The Research Based On Ferroptosis To Explore The Mechanism Of Resveratrol On Myocardial Injury In Septic Rats

Objective:To investigate the mechanism of resveratrol on myocardial injury caused by sepsis-induced cardiomyopathy（SIC）based on ferroptosis.Methods:Rat SIC models were established by cecal ligation and puncture（CLP）surgery.Eighty SPF-grade male SD rats were divided into the following groups according to different treatments:Sham group,sepsis model（CLP）group,low,medium and high doses of resveratrol（L,M,H-RSV）group,iron death inhibitor（Fer-1）group and Sirt1 inhibitor（EX527）group.Twenty-four hours after modeling,the rats in each group were tested,and the degree of myocardial injury was observed by myocardial enzyme detection,cardiac dysfunction was observed by echocardiography,morphological changes of myocardial tissue were observed by HE pathological staining,the degree of mitochondrial injury was observed by cell experiment and transmission electron microscope,and ferroptosis-related proteins GPX4,ACSL-4,TFR,FTH-1 and key regulatory proteins Sirt1 and Nrf2 were detected by western blot.Immunohistochemical staining was used to observe the expression of regulatory protein Nrf2,the levels of Fe²⁺,MDA and GSH were measured by kit,and the changes of 4-HNE was observed by immunofluorescence staining to evaluate the degree of lipid oxidation.Results:（1）Compared with Sham group,myocardial enzymes in CLP group increased obviously,left ventricular ejection fraction decreased by echocardiography,myocardial cells swelled and inflammatory cells infiltrated by HE staining.After using resveratrol,it was found that it could improve the above parameters in a dose-dependent manner,and ferroptosis inhibitor also showed protective effect.（2）Transmission electron microscope showed that the mitochondrial membrane structure of rat cardiomyocytes was missing,and the mitochondrial cristae were blurred or even disappeared.High dose of resveratrol could reduce the mitochondrial damage.The experiment of H9C2 cardiomyocytes further showed that resveratrol could reduce ROS,decrease the mitochondrial membrane potential and alleviate the LPS-induced sepsis.（3）By observing the ferroptosis in rat myocardium,it can be found that compared with sepsis model group,the expressions of key proteins of ferroptosis in rat myocardium in high-dose resveratrol group are up-regulated,while the expressions of ACSL-4 and TFR are down-regulated,while the contents of Fe²⁺,GSH,MDA and 4-HNE are down-regulated,which indicates that high-dose resveratrol can alleviate ferroptosis.（4）The mechanism of resveratrol was further clarified by using Sirt1 inhibitor.It was found that Sirt1 could increase the expression of Nrf2,up-regulate the expression of ACSL-4 and TFR,down-regulate the expression of GPX4 and TFR,and increase the contents of Fe²⁺,GSH,MDA and 4-HNE in myocardial tissue of rats,which aggravated ferroptosis.Conclusion:It has been verified in the present study that resveratrol can regulate iron metabolism and lipid oxidation,reduce ROS production,alleviate mitochondrial damage,and inhibit ferroptosis by activating the Sirt1/Nrf2 signaling pathway,thereby improving SIC-induced cardiac dysfunction.