFD mice:Compared with the model group,DXXK?160,80,40 mg/kg?can significantly reduce the expression of PCSK9 mRNA in liver tissue in APOE^-/-mice?P<0.01?,and increase the expression of LDLR protein in liver tissue?P<0.01,P<0.05?,but it had no effect on the expression of LDLR mRNA.Conclusion:DXXK can significantly reduce serum TC,TG,LDL-C level,increased HDL-C level,and improve the formation of atherosclerosis in APOE^-/-mice,the mechanism of the decrease of serum LDL-C may be related to the inhibition of the expression of PCSK9 mRNA and its secretion into the circulation,so as to prevent the degradation of LDL receptor in liver tissue.