Ischemic preconditioning protects the mouse liver by inhibition of apoptosis through a caspase-dependent pathway
Ischemic preconditioning protects the mouse liver by inhibition of apoptosis through a caspase-dependent pathway
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DOI：
10.1002/hep.510300513
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发表时间：
1999-11-01
期刊：
影响因子：
13.5
通讯作者：
Clavien, PA
中科院分区：
文献类型：
--
作者：
Yadav, SS;Sindram, D;Clavien, PA
短暂的缺血和再灌注，称为缺血预处理，保护各种组织免受随后的持续缺血损伤。我们以前的研究表明肝细胞和肝窦内皮细胞的凋亡是缺血性肝损伤的一个重要机制。由于半胱天冬酶、钙蛋白酶和Bcl-2在细胞凋亡的调节中具有关键作用，我们假设缺血预处理通过下调半胱天冬酶和钙蛋白酶活性以及上调Bcl-2来抑制细胞凋亡。缺血10分钟，再灌注15分钟的预处理期最大限度地保护了长期缺血的肝脏。再灌注后，血清天冬氨酸转氨酶（AST）水平降低了3倍，在预处理的动物。缺血75分钟的所有动物均死亡，而接受缺血预处理的所有动物均存活。原位TUNEL法和DNA凝胶电泳法检测肝细胞和肝窦内皮细胞的凋亡，预处理显著减少。通过聚腺苷二磷酸核糖聚合酶（PARP）蛋白水解和特异性caspase-3荧光测定法测定的Caspase活性，被缺血预处理抑制。抗凋亡机制不涉及钙蛋白酶样活性或Bcl-2的表达，因为水平在控制和预处理的肝脏相似。总之，缺血预处理通过下调caspase 3活性抑制细胞凋亡，独立于钙蛋白酶样活性或Bcl-2表达，从而对长时间缺血提供显著保护。
A short period of ischemia and reperfusion, called ischemic preconditioning, protects various tissues against subsequent sustained ischemic insults. We previously showed that apoptosis of hepatocytes and sinusoidal endothelial cells is a critical mechanism of injury in the ischemic liver. Because caspases, calpains, and Bcl-2 have a pivotal role in the regulation of apoptosis, we hypothesized that ischemic preconditioning protects by inhibition of apoptosis through down-regulation of caspase and calpain activities and upregulation of Bcl-2. A preconditioning period of 10 minutes of ischemia followed by 15 minutes of reperfusion maximally protected livers subjected to prolonged ischemia. After reperfusion, serum aspartate transaminase (AST) levels were reduced up to 3-fold in preconditioned animals. All animals subjected to 75 minutes of ischemia died, whereas all those who received ischemic preconditioning survived. Apoptosis of hepatocytes and sinusoidal endothelial cells, assessed by in situ TUNEL assay and DNA fragmentation by gel electrophoresis, was dramatically reduced with preconditioning. Caspase activity, measured by poly (adenosine diphosphate ribose) polymerase (PARP) proteolysis and a specific caspase-3 fluorometric assay, was inhibited by ischemic preconditioning. The antiapoptotic mechanism did not involve calpain-like activity or Bcl-2 expression because levels were similar in control and preconditioned livers. In conclusion, ischemic preconditioning confers dramatic protection against prolonged ischemia via inhibition of apoptosis through down-regulation of caspase 3 activity, independent of calpain-like activity or Bcl-2 expression.