Midkine on ventricular remodeling and cardiac function in rats with acute myocardial infarction

Objective To study the effect of midkine(MK) on left ventricular(LV) remodeling and cardiac function in rats with acute myocardial infarction(AMI) . Methods Forty-five male Wistar rat models with AMI were established and randomized to either AMI control group,or MK treatment group,or sham-operated group(n=15 rats each) . Injection of 1 μg/200 g recombinant human MK was performed to each rat over the border zone myocardium at five sites after model establishment. Four weeks later,haemodynamic indexes and cardiac function indexes were detected,and so were the left ventricular weight(LVW) ,left ventricular mass index(LVMI) of heart preparation,myocardial infarct size,AngⅡ in plasma and cardiac muscle were measured. Results Compared with sham-operated rats,LVW,LVMI,left ventricular section and myocardial angiotensin Ⅱ level were significantly increased while the LV systolic pressure(LVSP) ,the maximum rising and dropping rates of LV pressure(±dp/dt) significantly decreased in AMI control group(all P0.01) . Compared with AMI control group,LVW,LVMI and left ventricular section in MK treatment group were significantly decreased(P0.05 or P0.01) ,besides,LVSP and ±dp/dt were significantly increased(P0.05) ,and myocardial infarct size and myocardial angiotensin Ⅱ level were significantly lower than AMI group. Conclusion Extrinsic MK is effective in attenuating left ventricular remodeling and protecting cardiac function.