Ablation of aldehyde reductase aggravates carbon tetrachloride-induced acute hepatic injury involving oxidative stress and endoplasmic reticulum stress.

Aldehyde reductase (Akr1a) has been reported to be involved in the biosynthesis of ascorbic acid (AsA) in the mouse liver. Because Akr1a is expressed at high levels in the liver, we aimed to investigate the role of Akr1a in liver homeostasis by employing a carbon tetrachloride (CCl4)-induced hepatotoxicity model. Akr1a-deficient (Akr1a(-/-)) and wild-type (WT) mice were injected intraperitoneally with CCl4 and the extent of hepatic injury in the acute phase was assessed. Liver damage was heavier in the Akr1a(-/-) mice than in the WT mice. Furthermore, severe hepatic steatosis was observed in the livers of Akr1a(-/-) mice compared to WT mice and was restored to the levels in WT mice by AsA supplementation. Since the presence or absence of AsA had no effect on the decrease in CYP2E1 activity after the CCl4 treatment, it appears that AsA plays a role in the process after the bioactivation of CCl4. Biomarkers for oxidative stress and ER stress were markedly increased in the livers of Akr1a(-/-) mice and were effectively suppressed by AsA supplementation. Based on these collective results, we conclude that Akr1a exerts a protective effect against CCl4-induced hepatic steatosis by replenishing AsA via its antioxidative properties.