肿瘤坏死因子-α及一氧化氮对暴发性肝衰竭肝损伤的作用

The roles of tumor necrosis factor αand nitric oxide on liver injury in fulminant hepatic failure

目的:研究肿瘤坏死因子α(tumor necrosis factor-α,TNF-α)及一氧化氮(nitric oxide,NO)在暴发性肝衰竭(fulminant hepatic failure,FHF)中对肝损伤的作用及相互关系。 方法:采用脂多糖(LPS)和D-氨基半乳糖(D-GaIN)构建FHF小鼠模型,采用ELISA方法和RT-PCR法检测血清TNF-α水平及肝组织TNF-αmRNA表达,采用硝酸还原酶法和RT-PCR法检测血清NO水平及肝组织iNOSmRNA,在小鼠用药后不同时期动态观察TNF-α、NO及肝损伤的变化,并对模型鼠分别给予TNF-α单抗和NO合成酶抑制剂L-NMMA,动态观察上述指标的变化。 结果:在FHF小鼠中,用药后2～4h肝组织TNF-αmRNA表达显著增加(0.91±0.75→0.82±0.08,P<0.01),伴血清TNF-α水平升高,给予TNF-α单抗后可阻断LPS/D-GalN介导的肝损伤,用药后4～8h肝组织iNOSmRNA表达及血清NO水平亦显著升高(0.87±0.08→0.85±0.08,P<0.01),给予L-NMMA后使肝损伤反而加重。FHF小鼠用药后8～12h血清总胆红素(TBiL)和ALT明显异常,肝组织切片可见肝组织大块状出血和坏死。 结论:在LPS/D-GalN所致的FHF中,TNF-α的产生与肝损伤成正相关,而NO在此模型中似有保肝和肝损伤的双重作用,TNF-α和NO在FHF模型鼠的肝损伤中起协同作用。

AIM:To study the roles of tumor necrosis factor-α(TNF-α) and nitric oxide(NO) on liver injury and the mural effect of the two factors in fulminant hepatic failure(FHF).METHODS: We established experimental model of FHF by LPS and D-GalN. Serumal NO level and iNOSmRNA expression in liver were studied by biochemistry method and RT-PCR method respectively, while serumal TNF-αlevel and TNF-α mRNA expression in liver were tested by ELISA method and RT-PCR method respectively. The change of TNF-α, NO and liver injury were observed in the different phase after drug administration. In addition, we observed the change of above items after pretreatment with anti-TNF-α IgG1 and NO synthase inhibitor L-NMMA respectively.RESULTS: In mice with FHF, TNF-α mRNA expression in liver increased statistically in 2 hours to 4 hours after administration of LPS and D-GalN, and the level of serumal TNF-α also increased(0.91±0.75→0.82±0.08,P<0.01). Pretreatment with anti-TNF-α IgGl inhibited the liver injury induced by UPS and D-GalN. iNOSmRNA expression in liver and serumal NO level also increased statistically in 4 hours and 8 hours after administration of LPS and D-GalN(0.91 ± 0.75→0. 82 ±0.08, P<0.01). Pretreatment with L-NMMA added to the liver injury. The level of serumal TBil and ALT were abnormal statistically in 8 hours and 12 hours after drug administration and there were massive bleeding and necrosis in the sections of liver.CONCLUSION: The produce of TNF-α was correlated with liver injury in experimental model of FHF induced by LPS arid D-GalN. while NO seemed to play not only protective and injurious roles. TNF-α and Noplayed coordinated action on liver injury in mice with FHF.