Induction of stress protein in the liver upon brain death -changes in sinusoidal microcirculation of the liver and the tolerance acquisition to the ischemia/reperfusion injury

本研究建立了大鼠脑死亡模型。脑死亡诱导后2~3分钟脑电开始减少，脑死亡后1~3小时脑电完全平缓。角膜反射消失。血压随颅内压升高而急剧升高，而后迅速下降。此后持续稳定的低血压至少持续3小时。符合脑死亡的标准。在肝脏微循环方面，脑死亡模型中白细胞与肝窦内皮细胞的黏附增加，门静脉和肝窦后血管管径变小。白细胞流率明显降低。脑死亡患者外周血白细胞CD11表达明显增强。这些结果与脑死亡状态下由于α刺激阻断而维持肝脏微循环的推测是不一致的，这是从高度维持的…推测的。在犬脑死亡模型中，动脉血酮体比增加。然而，在移植后的血液再灌流时，从脑死亡状态的辅助物中获得的物资重新启动后，肝脏的能量代谢在冷保存过程中一度中断。因此，脑死亡时由于某些细胞因子的激活导致微循环的恶化，可能只会导致潜在的肝功能损害，即在肝脏储备功能范围内，而在冷缺血和再灌流后这种损害变得明显，从而导致原发性移植物功能障碍。至于脑死亡过程中热休克蛋白的产生，Western-Blot未检测到HSP72蛋白的表达，可能与脑死亡后3h的短暂时间有关。关于HSP72的m-RNA，即使是假手术动物也有表达。这就是为什么库欣现象触发HSP72表达的影响在本研究期间不能完全确定的原因。对脑死亡移植物维持的特殊微环境和脑死亡状态下细胞水平的应激反应的分析将使我们能够操纵脑死亡肝脏的应激反应，从而发展一种新的分子外科手术来改善肝移植。较少

Brain-dead model of rats was established in this research. Electro-encephalogram became reduced 2-3 minutes after induction of brain-death and it was completely flat at 1-3 hours during brain-dead state. Corneal reflex was disappeared. Blood pressure showed a steep elevation upon the increase of intracranial pressure and then rapidly decreased. Stable low blood pressure continued thereafter at least for 3 hours. The criteria of brain-death was fulfilled. Concerning the microcirculation of the liver, adhesion of leukocytes to sinusoidal endothelium was increased and the calibers of the portal vein and post-sinusoidal vessels were smaller in the brain-dead model. The flow rate of leukocytes was remarkably decreased. Expression of CD11 of leukocytes was significantly enhanced in the brain-death. These results were not consistent with the speculation of maintained hepatic microcirculation during brain-dead state due to alpha stimulation blockade, which was supposed from the highly maintain … More ed arterial ketone body ratio in the brain-dead model of dogs. However, the hepatic energy metabolism is once discontinued during cold preservation after procurement from brain-dead state aid is restarted upon blood reperfusion after transplantation. It is therefore possible that the deterioration of microcirculation due to activation of some cytokines during brain-death results only in the latent harm of the liver function, i. e. in the range of hepatic functional reserve, and the damage become overt after cold ischemia and reperfusion to produce primary graft dysfunction. As for production of heat shock proteins during brain-death, HSP72 protein was not detected by Western-blot, probably because of short period of 3 hours after the onset of brain-death. Concerning the m-RNA of HSP72, even the sham operated animal expressed it. This is why the effects of Cushing phenomenon to trigger the HSP72 expression could not be fully determined in this study period. The analyses of special microenvironment in which the brain-dead graft is maintained and those of the stress response at cellular level in the brain-dead state will enable us to manipulate the stress response in the brain-dead liver so that we can develop a new molecular surgery to improve liver transplantation. Less