Experimental study of cardiocyte apoptosis in myocardial infarction of rabbits / 中华老年医学杂志

ABSTRACT

Objective To study the changes of the myocardial cell apoptosis in myocardial infarction of rabbits. Methods The model of rabbit with myocardial infarction was established.HE staining,TUNEL staining, immunohistro-chemistry staining, ultrathin section for electron microscope and DNA electronic gel phorensis were performed in samples of ischemia or infarction in different times.The position of apoptotic myocytes in different phases of ischemia were observed by light microscope and electronic microscope. Results After 30 minutes to 4 weeks ischemia.there were a few TUNEL positive nucleus of myocytes in the margin area of myocardial infarction;HE staining-found typical expressions of apoptosis,such as chromosome conglomeration,chromosome gathered at the edge or chromosome aggregation,dark-stained nucleus,cell shrinkage,were obvious in 4-8 hours.A lot of positive nucleus of myocytes stained by TUNEL were found in the early stages of myocardial ischemia in myocardial infarction.gradually ascended and then became hardly visible from 8 hours to 3 days.Nucleus swelling,karyorrhexis and karyolysis were found in the area of myocardial infarction.then cells were broken.DNA agarose electrophoresis found DNA fragment of most myocytes in 30 minutes of ischemia,just a few cardiocytes decomposed to the big segments.At 4hours of ischemia the most cardiocytes decomposed to big segments,and there were a blurry"ladder"in DNA strand breaks from 8 hours to 1 day.It showed that apoptotic cardiocytes existed in the margin area of myocadial infarction. Conclusions There are cardiocytes apoptosis in the margin area of infarction from 30 minutes to 4 weeks after myocardial ischemia.Maybe it relates to the reperfusion caused by collateralization establishment or infiltration from circumference.