Chen H B, Zhang X C, Cheng Y F, Abdelnasir A, Tang S, Kemper N, Hartung J, Bao E D
College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.
Institute for Animal Hygiene, Animal Welfare and Farm Animal Behaviour, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany.
Genet Mol Res. 2015 Mar 20;14(1):1994-2005. doi: 10.4238/2015.March.20.9.
To investigate the mechanism of sudden death as a result of stress-induced damage to heart tissue and myocardial cells and to investigate the cardioprotective role of Hsp70 during heat stress, the distribution and expression of Hsp70 was evaluated in the heart cells of heat-stressed rats in vivo and heat-stressed H9c2 cells in vitro. After exposure to heat stress at 42°C for different durations, we observed a significant induction of CK, CK-MB, and LDH as well as pathologic lesions characterized by acute degeneration, suggesting that cell damage occurs from the onset of heat stress. Immunocytochemistry showed that Hsp70 was distributed mainly in the cytoplasm of myocardial cells in vivo and in vitro. Hsp70-positive signals in the cytoplasm were more prominent in intact areas than in degenerated areas after 60 min of heat stress. Hsp70 protein levels in myocardial cells in vitro decreased from the beginning to the end of heat stress. Hsp70 protein levels in rat heart tissues in vivo decreased gradually with prolonged heat stress, with a slight increase at the beginning of heat stress. These results indicate that Hsp70 plays a role in the response of cardiac cells to heat stress and that decreased Hsp70 levels are associated with damage to rat myocardial cells in vitro and in vivo. Significant differences were found in hsp70 mRNA, which began to increase after 20 min of heat stress in vitro and after 40 min in vivo. This indicates that hysteresis is involved in mRNA expression after heat stress in vivo.
为了研究应激诱导的心脏组织和心肌细胞损伤导致猝死的机制，以及研究热应激期间热休克蛋白70（Hsp70）的心脏保护作用，我们评估了体内热应激大鼠心脏细胞和体外热应激H9c2细胞中Hsp70的分布和表达。在42°C暴露于热应激不同持续时间后，我们观察到肌酸激酶（CK）、肌酸激酶同工酶（CK-MB）和乳酸脱氢酶（LDH）显著升高，以及以急性变性为特征的病理损伤，这表明热应激开始时细胞就发生了损伤。免疫细胞化学显示，Hsp70在体内和体外主要分布在心肌细胞的细胞质中。热应激60分钟后，完整区域细胞质中的Hsp70阳性信号比变性区域更明显。体外心肌细胞中Hsp70蛋白水平在热应激开始到结束时逐渐降低。体内大鼠心脏组织中Hsp70蛋白水平随着热应激时间延长而逐渐降低，在热应激开始时略有升高。这些结果表明，Hsp70在心脏细胞对热应激的反应中起作用，并且Hsp70水平降低与体内外大鼠心肌细胞损伤有关。热休克蛋白70（hsp70）mRNA存在显著差异，体外热应激20分钟后和体内热应激40分钟后开始增加。这表明体内热应激后mRNA表达存在滞后现象。
