实验性肝损伤大鼠肝脏HO-1的表达及CO水平变化

目的研究急性肝损伤时大鼠肝脏HO-1的表达情况和CO水平,探讨HO-1和内源性CO在大鼠急性肝损伤中的作用.方法制备急性四氯化碳肝损伤模型,采用RT-PCR和免疫组化法测定不同时间点大鼠肝脏HO-1 mRNA和蛋白的表达情况;测定各时间点肝组织SOD、MDA含量变化,同时测定股静脉血中HbCO水平和ALT、AST肝功能指标.结果HO-1mRNA在正常大鼠有弱表达,染毒3 h后表达显著增强,于24 h时间点表达最强,与对照组相比差异非常显著(P＜0.01);免疫组化结果显示;HO-1蛋白在正常大鼠表达较低或无,染毒3h后即有明显表达,16至48h的时间点内表达均显著增强,主要定位于肝实质细胞、库普细胞的胞浆内.对照组HbCO水平极低,给予四氯化碳3 h后HbCO水平开始升高,此后各时间点均明显高于对照组,差异有显著性,这与HO-1表达情况相一致.此外,染毒后大鼠血清ALT、AST和MDA明显升高,SOD活性则显著降低,和对照组相比差异均十分显著.结论大鼠急性肝损伤后出现HO-1表达持续上调和血中CO水平迅速增高,提示HO/CO系统参与急性肝损伤的病理生理过程,其表达增加可能对机体有重要调节作用.

Expression of heme oxygenase-1 and production of carbon monoxide in experimental liver injury models induced by carbon tetrachloride

Objective To investigate heme oxygenase-1 expression and carbon monoxide levels in acute liver injury induced by carbon tetrachloride(CCh) in order to explore the role of HO-I/CO system in the pathogenesis of liver injury. Methods A total of 35 male Wistar rats were allocated to establish acute liver injury models by carbon tetrachloride. Expression of HO-1 mRNA and protein at different time point was determined by RT-PCR and immunohistochemical methods. SOD activity and MDA concentration in the liver and HbCO levels in the blood were analyzed at the same time point. Serum aspartate aminotransferase(ALT) and alanine aminotransferase(AST) were also measured. Results HO-I mRNA expression was elevated significantly in rats 3 hours after CC1_4 injection, while HO-1 protein expression in liver sections were also obvious in comparison with control group.HO-1 protein was mainly observed in hepatocytes, Kutfer cells, et al. In the control group, HbCO levels were so low that it could not be measured sometimes. But when rats were injected with CC1_4, significant elevations of HbCO levels were found in the subsequent time point, which was parallel with HO-1 expression. Additionally, SOD activity decreased remarkably in the CC1_4 group while MDA concentration, ALT and AST rose higher in relation to severity of liver injury. Conclusion The results showed that HO-1 expression and CO production were higher in rats with liver injury in duced by carbon tetrachloride than those in control group. HO-l/CO system may play an important role and have protective effect in the development of liver injury.