内毒素休克小鼠一氧化氮与肝细胞凋亡的关系

目的探讨内毒素休克小鼠一氧化氮（nitric oxide，NO）与肝细胞凋亡的关系及其对肝功能的影响。方法36只小鼠随机分为对照组（r／,=6）和5个实验组（5个时间点，n=6）。实验组应用LPS腹腔注射建立小鼠内毒素休克模型，并分别于LPS给药后0．5h，2h，6h，12h，24h测定肝组织匀浆NO水平，并取肝细胞分离纯化，通过流式细胞仪观察各组肝细胞凋亡情况，同时采血分离血清测定各组小鼠血清丙氨酸转氨酶（ALT）和天冬氨酸转氨酶（AST）水平。结果肝组织匀浆NO水平从0．5h到6h逐渐升高，6h达高峰（P〈0．01），6h到24h逐渐下降至接近正常水平。流式细胞仪检测凋亡结果正常对照组凋亡率为2．33％，LPS五个时间组凋亡率平均分别为10．34％，21．65％，26．12％，30．12％，36．51％，LPS组肝细胞凋亡率明显高于对照组。血清AST和ALT水平在LPS注射2小时开始升高，并随时间延长逐渐升高。结论NO的大量产生早于肝细胞坏死和肝细胞凋亡，可能在内毒素休克早期诱导肝细胞凋亡和肝损伤。

The Realtionship of Nitric Oxide Level and Hypatocyte Apoptosis in Endotoxic Shock Mice

Objective To study the relationship of nitric oxide level and hepatocyte apoptosis in endotoxic shock mice and the effects on liver function.Methods 36 mice were randomly divided into normal control group(n6)and LPS group,which was composed of 5 subgroups(0.5,2,6,12,24 hour,n6).Endotoxic shock model was induced by administering LPS intraperitoneally(20 mg/kg).At different times after LPS injection,NO production in liver homogenate was detected by nitrate reductase chemical colorimetry.Hepatocytes apoptosis was determined by flow cytometry.Levels of serum alanine aminotransferase(ALT) and aspartate aminotransferase(AST) were measured using biochemical methods at the same time.Results The level of nitric oxide reached the peak at the 6~(th) hour and then gradually decreased.The rate of liver apoptosis in five LPS subgroups were respectively 10.34%,21.65%,26.12%,30.12% and 36.51% respectively,markedly higher than that of control group.The levels of AST and ALT of LPS group in serum begin to increase significantly (P<0.01) at 2 hours after LPS injection and progressively increase within the following 24 hours.Conclusions Spontaneous nitric oxide production is earlier than the liver injury and hepatocyte apoptosis,which are possibly induced by NO at the early stage of endotoxic shock.