| ObjectivesLong-term exposure to nicotine increases the risk of heart muscle damage and cardiac dysfunction.However,it remains unclear whether nicotine-induced heart damage and lesions can be prevented and treated through mitochondrial reactive oxygen species(ROS)pathways.The aim of this study was to observe the effects of mitochondria-targeted antioxidant MitoTEMPO and deacetylase activator resveratrol on nicotine-induced heart disease.To provide basic research data for the mitochondrial pathway treatment of abnormal myocardial lesions.MethodsSD rats were given 0.6 mg/kg nicotine for 28 days to make nicotine heart disease model.The treatment group was treated with mitochondrial antioxidant MitoTEMPO,the resveratrol group was used as positive control,and the normal rats were given placebo as negative control for consecutive 28 days.Left ventricular systolic blood pressure and heart rate were measured.The heart tissues of rats were separated and collected,and the structure and parameters of the heart/myocardium were analyzed by morphological method.Mitochondrial ROS levels were measured by sulfur oxide fluorescence probe,antioxidant enzyme SOD2 activity was measured by glutathione(GSH)reduction,and the expression of 3-nitrotyrosine,a marker of oxidative stress,was detected by immunohistochemistry.Finally,the expressions of antioxidant genes(SIRT1,SIRT3,SOD2),hypertrophic genes(ANP,BNP),fibrosis genes(TGFβ1,Fn1)and inflammation-related genes(TNF-α,IL-6,ANXA1)were detected by molecular biological methods.The NOX2 subunit of NADPH oxidase was detected by SYBR Green PCR kit.ResultsNicotine administration resulted in increased heart weight,HW:TL and LV:TL ratios,increased expression of ROS and 3-nitrotyrosine in myocardial mitochondria,decreased glutathione ratio(GSH:GSSG),and decreased SOD activity(P<0.05),in conclusion,oxidative stress levels in the heart of rats increased.Analysis of HE and Sky Wolf scarlet staining revealed myocardial hypertrophy,fibrosis and inflammation.Gene expression analysis showed that NOX2,ANP and BNP were up-regulated by nicotine(P<0.05).Left ventricular fibrosis markers TGFβ1 and Fn1 gene expression were up-regulated(P<0.05).The expressions of pro-inflammatory cytokines TNF-α and IL-6 were significantly increased(P<0.05),the gene expression of anti-inflammatory molecule ANXA1 and its receptor FPR2 were significantly up-regulated(P<0.05).MitoTEMPO and resveratrol significantly reduced nicotine-induced increases in heart weight and HW:TL and LV:TL ratios.Decreased the mitochondrial ROS production induced by nicotine,normalized the GSH:GSSG ratio of rat myocardium,and decreased the expression levels of 3-nitrotyrosine and NOX2(P<0.05).Resveratrol significantly increased SOD activity and SIRT1 and SIRT3 expression in rat heart(P<0.05).It also decreased nicotine-induced cardiomyocyte hypertrophy and ANP and BNP gene expression(P<0.05).Resveratrol also reduced nicotine-induced up-regulation of TGFβ1,Fn1,TNFα,IL-6,ANXA1 and FPR2 expression(P<0.05).MitoTEMPO significantly reduced the expression of ANP gene in rats(P<0.05),inhibited nicotine-induced collagen deposition and up-regulated expression of TGFβ1 and IL-6(P<0.05).Conclusions1.After nicotine administration,the heart weight,the left ventricular weight,the ratio of heart weight to tibial length(HW:TL),the ratio of left ventricular weight to tibial length(LV:TL)and systolic blood pressure of SD rats were increased,and the levels of myocardial mitochondrial oxidative stress and inflammatory factors were increased,as well as cardiac remodeling and myocardial fibrosis.2.mitoTEMPO and resveratrol inhibited nicotine-induced mitochondrial oxidative stress and inflammation,and alleviated nicotine-induced cardiac remodeling and myocardial fibrosis in SD rat models.3.Resveratrol improved nicotine-induced mitochondrial oxidative stress,inflammatory response,cardiac remodeling and myocardial fibrosis significantly compared with mitoTEMPO. |
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