Effect Of Helianthus Annuus L.on Atherosclerosis And Myocardial Infarction In ApoE^-/- Mice

Backgrond:Atherosclerosis（AS）is a chronic inflammatory disease which most often leads to myocardial infarction（MI）or stroke.The morbidity and mortality of cardiovascular and cerebrovascular diseases based on AS in China has been close to or even higher than that of many developed countries,and continues to rise.Therefore,the prevention and treatment of AS and MI will bring a series of health and economic effects.Objective:Helianthus Annuus L.（HAL）is composed of flavonoids and polysaccharides.Previous studies have shown that flavonoids have demonstrated beneficial effects on AS.The objective of this study was to investigate the effect on AS and MI and the related mechanism of HAL.In order to study the continuity of AS and MI,MI model was established in AS mice.Materials and methods:In part I study,high-fat diet（HFD）was used to induce apolipoprotein E-deficient(Apo E^-/-)mice to form AS models.The mice of control group were fed normal diet,while the mice of AS group were fed HFD and HAL group were fed HFD mixed with 5%HAL.After 24 weeks,samples were collected from eyeball blood,aorta,heart and fecal colon in mice under anesthesia.Pathological analysis of aortic plaque was conducted on mice,serum lipid indicators were detected,and then the oxidative stress indicators was measured,including malondialdehyde（MDA）,superoxide dismutase（SOD）,nitric oxide（NO）and glutathione peroxidase（GSH-Px）in the aorta were also measured.We also investigated the changes of gut microbiota composition by using 16S r RNA analysis.In order to analyze intestinal permeability,occludin and tight junction 1（ZO-1）levels in the colon were measured by immunohistochemistry.Then the concentrations of interleukin（IL）-1β,IL-6 and tumor necrosis factor-alpha（TNF-α）in the serum were assayed by ELISA,and expression levels of IL-1β,IL-6,TNF-αin the aorta were investigated via RT-q PCR.Finally,the expression changes of nuclear factorκB（NF-κB）and inducible nitric oxide synthase（iNOS）signaling pathways in aorta were determined by Western blotting.In partⅡandⅢstudy,Apo E^-/-mice were randomly divided into five groups.The mice of the control and MI groups were fed normal diet for 24-weeks,while the mice of AS and AS+MI groups were fed HFD,and the mice of AS+MI+HAL group were fed HFD containing 5%HAL.After 23 weeks,the coronary arteries ligation was performed on mice in the MI,AS+MI and AS+MI+HAL groups to form MI.One week later,the size and function of the left ventricle of the heart were examined by echocardiography in mice of five groups.Then,samples were collected from ophthalmic artery blood,aorta,heart in mice under anesthesia.Histopathological detection of the aortic plaque and infarcted myocardium were performed.The serum lipid inflammatory factors and heart failure indicators and the levels of oxidative factors in the aorta and heart tissue were detected.Results:1.With HAL treatment,the size of atherosclerotic lesion in HFD-induced AS model mice was reduced.HAL ameliorated dyslipidemia and decreased combined ratio.HAL up-regulated concentrations of SOD,NO and GSH-Px and down-regulated the levels of MDA in the aorta.In addition,16S r RNA analysis showed HAL also reduced diversity of the intestinal microbiota as well as the ratio of Firmicutes–to-Bacteroidetes ratio,while increased the relative abundance of probiotics,such as Akkermansia muciniphila and Lactobacillus.Then HAL decreased the permeability of intestine by increasing the levels of occludin and ZO-1 in the colon,consequently decreasd concentration of IL-6,IL-1βand TNF-αin serum and m RNA expressions in the aorta.In the end,HAL significantly decreased the expressions of NF-κB and iNOS in the aortic tissues of mice.2.AS model mice exhibited significant body weight gain,dyslipidemia and atherosclerotic lesions formation which were in accordance with the pathological changes of AS.The heart pathological of descending branch ligation in mice were in accordance with the pathological changes of MI.Furthermore,echocardiography and N-terminal pro brain natriuretic peptide（NT-pro BNP）revealed co-treatment with AS and MI led to deterioration of cardiac function.AS also aggravated inflammatory cell infiltration and myocardial fibrosis post-MI.The serum concentrations of inflammatory cytokines IL-6,IL-1βand TNF-αwere higher,and the levels of oxidative factors SOD and GSH-Px in heart tissue were more significantly decreased,while the levels of myeloperoxidase（MPO）and MDA were more significantly increased.3.HAL intervention ameliorated MI-induced cardiac morphological and functional changes,reduced myocardial inflammatory cell infiltration and fibrosis,and thus improved cardiac function.HAL also alleviated serum inflammatory response,and reduced serum IL-1β,IL-6 and TNF-αconcentrations,while HAL up-regulated SOD and GSH-Px levels,and down-regulated MDA and MPO levels in cardiac tissue.Conclusion:1.HAL alleviated AS through regulating dyslipidemia,restraining oxidative stress and inhibiting inflammation,while HAL reduced the inflammatory response of AS through regulating the intestinal microbiota,reducing intestinal permeability and inhibiting expression of NF-κB and iNOS increased by AS.2.It is feasible to establish MI model based on atherosclerosis model in mice.Cardiac remodeling inflammation and oxidative stress response were more obvious in mice of AS+MI model than MI model alone.3.HAL improved left ventricular remodeling after MI by inhibiting inflammation and oxidative stress response,reducing inflammatory cell infiltration and fibrosis in infarcted myocardium,thus improved heart function.Together,HAL alleviated AS plaque formation and left ventricular remodeling after MI by inhibiting inflammation and oxidative stress responses.