内毒素血症时大鼠脂多糖结合蛋白的变化及其意义

Changes of Lipopolysaccharide-Binding Protein and Its Significance During Endotoxemia

目的 探讨内毒素血症时大鼠肝组织中脂多糖结合蛋白mRNA的表达、血浆中脂多糖结合蛋白 (LBP)含量的变化及其意义。方法 经大鼠尾静脉注入内毒素 (5mg/kg)建立内毒素血症动物模型 ,检测不同时点模型鼠肝组织中LBPmRNA的表达 ,同时检测血浆中LBP、内毒素、TNF α及IL 6含量的变化 ,并与对照组相比较。另取肝组织在电镜下观察其病理学改变。结果 随着内毒素血症时间的延长 ,内毒素组大鼠肝组织LBPmRNA的表达明显增强 ,血浆中LBP、TNF α和IL 6含量也明显增加 ,与对照组比较差异有高度显著性 (P<0 .0 1)。电镜观察见肝细胞脂肪变 ,线粒体空化 ,枯否氏细胞数量增多、体积增大、吞噬功能增强。结论 内毒素血症时 ,大鼠肝组织中LBPmRNA表达明显增强 ,血浆中LBP含量也明显增加。由此提示 ,增高的LBP可能在脂多糖介导的枯否氏细胞激活及产生、释放各种炎性介质中可能起了重要作用。

Objective To investigate changes of lipopolysaccharide-binding protein (LBP) and its clinical significance in activation of Kupffer cells (KCs) during endotoxemia.Methods Wistar rat endotoxemia model was established by injection of a dose of LPS (5 mg/kg, Escherichia coli O111∶B4) via the tail vein of rats, then sacrificed 1, 3, 6 and 12 hour respectively. Hepatic tissue was collected to measure LBP mRNA expression by reverse transcritase-polymerase chain reaction (RT-PCR). The levels of plasma endotoxins, LBP, TNF-α and IL-6 were determined. The pathological changes of hepatic tissue were observed under electron microscope.Results When the levels of plasma LPS elevated, expression of LBP mRNA in hepatic tissue were stronger than that in control rats. The levels of plasma LBP, TNF-α and IL-6 were increased markedly also in rat with endotoxemia when compared with that in control groups ( P <0.01). KCs were seen to be enlarged in size, their surface projections were increased in number, and their cytoplasm was full of phagocytic vacuoles or electron dense phagosomes which indicated active phagocytosis.Conclusion LPS can markedly up-regulate LBP mRNA expression in hepatic tissue, the levels of plasma LBP also increased. LBP may be a critical factor of LPS which stimulates KCs to produce and release different proinflammary mediators.