早期急性心肌缺血所致的猝死常缺乏典型形态学改变，是法医鉴定的难点。课题组前期基于心肌组织形态学和心包液生化学研究发现CK-MB、cTn、BNP等指标能一定程度地反映生前心肌缺血程度，但由于死后变化等因素影响，在实际应用中仍存在一定局限性。研究表明，外泌体miRNA与心肌损伤密切相关，且miRNA具有组织特异性、耐受死后变化等特性，因此有望成为急性心肌缺血的法医学诊断标记物。本项目拟以急性心肌缺血动物模型为切入点，提取不同心肌缺血时间后心肌组织及血浆外泌体miRNA，通过二代测序和生物信息学分析，筛选差异性表达且与急性心肌缺血密切相关的miRNA，结合形态学、死后生化学检查，构建基于形态学、死后生化学、心肌及血浆外泌体miRNA多标记物检测的急性心肌缺血诊断体系及模式；再通过法医案例尸体心肌组织、血浆及心包液进行验证，探讨其在法医实践中的应用，为急性心肌缺血猝死的精准法医学鉴定提供客观依据。

Sudden death caused by early acute myocardial ischemic often lacks typical morphological changes and is difficult for forensic diagnosis. Based on our previous study of myocardial histomorphology and pericardial fluid biochemistry, we found that CK-MB, cTn, BNP and other indicators can reflect the degree of myocardial ischemia before death with a certain extent. However, due to factors such as postmortem changes, limitations in practical applications still exist. Previous studies have shown that exosomes miRNAs are closely related to myocardial injury, and miRNAs have tissue specificity and tolerance to postmortem changes. Therefore, they are expected to become ideal forensic diagnostic markers of acute myocardial ischemia. The present project intends to use the animal model of acute myocardial ischemia as the entry point. miRNAs will be extracted from myocardial tissue and plasma exosomes after different myocardial ischemic times. The second-generation sequencing and bioinformatics analysis will be performed to screen for the miRNA, which expressed differentially and related to early-stage acute myocardial ischemia. Combined with morphology and postmortem biochemical examination, we will construct an early acute myocardial ischemia diagnosis system and model based on multi-marker detection of morphology, postmortem chemistry, myocardial and plasma exosomes miRNAs; and then myocardial tissue, plasma and pericardial fluid of forensic case will be studied for further verification, and its application in forensic practice will be discussed to provide an objective basis for accurate forensic identification of sudden death caused by acute myocardial ischemia.