中介素预处理对大鼠心肌细胞缺氧的保护作用

目的 通过对中介素（intermedin,IMD）预处理的大鼠心肌细胞缺氧后作用机制的研究,为法医病理学研究心脏性猝死机制提供思路. 方法 大鼠H9c2心肌培养细胞随机分为对照组、缺氧组和IMD预处理组.采用MTT比色法、透射电镜、激光共聚焦显微镜和流式细胞术检测各组心肌细胞存活率、细胞超微结构、细胞内游离钙离子浓度（Ca2＋]i）及细胞凋亡率.结果 与对照组比较,缺氧组细胞存活率明显降低（P＜0.05）,内部超微结构存在损伤,而IMD预处理显著提高细胞存活率（P＜0.05）、减轻缺氧对心肌细胞结构的损伤.缺氧组细胞Ca2＋]i（荧光强度）和细胞凋亡率较对照组升高（P＜0.05）,IMD预处理降低了缺氧对细胞Ca2＋]i（荧光强度）和凋亡率的影响（P＜0.05）. 结论 IMD能提高缺氧心肌细胞存活率、减轻缺氧引起的细胞内钙超载从而抑制细胞凋亡,可以揭示心肌细胞缺氧保护作用的机制,为心脏性猝死鉴定提供依据.

Protective Effects of Intermedin Preconditioning on Hypoxic Injury in Rat's Cardiac Myocytes

Objective To observe the effects of intermedindiac myocytes and to provide the hypothetical mechanismpreconditioning on hypoxic injury in rat＇s car-of sudden cardiac death in the field of foren-sic pathology. Methods The H9c2 cultured rat cardiac myocytes were randomly divided into controlgroup, hypoxia group and IMD group. The myocardial cell viability, cellular ultrastructure, intracellularcalcium concentration and apoptosis rate were determined by MTT assay, transmission electron mi-croscopy, laser scanning confocal microscope and flow cytometry, respectively. Results Compared withthe 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 ofcardiac myocytes （P〈0.05）. Compared with the control group, Ca2qi （fluorescence intensity） and apop-tosis rate significantly increased in the hypoxia group, but decreased in the IMD group （P〈0.05）. Con-clusion IMD increases the cell survival rate and decreases the cell apoptosis inhibited by intracellularcalcium overload from hypoxia. This finding may reveal the mechanism of protective effects of myocar-dial hypoxia, and provide a scientific basis for the identification sudden cardiac death.