Oxidative stress and metallothionein expression in the liver of rats with severe thermal injury.

The aim of this work was to study oxidative stress and the compensating mechanisms implicated in severe thermal injury using the burned rat model. Results showed that after thermal injury glutathione (GSH) level was decreased, oxidized glutathione (GSSG) and the ratio of GSSG/GSH increased both at 24 and 48 h in the liver. The activities of GSH-reductase (GSH-Rx) in the liver and GSH-peroxidase (GSH-Px) both in the liver and erythrocytes increased at 24 h and then decreased at 48 h. The level of alpha-tocopherol in plasma was reduced at 24 h. Lipid peroxide levels increased both at 24 and 48 h in the liver. The serum zinc level decreased, reaching a minimum at 12h, whereas liver zinc level was elevated and reached the maximum at 12 h. After severe thermal injury enhancement of metallothionein (MT) expression has been discovered for the first time. MT content in the liver increased both at 24 and 48 h. Expression of MT-I mRNA was activated at 3 h and reached the top at 24 h postburn. The conclusion is that severe thermal injury gives rise to oxidative stress and dramatic enhancement of MT expression could be one of the important compensative mechanisms of natural defense system postburn.