Abstract: Objective To observe the effects of intermedin preconditioning on hypoxic injury in rat’s cardiac myocytes and to provide the hypothetical mechanism of sudden cardiac death in the field of forensic pathology. Methods The H9c2 cultured rat cardiac myocytes were randomly divided into control group, hypoxia group and IMD group. The myocardial cell viability, cellular ultrastructure, intracellular calcium concentration and apoptosis rate were determined by MTT assay, transmission electron microscopy, laser scanning confocal microscope and flow cytometry, respectively. Results Compared with the control group, cell viability obviously decreased with inner ultrastructure injury in the hypoxia group （P<0.05）, while cell viability significantly increased in the IMD group by reducing the hypoxia injury of cardiac myocytes （P<0.05）. Compared with the control group, [Ca2+]i （fluorescence intensity） and apoptosis rate significantly increased in the hypoxia group, but decreased in the IMD group （P<0.05）. Conclusion IMD increases the cell survival rate and decreases the cell apoptosis inhibited by intracellular calcium overload from hypoxia. This finding may reveal the mechanism of protective effects of myocardial hypoxia, and provide a scientific basis for the identification sudden cardiac death.

Key words: forensic pathology, anoxia, myocytes, cardiac, intermedin, rats