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目的探讨模拟失重对大鼠门静脉内毒素水平和肝脏超微结构的影响及意义。方法成年雄性Wistar大鼠84只,体质量280～310 g,按随机区组设计,2个因素组为模拟失重组和对照组,每个因素组设7个时相组(n=6),包括6 h、12 h、1 d、2 d、3 d、5d、7 d。采用尾悬吊法建立模拟失重动物模型,应用动态浊度法鲎试验测定门静脉内毒素水平,透射电镜观察肝组织超微结构变化。结果实验组和正常对照组大鼠门静脉中均可检测到内毒素。与对照组比较,模拟失重6 h大鼠门静脉内毒素水平即明显增高(P<0.05),12 h形成高峰,随模拟失重时间延长,门静脉内毒素水平呈下降趋势,5 d组形成低谷,接近对照组水平,7 d组的门静脉内毒素水平又趋升高。透射电镜观察到模拟失重组肝细胞染色质浓缩边聚,线粒体肿胀,部分空泡变性,内质网扩张,出现凋亡小体。尾悬吊第1天、第2天最为明显。结论研究结果提示模拟失重导致门静脉内毒素血症和肝脏超微结构损失性改变。
Objective To investigate the effect of simulated weightlessness on portal venous endotoxin and liver ultrastructure in rats and its significance. Methods Eighty-four adult male Wistar rats weighing 280-310 g were randomly divided into two groups: simulated weightlessness group and control group. There were 7 phase groups (n = 6) for each factor group, Including 6 h, 12 h, 1 d, 2 d, 3 d, 5 d, 7 d. Animal models of simulated weightlessness were established by tail suspension method. The levels of portal vein endotoxin were measured by dynamic nephelometry and ultrastructural changes of liver tissues were observed by transmission electron microscopy. Results Endotoxins could be detected in the portal vein of experimental group and normal control group rats. Compared with the control group, the level of endotoxin in portal vein was significantly increased at 6 h after simulated weightlessness (P <0.05), and peaked at 12 h. The endotoxin level in portal vein decreased with the increase of simulated weightlessness, In the control group, the levels of portal venous endotoxin in 7 d group tended to increase. Transmission electron microscopy was observed in the simulated weightless group of hepatocyte chromatin condensation edge, mitochondria swelling, some vacuolar degeneration, endoplasmic reticulum dilatation, apoptotic bodies. Tail suspension on the first day, the first two days most obvious. Conclusions The results suggest that simulated weightlessness leads to portal venous endotoxemia and loss of liver ultrastructure loss.