Regulation Of Lipid Metabolism And Inflammatory Response By Sea Buckthorn Flavonoids To Inhibit Atherosclerosis And Its Mechanism

ObjectiveTo investigate the effects of sea buckthorn flavonoids on atherosclerosis from the perspectives of lipid metabolism,inflammatory response and regulation of intestinal flora,and to provide scientific basis and experimental foundation for the clinical treatment of atherosclerotic cardiovascular diseases with sea buckthorn flavonoids..MethodsNinety male Apo E^-/-mice were randomly divided into 6 groups of 15 mice each:control group（normal diet group）,model group（high cholesterol diet group,1.25%cholesterol）,saxifraga flavonoid low dose group（50 mg/kg）,medium dose group（100mg/kg）,high dose group（200 mg/kg）,and positive drug atorvastatin group（2.6 mg/kg）.The control group was given a normal diet,the remaining group was given a high cholesterol diet for 16 weeks,and the drug administration group was given the drug by gavage for 16 weeks.After 16 weeks of administration,the mice were executed by pentobarbital sodium anaesthesia.Atherosclerotic plaque lesions in the aorta were detected by Oil Red O staining;atherosclerotic lesions in the aortic sinus of mice were detected by HE and Oil Red O staining;the effects of sea buckthorn flavonoids on the expression of ABCA1,ABCG1,p-AMPKα,AMPK,SIRT1,LXRα,NLRP3,IL1-β,Caspase1,ASC proteins in aortic tissues were detected by protein immunoblotting.The effect of sea buckthorn flavonoids on the protein expression of ABCA1,ABCG1,LXRα,p-AMPKα,AMPK,SIRT1 in liver tissues was detected by protein immunoblotting.The effect of sea buckthorn flavonoids on intestinal flora was investigated by taking feces from mice for intestinal flora assay.Results1.weight,diet,blood lipid levelsThere was no significant difference in diet and weight compared to the blank group.At 0 weeks,there was no significant difference in TC,TG,LDL-C and HDL-C levels in all groups;at 8 weeks,compared to the control group,TC,TG and LDL-C were increased and HDL-C was decreased in the model group,TC was decreased in the sea buckthorn flavonoid medium dose group,LDL-C was decreased in the model group,and HDL-C was increased in the model group,At 16 weeks,TC,TG and LDL-C were increased and HDL-C was decreased in the model group,and compared with the model group,TC was decreased in the mid-dose,high-dose and positive drug groups,and HDL-C was decreased in the low,mid and high dose groups.TG was decreased,LDL-C was decreased in the sea buckthorn flavonoid high dose group,and HDL-C was increased in the sea buckthorn flavonoid high dose group and positive drug group.2.Aortic lesionsCompared with the control group,a large number of atherosclerotic plaques appeared in the inner wall of the aorta of the model mice;the atherosclerotic plaques were reduced in the low,medium and high dose groups of sea buckthorn flavonoid,with a certain quantitative-effect relationship.Compared with the control group,HE staining of the aortic sinus in the model group showed an increase in atherosclerotic plaque areas and narrowing of the arterial lumen,with more lipid and foam cells in the lesioned areas;compared with the model group,the arterial lumen narrowing improved in the low,medium and high dose groups of sea buckthorn flavonoid,with a small amount of lipid and foam cells in the lesioned plaque areas,with a quantitative effect relationship.Compared to the control group,oil red O staining of the aortic sinus showed that atherosclerotic plaques consisting of a large amount of structureless necrotic material and lipids were observed in the lumen of the aortic sinus in the model group;compared to the model group,the area of atherosclerotic plaque lesions in the lumen was reduced in the low,medium and high dose groups of sea buckthorn flavonoid,with a quantitative relationship.3.Aortic NLRP3 inflammatory vesicle protein and AMPK-SIRT1 protein expressionThe model group had increased protein expression of NLRP3,IL1-β,caspase1 and ASC（p<0.05 or p<0.01）and decreased protein expression of p-AMPKα,SIRT1 and LXRαin the aorta.The protein expression of NLRP3,IL1-β,caspase1 and ASC was decreased and the protein expression of p-AMPKα,SIRT1 and LXRαwas increased in the sea buckthorn flavonoid high dose group.4.Liver lesionsCompared to the control group,the liver of the model group became significantly whiter,larger,oilier and more brittle.Compared with the model group,the liver morphology of the Seabuckthorn flavonoid high dose group was reddish,less brittle and smaller in size.The liver index was significantly higher in the model group compared to the control group（p<0.001）.Compared with the model group,the liver index of mice in the sea buckthorn flavonoid high dose group was significantly lower（p<0.05）.HE staining of the livers in the model group showed significant liver lesions compared to the control group.The liver lesions were reduced in the sea buckthorn flavonoid high dose group compared to the model group.Masson staining of the liver showed an increase in collagen fibres in the model group compared to the control group.Collagen fibres were reduced in the sea buckthorn flavonoid high dose group compared to the model group.5.Hepatic AMPK,SIRT1,LXRα,ABCA1,ABCG1 protein expressionCompared with the control group,the protein expression of ABCA1,ABCG1,p-AMPKα,SIRT1,LXRαwas decreased in the model group（p<0.05 or p<0.01）.Compared with the model group,the protein expression was increased in the sea buckthorn flavonoid high dose group（p<0.05 or p<0.01）.6.Intestinal floraAlpha diversity analysis showed that compared to the control group,the Chao1index,Shannon index and Observed＿species were significantly lower,and the faecal flora diversity and community abundance were significantly lower in the model group.Compared with the model group,the Chao1 index,Shannon index and Observed＿species were significantly higher,and the faecal flora diversity and community abundance were significantly increased in the administered group,which was more obvious in the high dose of sea buckthorn flavonoids.Compared with the control group,the relative abundance of Firmicutes and Protebacteria increased in the model group,while the relative abundance of Bacteroidetes and Actinobacteria decreased in the model group,while the high dose of sea buckthorn flavonoid group showed the same trend as the control group.ConclusionSea buckthorn flavonoids are able to reduce atherosclerotic lesions and liver lesions.The mechanism may be related to the regulation of lipid metabolism,promotion of cholesterol efflux,inhibition of inflammation and regulation of intestinal flora.