Effect of Midkine on Myocardial collagen metabolism in Rats with Myocardial Infarction

Objective To investigate effect of Midkine on Myocardial collagen metabolism in rats with myocardial infarction(AMI).Methods Fourty Wistar rats were randomly divided into four groups,n=10:Control group(control group),sham-operated group(Sham group),infarct model group(MI group),MK treatment group(MI+MK group).Rat models with myocardial infarction were established by the ligation of left anterior descending coronary artery,MI+MK group given the injection of MK immediately after myocardial infarction(1μg/rat,injection divided into five points).Four weeks later,remaining rats in each group were test serum MMP-9,PⅢNP level;take heart weighing,calculate the whole heart hypertrophy index;Will myocardial along the shape and slice,then Masson staining,determination infarcted thickness,length,infarction area,infarcted and non infarcted collagen volume fraction(CVF) of each group rats.Results Serum of MMP-9,PⅢNP level obviously increased in the MI group than in Control and Sham groups(P0.05);serum of MMP-9 level in the MI+MK group decreased obviously than in the MI group(P0.05),serum of PⅢNP level obviously increased than in the MI group(P0.05);infarcted thickness obvious thickened,length shortens significantly,infarction area decreased significantly in the MI+MK group than in the MI group(P0.05);infarcted collagen volume fraction of MI+MK group increased significantly than in the MI group(P0.05),and noninfarcted collagen volume fraction of MI+MK group significant decrease than in the MI group(P0.05).Conclusion MK can effectively relieve myocardial fibrosis degree,and its mechanism is by adjusting the collagen metabolism of infarction and noninfarction area in myocardial to fulfill.