IL-18在实验性暴发型肝衰竭发病机制中的作用

为探讨IL 18在暴发型肝衰竭发生中的表达变化及对其他细胞因子的调控作用。采用D 氨基半乳糖 (D Gal) 90 0mg/kg与脂多糖 (LPS ) 10 μg/kg诱导BALB/c小鼠暴发型肝衰竭 ,检测不同时间点血清转氨酶 (ALT、AST )和肝组织病理、DNA梯形条带 ,评估肝损伤情况 ;用半定量RT PCR和相应的分析软件分析不同时间点肝组织中IL 18mRNA、TNF αmRNA和IFN γmRNA表达及ELISA方法检测血浆IL 18、TNF α和IFN γ的蛋白表达。结果 :D Gal/LPS给予后 4h血清转氨酶明显升高 ,7h小鼠开始死亡 ,10h死亡率达 80 %。肝组织病理学检查发现 ,5h肝窦扩张、炎性细胞浸润、枯否细胞增生 ;7h肝细胞大量凋亡、坏死或肝组织出现大量出血性坏死 ;5h电镜示肝细胞核仁碎裂、线粒体肿胀或空泡变性 ;7h核仁边聚 ,呈半月型 ,表现为典型的凋亡形态学变化 ,线粒体大部分空泡变性。DNA电泳显示 5h始出现梯形条带。正常小鼠肝组织IL 18mRNA有少量表达 ,TNF αmRNA、IFN γmRNA微量表达。给药后 ,三者的mRNA分别在 1h、 2h、 3h达高峰 ,血浆中TNF α、IFN γ水平与其mRNA变化显著正相关 (rTNF α=0 4 3,P =0 0 1;rIFN γ=0 6 9,P <0 0 0 1) ,而血浆IL 18与其mRNA表达无明显相关 (r= 0 12 ,P =0 2 5 )。本实验诱导的暴发型肝衰竭模型中 ,肝细?

Role of IL-18 on the Pathogenesis of Fulminat Hepatic Failure

To explore the regulatory role of IL-18 on the LPS-induced fulminat hepatic failure and its expression alterations,a mouse model of fulminat hepatic failure was established by induction with D-galactosamine (D-Gal,900 mg/kg) and LPS (10 μg/kg). The serum transaminases (ALT and AST),the liver histopathology and the DNA ladders at the time points from 0 hour to 9 hours after intra-peritoneal injection with D-Gal/LPS were determined to evaluate the hepatic injury induced in the mouse model. The expression of mRNA of IL-18,TNF-α,IFN-γ and their corresponding proteins were measured by semi-quantitative RT-PCR and ELISA kit,and analyzed with the corresponding software. It was found that the serum transaminases and plasma TNF-α level were apparently elevated 4 hours after intrta-peritoneal injection of D-Gal/LPS. The treated mice began to die at 7 hours,and the mortality rate reached up to 80% at 10 hours. Obvious dilatation of hepatic sinuses,infiltration with inflammatory cells and proliferation of Kupffer cells could be demonstrated in the histopathological examinations at 5 hours with subsequent apoptosis and necrosis of the hepatic cells. At the late stage of pathological changes,more and more hepatocytes became necrotic. The DNA ladder was displayed after 5 hours of D-Gal/LPS injection by electrophoresis. The mRNA of IL-18,TNF-α and IFN-γ were expressed at lower lovel in normal mouse liver,while the expression of IL-18 mRNA was significantly elevated and maintained at higher level after intraperitoncal injection with D-Gal/LPS. Higher expressions of mRNA of TNF-α and IFN-γ could be also demonstrated following expression of IL-18 mRNA. Similar results could be obtained with proteins of TNF-α ( r TNF-α=0.43, P <0.01) and IFN-γ ( r IFN-γ=0.69, P <0.001) measured by ELISA. IL-18 mRNA was not positively correlated with the plasma IL-18. It concludes that apoptosis and necrosis exist in this mouse model,and the expressions of mRNA of IL-18,TNF-α and IFN-γ are increased in liver after intraperitoneal injection with D-Gal/LPS. The changes of transaminase and histopathology are later than that of the mRNA of IL-18 TNF-α and IFN-γ as well as their corresponding proteins. Furthermore,the expression of IL-18 mRNA prefers to mRNA of TNF-α and IFN-γ. It is suggested that IL-18,TNF-α and IFN-γ might be involved in this kind of hepatic injury.