热缺血损伤对大鼠心脏死亡供肝线粒体形态和功能的影响

Impact of warm ischemia injury on mitochondrial morphology and function of rat donor liver after cardiac death

背景:如何才能很好的把握控制心脏死亡后捐献器官的功能活性,使移植物达到最佳功能状态是器官移植领域研究的重点方向之一。目的:初步探讨热缺血损伤对大鼠心脏死亡供肝功能的影响。方法:建立SD大鼠心脏死亡动物模型,将大鼠随机分为6组,分别为对照组(热缺血0 min组),热缺血10 min组,热缺血20 min组,热缺血30 min组,热缺血40 min组和热缺血50 min组。取各组大鼠肝脏标本制备超薄切片,透射电镜观察肝细胞结构改变并行Flameng评分。提取肝脏线粒体,用分光光度法测定细胞色素C氧化酶的活性。结果与结论:透射电镜下见热缺血30 min内肝细胞无明显改变,核膜尚完整,线粒体轻度肿胀,线粒体嵴未发生断裂,Flameng评分在2分以下。随着热缺血时间的延长,细胞核固缩,部分肝细胞自溶,可见凋亡小体,线粒体基质凝固,线粒体逐渐呈空泡状,Flameng评分3至4分。线粒体细胞色素C氧化酶活性在热缺血30 min内无明显改变,热缺血40 min组和热缺血50 min组发生明显降低。从线粒体形态和细胞色素C氧化酶活性两方面来看,热缺血时间在30 min内对肝脏功能影响较小,热缺血时间在40 min以上时肝脏呈不可逆性损伤。

BACKGROUND：How to control functional activity of donor liver after cardiac death and maintain the optimal function of grafts are the key issues in organ transplantation study. 〈br〉 OBJECTIVE：To preliminarily explore the effect of warm ischemia injury on the morphology and function of rat donor liver after cardiac death. 〈br〉 METHODS：Cardiac death model was established in Sprague-Dawley rats and the successful models were divided into six groups：control group （warm ischemia for 0 minute）, warm ischemia 10 group （warm ischemia for 10 minutes）, warm ischemia 20 group （warm ischemia for 20 minutes）, warm ischemia 30 group （warm ischemia for 30 minutes）, warm ischemia 40 group （warm ischemia for 40 minutes） and warm ischemia 50 group （warm ischemia for 50 minutes）. The rat liver specimens in each group were cut into ultrathin sections. The structure of liver cells was observed and photographed by electron microscopy. Flameng score was applied to analyze the degree of mitochondrial damage. Liver mitochondria were extracted and then spectrophotometry was used to assess the viability of cytochrome C oxidase. RESULTS AND CONCLUSION：Under electron microscopy, there were no significant changes in liver cells within 30 minutes of warm ischemia, nuclear membrane was intact, mitochondria mildly swel ed, no mitochondrial crista ruptured, and Flameng score was〈2 points. With the extension of warm ischemia time, the cells became swel ing, nuclear chromatin condensated, apoptotic body was clearly visible, mitochondrial matrix coagulated, mitochondria exhibited vacuolation, and Flameng score was 3-4 points. The viability of cytochrome C oxidase showed no significant difference within 30 minutes of warm ischemia, but began to significantly decrease at 40 and 50 minutes. The mitochondrial structure and function after liver injury is not obviously affected by 30 minutes of warm ischemia, and significant changes appear after 40 minutes.