烧伤并发内毒素血症早期肝损害与TNF—αmRNA表达的实验研究

目的 观察TNF－αmRNA及其蛋白的组织分布和细胞定位，探讨烧伤并发内毒素血症早期肝损害的发生机理。方法 选用20％Ⅲ度TBSA烧伤大鼠合并腹腔内毒素（LPS）注射造成烧伤复合内毒素血症肝损害模型，采用光镜，电镜及免疫组化原位杂交染色观察产肝脏的形态功能变化、血清TNF－α含量变化、肝组织TNF－α和TNF－α mRNA的细胞定位及其分布。结果 烧伤复合内毒素血症组，光镜下主要表现肝窦反应，枯否细胞（KCs)激活与增生以及肝细胞（HCs)变性坏死等；电镜下主要表现肝窦内血小板聚集、纤维素沉积与中性粒细胞（PMNs)扣押以及KCs、肝细胞退变溶解等。血清丙氨酸氨基转氨酶（ALT）显著升高（P＜0．01）和白蛋白（ALB）轻度下降。组织TNF－α主要定位于肝窦内皮细胞（SECs)、KCs。TNF－αmRNA主要定位于KCs、PMNs、巨噬细胞（MPs)。而在单因素组主要特点为病变程度轻，肝功能损害不明显，血清TNF－α峰值滞后以及组织TNF－α和TNF－αmRNA表达相对较弱等。结论 TNF－α是参与烧伤复合内毒素血症早期肝脏损害的重要细胞因子。

Experimental study on the early liver injury and expression of TNF-alpha mRNA after burns complicated by endotoxemia]

OBJECTIVE: To observe the distribution and cell localization of TNF-alpha mRNA and its protein and study their role on pathogenesis of liver injury in rats. METHODS: An animal model in which rats were subjected to 20% TBSA III degree burns combined with intraperitoneal injection of lipopolysaccharide (LPS) was used for this experiment. The changes in the hepatic morphology, functions and TNF-alpha content in the serum and the expression, localization of liver TNF-alpha and TNF-alpha mRNA were determined with LM and EM, quantitative analysis, immunohistochemistry(IHC) and in situ hybridization (ISH). RESULTS: It was showed that there were sinusoid reaction, KCs activation and degeneration, necrosis of HCs, and platelets aggregation, fibrin deposition and PMNs attachment in sinusoid. The activity of ALT was obviously elevated and the content of ALB was slightly lowered. The contents of TNF-alpha in serum showed the peak values at 3 h. TNF-alpha was mainly localized in sinusoid endothelial cells(SECs), Kupffer cells (KCs) and TNF-alpha mRNA was mainly distributed in KCs, polymorphonuclear neutrophils (PMNs) and macrophages(MPs). CONCLUSION: The results suggest that the expression and localization of TNF-alpha mRNA and its protein are in agreement with the pathological changes of liver injury. TNF-alpha is one of the key cytokines in pathogenesis of liver injury in rats after burns complicated by endotoxemia.