The Research Of Apelin-13 On Resisting Oxidative Stress And Improving Heart Function In Myocardial Ischemia-reperfusion Injury

Objective:Through the study of Apelin-13’s effects on the oxidative stress status and the influence of cardiac mechanical function in vitro rat cardiac myocardial ischemia-reperfusion(I/R) injury,to discuss if it can improve the oxidative stress,cardiac function in I/R injury,and its possible mechanism.Methods:98 male SD rats were selected for the research object,each rat weights 250 g to 350 g,eihgt anniversary,purchased from the university of south China animal experiment center,the research subjects were randomly divided into 7 groups(n=14).The control group were perfused 60 min with liquid oxygen filling of K-H.Blocking perfusion 30 min of the control group,and then use standard perfusion fluid streams 30 min as the I/R group.Before stopping perfusion,the hearts were treated with 100nmol/L Apelin for 10 min,and the Apelin was given continued during the next 30 min,as the I/R+AP group.Based on the I/R+AP group,5 umol/L chelerythrine(CHE) of PKC inhibitors joined in it as the I/R+AP+CHE group.50umol/L LY-294002(LY) of PI3 K inhibitors was joined in I/R+AP group as the I/R+AP+LY group.1umol/L εV1-2 of PKCε inhibitors was joined in I/R+AP group as the I/R+AP+εV1-2 group.100umol/L 5-hydroxydecanoate(5HD) of mitoKATPchannel inhibitors was joined in I/R+AP group as the I/R+AP+5HD group.Connecting the heart aorta with the heart perfusion plant(Langendorff),then reverse perfusion it.Using the I/R model of heart that reperfusion 30 min after global ischemia 30 min.At the same time,recording of the coronary blood flow,the left ventricular systolic pressure(LVSP),left ventricular pressure(LVDP) formation,left ventricular end-diastolic pressure(LVEDP) and ventricular rate(HR).Using different methods measure cardiac oxidative stress state.Fluorescent DCFH load determination single cardiomyocytes ROS content.Western blot analysis the oxidative modification level of SERCA and RyR.Microporous filter method to calculate the Ca2+ uptake by SERCA.Liquid scintillation counting method to detect 3h-ryanodine binging force.Using SPSS18.0 software for statistical analysis of the data.Results: In the process of I/R,Apelin-13 could reduce the LDH,LVEDP,and elevate LVSP,LVDP,HR.Further study found that Apelin-13 could improve redox state and reduce ROS level in the myocardial cells,lower the level of SERCA tyrosine nitration,elevated SERCA and RyR GSH level,restore the absorption of sarcoplasmic reticulun to Ca2+ mediated by SERCA,and increase the adhesion strength of the 3h-ryanodine with RyR to promote the releasing of Ca2+,thus stable the balance of Ca2+ in myocardial intracellular.After the pretreatment of PI3 K,PKC,PKCε, mitoKATP channel inhibitors,the role of Apelin-13 was weakened.Conclusion:Apelin-13 could reduce myocardial injury and improve the heart function after I/R.The mechanism may be that Apelin inhibiting the oxidative stress reaction,reducing the production of ROS in the myocardial after I/R injury,and then improve the adjustment ability of SERCA and RyR to myocardial intracellular Ca2+.The cardioprotection maybe mediated by PI3K-PKC(PKCε)-mito KATPchannel pathway.