Changes in expression and production of heme oxygenase-1 in rats with acute liver injury induced by lipopolysaccharide

To investigate the changes of heme oxygenase-1 (HO-1) expression and production in rats with acute liver injury induced by lipopolysaccharide (LPS), and explore the role of HO-1 in the pathogenesis of liver injury. Liver injury was assessed histologically and the serum level of alanine transaminase (ALT) and aspartate transaminase (AST) were examined. The activity of super oxide dismutase (SOD) and the content of malondialdehyde (MDA) and carbon monoxide (CO) in liver tissues were also examined at the same time. HO-1 mRNA expression was examined at different time points following LPS treatment and the expression of HO-1 protein was determined by immunohistochemical staining. Administration of LPS caused severe hepatic damage, characterized by significant elevation of serum ALT and AST levels and hepatic MDA content as well as a remarkable reduction of liver SOD activity at 24 hr as compared with those in the control group. HO-1 activity was elevated significantly after modeling, showing a time-dependent manner from 6 to 24 hr, while expression of HO-1 protein was increased remarkably from 6 to 24 hr. Endogenous CO concentration in the liver of control rats remained very low but was elevated significantly after LPS treatment (6, 12, 24 hr), which was in accordance with the changes of HO-1. HO-1 activity and protein are increased significantly in rats with acute liver injury induced by LPS, suggesting that HO-1 plays an important role in the pathogenesis of acute hepatic damage.