内毒素性肝衰竭大鼠TLR4mRNA表达、血清肿瘤坏死因子-α及肝细胞凋亡的动态变化

Kinetic changes of TLR4mRNA expression,TNF-α and hepatocytes apoptosis of D-galactosamine/lipopolysaccharide induced acute liver failure in rats

目的观察急性内毒素性肝衰竭大鼠肝组织中TLR4mRNA表达变化规律及其与血清肿瘤坏死因子-α水平、肝细胞凋亡的关系。方法雌性Wistar大鼠给予D-氨基半乳糖/脂多糖同时腹腔注射,计算动物死亡率及生存时间,动态观察给药后4、8、12h肝功能、血清肿瘤坏死因子-α、肝组织TLR4mRNA表达及病理变化,以TUNEL法检测原位细胞凋亡,计算凋亡指数。结果80%大鼠死于急性肝衰竭,平均生存时间15.6h±1.8h,病理表现为肝脏大块或亚大块坏死。给药后4、8、12h血清TNF-α增高含量及肝细胞凋亡均增加,血清TNF-α变化早于肝细胞凋亡指数的增加,肝组织TLR4mRNA的表达与血清TNF-α含量呈正相关(r=0.709,P=0.000)。结论内毒素通过单核吞噬系统TLR4介导TNF-α大量产生,激活炎症级联反应并诱导肝细胞凋亡是内毒素性肝衰竭的重要病理机制之一,阻断肝内外单核吞噬系统TLR4介导的的生理学作用,可能会对内毒素性肝衰竭起到一定防治作用。

Objective To describe the kinesis changes of TLR4mRNA expression,serum TNF-α and heaptocytes apoptosiss in lipopolysaccharide （ LPS）-induced acute liver failure. Methods Acute liver failure was established by intraperitoneal injections of D-galactosamine（400 mg/Kg）and lipopolysaccharide（ 100μg/kg） in female Wistar rats. Mortality and survival time were recorded in 10 rats. Ten rats were sacrificed at 4, 8, and 12 hours after treatment . Liver function test, serum TNF-α levels were measured, as well liver pathology studied. The apoptosis of liver cells was detected by TUNEL assay. Results Eighty percent rats died from acute liver failure after administration of D-galactosamine / lipopolysaccharide, with mean survival time of（ 15.6 ± 1.8 ）hours. Liver function tests were compatible with liver massive necrosis. Plasma level of TNF-α and liver cells apoptosis increased, with the change of TNF-α earlier. The expression of TLR4mRNA in liver tissue was positive correlation with concentration of plasma TNF-α（ r = 0. 709 ,P = 0. 000）. Conclusion The results show that TLR4 are involved in inducing the generous conduction of TNF-α,which activate inflammatory cascade reaction and initiate liver cell apoptosis. It suggests that TLR4 will be the novel strategy to prevent the development of lipopolysaccharide-induced acute liver failure.