During passive heat stress, shifting of blood flow from the hepato-splanchnic to peripheral regions produces less favorable physiological conditions in the liver than in the skeletal muscle. We were wondering if the two organs differ in susceptibility to heat injury and thus examined the effects of heat shock exposure on apoptotic and heat stress-related markers in the gastrocnemius muscle and liver of mice. During heat exposure, mice had a peak core body temperature of 41.1 ± 0.7 °C. Heat-exposed mice showed higher levels of reactive oxygen species (ROS), cleaved caspases, fragmented DNA, and Drp1 protein expression in the gastrocnemius muscles than control mice. These changes were not observed in the livers of heat-exposed mice. Furthermore, the levels of glucocorticoid receptor, HSP70, and HSF1 proteins were significantly elevated in the gastrocnemius muscles of heat-exposed mice compared with that of control mice. The livers of heat-exposed mice also revealed increased expression of HSP70 but no changes in the other proteins. These results demonstrate that heat exposure induces significantly lower levels of the stress response and apoptosis in the liver than in the skeletal muscle of mice. The liver tissue resistance against heat stress is associated with low levels of heat-induced ROS production and mitochondrial fission protein expression.

在被动热应激期间，血流从肝内脏转移到外周区域，在肝脏中产生的生理条件不如在骨骼肌中产生的有利。我们想知道这两个器官对热损伤的敏感性是否不同，因此研究了热休克暴露对小鼠腓肠肌和肝脏中细胞凋亡和热应激相关标记物的影响。在热暴露期间，小鼠的峰值核心体温为 41.1 ± 0.7 °C。与对照组小鼠相比，热暴露小鼠腓肠肌中的活性氧 (ROS)、裂解的半胱天冬酶、DNA 片段和 Drp1 蛋白表达水平更高。在热暴露小鼠的肝脏中没有观察到这些变化。此外，与对照小鼠相比，热暴露小鼠腓肠肌中糖皮质激素受体、HSP70和HSF1蛋白的水平显着升高。热暴露小鼠的肝脏也显示 HSP70 表达增加，但其他蛋白质没有变化。这些结果表明，与小鼠骨骼肌相比，热暴露在肝脏中诱导的应激反应和细胞凋亡水平显着降低。肝组织对热应激的抵抗力与热诱导的ROS产生和线粒体裂变蛋白表达水平低有关。