Abstract: Objective To explore the expression of fibroblast activation protein α （FAPα） and transforming growth factor-β1 （TGF-β1） in myocardial cytoplasm for the cases of sudden death due to acute myocardial ischemia. Methods The heart tissues of 47 cases were collected. All cases were divided into three groups： control group, acute myocardial infarction group and recurrent myocardial infarction group. FAPα and TGF-β1 expressions were explored in myocardial cytoplasm by immunohistochemistry technology. The staining results were collected by image analysis system and then the positive area ratio and average optical density were detected. The positive signal differences were compared among the groups. Results Strong FAPα and TGF-β1 expressions were detected in myocardial cytoplasm in both acute and recurrent myocardial infarction groups. The expression of FAPα was not detected in myocardial cytoplasm in control group and TGF-β1 expression showed a weak positive result. FAPα and TGF-β1 expressions showed the statistical difference（P<0.05） in myocardial infarction （acute and recurrent） groups and control group. Conclusion FAPα and TGF-β1 can be the diagnostic markers for determing acute myocardial infarction.

Key words: forensic pathology, immunohistochemistry, myocardial ischemia, transforming growth factor-β1, fibroblast activation protein α