门静脉阻断及复流对小肠黏膜细胞凋亡及肝功能的影响

目的 探讨门静脉阻断不同时间对肝功能影响及复流后对小肠黏膜细胞损伤的变化.方法 健康成年日本大耳白兔24只,随机分为一个对照组A和二个实验组(以门静脉阻断30,45 min分别标为B、C组),每组8只.各实验组在术前1 h及按上述预定阻断的时间、解除阻断后30,60 min各取腔静脉血2 ml;对照组在相应时间段也各取腔静脉系统血1次.测定各血标本丙氨酸氨基转移酶(ALT)、门冬氨酸氨基转移酶(AST)的变化并予以比较分析.阻断后开放复流2 h,取　回肠肠段作连续切片,分别作HE染色和TUNEL、Bel-2、Bax免疫组化染色,观察其小肠黏膜损伤情况.细胞凋亡的变化以及Bcl-2、Bax表达.结果 A组在不同时间段ALT、AsT测定结果 均无显著性差异,对照组与之在相同时间段该二项指标的比较,B组阻断30 min时无显著性差异,而在复流后明显升高;C组阻断45 min时已明显升高,复流后再升高.实验组Bcl-2表达下调,Bax表达增加,凋亡指数上升.结论 门静脉阻断时间以30 min较安全.但复流有再灌注损伤;其对小肠黏膜细胞损伤表现以凋亡为主,且凋亡指数随阻断时间增加而上升.

Effect of portal vein occlusion and following restoration of portal vein flow on apoptosis of intestinal mucusal cells and liver function

Objective To investigate the effect of liver function with portal vein occlusion (PVO) in various phases and the following restoration portal vein flow on intestinal mucosal cells. Methods Twenty-four healthy adults white Japanese rabbits were randomized into 1 control group and 2 experimental groups (according to portal vein clamping for 30 min and 45 min). Each experimental group's blood samples were collected from caval vein 1 h before operation, by the end of portal vein oc-cluded, 30 min, 60 rain after relief of portal vein blocking, then with restoration of portal vein flow for 2 h and rabbit guts were continuously cut to sections for HE, TUNEL staining and Bcl-2, Bax protein immunohistochemical staining to observe the injury of intestinal mucosa cell apoptosis and the relation-ship between the expressions of Bcl-2 and Bax. The levels of blood glutamate-pyruvate transaminase (ALT), glutamic oxalacetic transaminase (AST) were measured and compared. Results The levels of ALT, AST in the control group did not significantly change. Compared with control group, group B did not change significantly with PVO 30 rnin in liver enzyme and they were significantly increased after portal vein occlusion relief. The levels of ALT and AST were increased obviously at 45 min with PVO, then raised again. Down-regulation of Bcl-2 expression, up-regulation of Bax expression and the increased index of apoptotic cell were found in each experimental group. Conclusion It may be more safe with PVO for 30 min. But the following restoration portal vein flow will bring about ischemia-reperfusion injury that is mainly apoptosis in the small intestine. The index of apoptosis will be raised with time prolongation of PVO.