Chen H W, Hsu C, Lue S I, Yang R C
Department of Early Childhood Education and Nursery, Chia Nan College of Pharmacy and Science, Tainan, Taiwan, ROC.
Cell Stress Chaperones. 2000 Jul;5(3):188-95. doi: 10.1379/1466-1268(2000)005<0188:aosiab>2.0.co;2.
Apoptosis is a process by which cells undergo a form of non-necrotic cellular suicide. Although it is a programmed process, apoptosis can be induced by various stressors. During sepsis, apoptosis has been regarded as an important cause of cell death in the immune system, leading to unresponsiveness to treatment. This study was designed to investigate how prior heat shock induction can influence the rate of apoptosis in animals that have experienced sepsis. Sprague-Dawley rats were used, and experimental sepsis was induced by cecal ligation and puncture (CLP). Animals in the heated group were anesthetized and received heat shock by whole-body hyperthermia. They were sacrificed 9 h and 18 h after CLP as early and late sepsis, respectively. Apoptosis was evaluated by "DNA ladder" detection in agarose electrophoresis and Tdt-mediated dUTP nick end-labeling (TUNEL) assay. Hsp72 was detected by Western blot analysis. The results showed that the DNA ladder was detected most clearly in the thymus at the late phase of sepsis with time course dependence, while it showed less clearly in heat shock treated animals. Histopathological study by TUNEL assay obtained similar results in the thymus, where the cortex was more susceptible to apoptosis than the medulla. The Western blot analysis showed that the heat shock induced Hsp72 concomitant with an increase in Bcl-2:Bax ratio. In conclusion, heat shock pretreatment prevents rats from sepsis-induced apoptosis that may account for the better outcome of experimental sepsis. An increase in the Bcl-2:Bax ratio may in part explain the molecular mechanism of the effect of heat shock pretreatment.
细胞凋亡是细胞经历一种非坏死性细胞自杀的过程。尽管它是一个程序性过程，但细胞凋亡可由各种应激源诱导。在脓毒症期间，细胞凋亡被认为是免疫系统中细胞死亡的一个重要原因，导致对治疗无反应。本研究旨在探讨预先的热休克诱导如何影响经历脓毒症的动物的细胞凋亡率。使用了Sprague-Dawley大鼠，通过盲肠结扎和穿刺（CLP）诱导实验性脓毒症。加热组的动物被麻醉并通过全身热疗接受热休克。分别在CLP后9小时和18小时作为早期和晚期脓毒症处死动物。通过琼脂糖电泳中的“DNA梯带”检测和末端脱氧核苷酸转移酶介导的dUTP缺口末端标记（TUNEL）分析评估细胞凋亡。通过蛋白质印迹分析检测Hsp72。结果表明，在脓毒症晚期的胸腺中最清楚地检测到DNA梯带，具有时间依赖性，而在热休克处理的动物中则不太清楚。TUNEL分析的组织病理学研究在胸腺中获得了类似的结果，其中皮质比髓质更容易发生细胞凋亡。蛋白质印迹分析表明，热休克诱导Hsp72伴随Bcl-2:Bax比值增加。总之，热休克预处理可防止大鼠发生脓毒症诱导的细胞凋亡，这可能是实验性脓毒症预后较好的原因。Bcl-2:Bax比值的增加可能部分解释了热休克预处理作用的分子机制。
