内毒素在肝脏缺血再灌注中的作用

The Role of Endotoxin During Hepatic Ischemia Reperfusion in Rats

目的 探讨内毒素在肝脏缺血再灌注损伤中的作用。方法 Wister大鼠随机分为 :内毒素组 ,肝脏缺血再灌注组 (HIR组 ) ,肝脏缺血再灌注复合内毒素血症组 (HIRE组 )。内毒素组自阴茎背静脉注射大肠杆菌内毒素 (LPS) 1 0mg/kg ;HIR组将肝左叶及肝中叶入肝血流阻断 60min后再灌注 ;HIRE组将肝左叶及肝中叶入肝血流阻断 60min后再灌注 ,同时自阴茎背静脉注射LPS1 0mg/kg。分别采用EMSA、免疫组化法及赖氏法检测再灌注后 1,3 ,12h肝脏组织中NF -κB结合活性、TNF -α的蛋白表达及血浆中ALT含量。结果 内毒素组NF -κB无明显激活 ,TNF -α无表达 ,血浆中ALT含量轻度升高 ;HIR组NF -κB活性仅于伤后 1、3h轻度增加 ,TNF -α有表达 ,ALT水平升高 ;与内毒素组及HIR组相比较 ,HIRE组损伤后NF -κB结合活性明显升高 ,至少可维持 12h ,同时肝组织TNF -α表达明显增加 ,血浆中ALT含量亦明显升高。结论 内毒素在HIR中可加重肝脏损伤 ,其机制可能是通过对NF -κB的双重激活引起肝内TNF -α等炎症相关细胞因子表达增加 ,从而加重肝脏损伤。

Objective To explore the role of endotoxin during hepatic ischemia reperfusion (HIR) in rats. Methods Wister rats were randomly divided into endotoxin, HIR and HIR plus endotoxin (HIRE) groups. In the HIR group, hepatic reperfusion was performed after 60 minutes of ischemia by interruption of the arterial and portal venous blood supply to the left lobes and middle lobes of the rat liver. In the HIRE group, LPS(1.0mg/kg) was injected via the dorsum vein of rat penis after ischemia and reperfusion. In the endotoxin group, LPS (1.0mg/kg) was injected via the dorsum vein of penis in the rats without ischemia and reperfusion. The NF-κB activities in the liver tissue of the rats were determined with EMSA. TNF-α expression levels in the liver tissue of the were measured with immunohistochemical staining. Serum ALT levels of the rats were also measured. Results NF-κB activity increased after reperfusion and remained high 12h after reperfusion in HIRE group compared with endotoxin group and HIR group. Both TNF-α expression levels and serum ALT levels increased markedly after reperfusion in HIRE group. Conclusion Endotoxin during HIR could induce hepatic injury. Endotoxin induced liver injury possibly by activating NF-κB followed by the subsequent expression of proinflammatory mediators in the liver tissue.