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目的 :探讨热应激对心肌细胞的损伤作用及其机制。方法 :用胰酶消化法分离Wistar大鼠乳鼠心肌细胞 ,使其暴露于 39℃、41℃和 43℃水浴进行热应激。用生物化学法测定培养液中乳酸脱氢酶 (LDH)活性的变化 ,用流式细胞仪 (FCM )测定心肌细胞凋亡率的变化 ,用台盼蓝 (trypanblue)染色法测定细胞坏死率的变化 ,用荧光分光光度法测定细胞内和培养液中活性氧 (ROS)含量的变化。结果 :39℃、41℃和 43℃热应激后 ,心肌细胞培养液中LDH的活性显著增高 ,心肌细胞的凋亡率由 4.74%分别增加到 5 .12 %、16 .31%和 2 8.97% ,坏死率分别由 3.5 2 %、3.5 5 %、3.5 3%增加到 3 .6 1%、5 .81%和 10 .8% ,应激后心肌细胞凋亡率随时间变化 ,6h时达最高峰 ,应激后细胞坏死率随时间延长逐渐降低。同时 ,应激后心肌细胞内和培养液中ROS含量明显增加。结论 :热应激可以引起心肌细胞损伤 ,细胞凋亡是热应激心肌细胞死亡的主要途径 ,热应激所致细胞ROS升高是导致细胞损伤的重要机制之一。
Objective: To investigate the effect of heat stress on cardiomyocyte injury and its mechanism. Methods: Cardiomyocytes of Wistar rats were isolated by trypsin digestion and exposed to 39 ℃, 41 ℃ and 43 ℃ water bath for heat stress. The changes of lactate dehydrogenase (LDH) activity in the culture fluid were measured by biochemical methods. The changes of apoptosis rate of cardiomyocytes were measured by flow cytometry (FCM). The cell necrosis rate was determined by trypanblue staining Changes, using fluorescence spectrophotometry determination of intracellular and culture fluid reactive oxygen species (ROS) content changes. Results: The LDH activity in cardiomyocytes was significantly increased after heat shock at 39 ℃, 41 ℃ and 43 ℃, and the apoptosis rate of cardiomyocytes increased from 4.74% to 5.12%, 16.31% and 2.897 respectively % And necrosis rate increased from 3.52%, 3.55% and 3.53% to 3.61%, 5.81% and10.8% respectively. The apoptosis rate of cardiomyocytes changed with time after stress, and reached the peak at 6h The peak, the cell necrosis rate gradually decreased with time after stress. At the same time, ROS levels in cardiomyocytes and in culture medium increased significantly after stress. CONCLUSION: Heat stress can induce cardiomyocyte injury. Apoptosis is the main pathway of heat-induced cardiomyocyte death. Increased ROS induced by heat stress is one of the important mechanisms leading to cell injury.