Attenuation of disrupted hepatic active oxygen metabolism with the recovery of acute liver injury in rats intoxicated with carbon tetrachloride.

In this study, we examined how disrupted hepatic active oxygen metabolism at a progressed stage of carbon tetrachloride (CCl4)-induced acute liver injury is attenuated with the recovery of the injury in fed rats. When the progression and recovery of liver injury were assessed by measuring the activities of serum transaminases, indexes of liver cell damage, at 2, 24, 48, and 72 h after a single intraperitoneal injection of CCl4 (1.0 ml/kg body weight), an apparent liver injury was found at 2 h, the most progressed liver injury occurred at 24 h, and the progressed liver injury fairly recovered at 72 h. Hepatic superoxide dismutase and catalase activities decreased with the progression of liver injury but both decreases were maintained during the recovery of the injury. Hepatic glutathione peroxidase activity did not change with the progression and recovery of liver injury. Hepatic glutathione reductase activity decreased with the progression of liver injury and the decreased activity was returned up to the original level with the recovery of the injury. Hepatic glucose-6-phosphate dehydrogenase activity increased with the progression and recovery of liver injury but this increased activity was reduced at a late stage of the recovery. Hepatic reduced glutathione and ascorbic acid contents decreased with the progression of liver injury but both decreased contents were returned up to the original levels with the recovery of the injury. Hepatic vitamin E content decreased at an early stage of liver injury but this decreased vitamin E content increased over the original level with the progression of the injury and this increased vitamin E content was maintained during the recovery of the injury. Hepatic lipid peroxide content increased with the progression of liver injury and this increased content was returned near the original level with the recovery of the injury. These results indicate that in rats intoxicated once with CCl4, disrupted hepatic active oxygen metabolism at a progressed stage of liver injury is attenuated with the recovery of the injury mainly through the improvement of hepatic active oxygen metabolism mediated by the glutathione redox cycle and ascorbic acid.