Abstract: Objective To investigate the expression of brain natriuretic peptide （BNP） in rat myocardial tissue after acute cardiac dysfunction and to explore the role of BNP in diagnosis of cardiac dysfunction in forensic practice. Methods Rat models of acute cardiac dysfunction were established. The expression of BNP protein and BNP mRNA in myocardial tissue after cardiac dysfunction were detected by immunohistochemistry, Western blotting and real-time RT-PCR. Results The extent of positive staining of BNP increased over the time course during cardiac dysfunction. The expression of BNP showed mild positive in cardiomyocytes from 1 h to 2 h. From 4 h to 6 h, the expression was moderate positive. From 10 h to 12 h, the BNP showed a strongest positive expression. The expression of BNP presented a significant raise with the increasing time of cardiac dysfunction by Western blotting and real-time RT-PCR. The expression of BNP mRNA increased significantly 1 h after cardiac dysfunction. Conclusion Investigating the expression of BNP protein and BNP mRNA in myocardial tissue may provide a new approach to evaluate the cardiac function for forensic pathologists.

Key words: forensic pathology, death, sudden, cardiac, natriuretic peptide, brain, rats