THE MECHANISM OF LIVER FAILURE AFTER EXCESSIVE HEPATECTOMY

大范围肝切除常导致致死性肝功能衰竭。其机制有两种学说：微循环障碍引起的间接损伤导致肝细胞坏死，细胞毒性障碍引起的直接损伤导致肝细胞凋亡。实验1采用我们首次建立的大鼠肝部分切除(PHX)模型对其机制进行了研究。大鼠用乙醚麻醉，分别进行90%和95%PHX。将大鼠分为两组：1组，90%PHX作为最大肝切除模型；2组，95%PHX，作为致死性肝衰竭模型。检测血清白介素1b、白介素6、肿瘤坏死因子α浓度，作为高细胞分裂素血症的指标。用苏木精-伊红(HE)染色观察残肝的组织学改变。用DAPI法和TUNEL法检测肝细胞凋亡率。Bc l-x蛋白(Bc l…的抗细胞凋亡成员结果：2组大鼠血清IL-1b、IL-6、TNF-α水平均高于1组，HE染色显示2组肝细胞变性较多，核分裂相较少，凋亡肝细胞较1组多，bclx蛋白表达较2组多。结论：细胞凋亡是肝过度切除后肝衰竭的重要因素之一。肝细胞周期受阻于p21、泛素和多种细胞周期蛋白的过度表达。Fas、多个caspase和细胞色素C的过度表达促进了肝细胞的凋亡。此外，95%PHX组肝损伤保护作用的热休克蛋白基因也有表达。实验1结果表明，作为抗凋亡因子或再生因子的Bclxl蛋白的表达有助于90%PHX后的存活。因此，我们用腺病毒载体将人bcl2基因(Hbcl2)导入DA大鼠肝脏。高效表达了hBCL-2。然后进行95%PHX。肝损伤得到改善，凋亡细胞数减少，但大鼠死亡。我们的结论是，hbc1-2基因转染部分阻止了细胞毒作用(细胞凋亡)，但不能确保存活。因此，在这些模型中，需要一些其他因素(例如，再生刺激器)来维持生命。较少

Massive hepatectomy often induced lethal hepatic failure. The mechanism has been described using two theories : indirect injury caused by microcircular disturbance induces necrosis to hepatocytes, and direct injury caused by cytotoxic disturbance induces apoptosis to hepatocyte.Exp.1We investigated the mechanism using our original experimental rat partial hepatectomy (PHx) models.Method : We use male Wistar rats. Rats were anesthetized with diethylether, performed 90%PHx and 95%PHx. The rats were divided into the following two groups : group 1, 90%PHx, as a maximum procedure of hepatectomy model, group 2, 95%PHx, as a lethal hepatic failure model. We investigated serum concentration of interleukin (IL)-1b, IL-6, tumor necrosing factor (TNF)-a, as a index of hypercytokinemia. Histological findings of remnant liver were also examined by hematoxylyn and eosin (HE) staining. Apoptotic hepatocytes were determined by using DAPI and TUNEL assay. Bcl-x protein (anti-apoptotic member of the Bcl … More -2 family) expression of remnant liver was studied by western blot analysis.Result : Serum concentrations of IL-1b, IL-6, TNF-a, were higher in group 2 than in group 1. HE staining showed that more degeneration hepatocytes and little mitosis appeared in group 2. Apoptotic hepatocytes were more in group 2 than in group 1. Bcl-x protein was expressed more in group 1 than in group 2.Conclusion : Apoptosis is one of the most important factors in the hepatic failure after excessive hepatectomy.Exp.2We applicated cDNA micoarray analysis in this models to clarify the mechanism of hepatic failure after excessive hepatectomy. The cell cycle of hepatocyte was stopped by overexpression of p21, ubiquitin and many cyclins. Apoptosis of hepatocyte was progressed by overexpression of Fas, many caspases and cytochrome C.Furthermore, genes of heat shock protein which protected from liver injury were rexpressed in 95%PHx group.Exp.3Results of Exp.1 demonstrate that expression of Bcl-xL protein as an anti-apoptotic factor or regeneration factor contributes to survival after 90%PHx. We therefore transfected human bcl-2 gene (hbcl-2) to DA rat livers by an adenovirus vector. The hbcl-2 was efficiently expressed. 95%PHx was then performed. Liver damage was improved and the apoptotic cell count decreased, but the rats died.We concluded that transfection of hbc1-2 gene partly prevents cytotoxity (apoptosis), but cannot ensure survival. Thus, some other factor is required (e.g, a regeneration stimulator) to maintain life in these models. Less