The Study Of Myocardial Inflammatory Cytokines Changes In Rats After Coronary Microembolization

Objective To evaluate the changes of myocardial inflammatory cytokines expression and the relationship with myocardial dysfunction in rats.after coronary microembolization.Methods 42μm microspheres were injected into the left ventricle during 10 seconds occlusion of the ascending aorta to make a rat model of coronary microembolization.Rats were randomly divided into sham group and coronary microembolization group(CME).Myocardial inflammatory cytokines expression and myocardial function were evaluated at 3hour,6hour,12hour,24hour,and 4week after coronary microembolization in each group.The effects of coronary microembolization on myocardial inflammatory reaction and heart function up to 4 weeks were studied.Myocardial inflammation was evaluated by accounting the number of infiltrated inflammatory cells in myocardium and analyzing the myocardial cytokines including tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β)and the anti-inflammatory cytokine interleukin-10(IL-10). Myocardial function was detected by echocardiography.Results The levels of TNF-α,IL-1β,IL-10 in CME group were markedly increased comparing to S group at 3hour,6hour,12hour and 24hour time points(P＜0.05),whose peak level appears at the 12hour time point but markedly,decreased at the 24hour time point.No differences had been found between these two groups at the 4week time point(P＞0.05).Echocardiography showed that theleft ventricular ejection fraction(EF)of CME group was markedly decreased comparing to S group at each time point.There was a significantly negative correlation between the expression of TNF-αmRNA, IL-1βmRNA and the EF at 3h,6h,12h,24h time point of CME group,but no correlation existed at the 4week time point.No microinfarction areas were found in S group.The everage area of the microinfarction in CME guoup was 8.31±3.86%.The inflammatory cells infiltration in CME group were markedly increased comparing to S group(P＜0.05).Conclusions The levels of TNF-α,IL-1β,IL-10 in myocardium are all markedly increased after coronary microembolization and the peak level appears at the 12h time point.The increase of TNF-α,II-1βplayed an important role on the myocardial dysfunction.