Effect of acute skin thermal injury on subcutaneous glutathione, ascorbic acid and hydroxyl radical concentrations in anesthetized rats

Summary

The effect of acute thermal injury on subcutaneous oxidative stress, in anesthetized rats, was evaluated. A microdialysis probe was implanted in the subcutaneous tissue for continuous sampling of interstitial fluids, and the microdialysates were injected onto either an on-line or an off-line high performance liquid chromatography system. Hydroxyl radicals, glutathione, and ascorbic acid concentrations in the microdialysates were analyzed. Acute thermal injury was induced by skin contact of a hot (90°C) iron bar for 30 or 15 s. Subcutaneous hydroxyl radical production, represented as the increased formation of 2,3 and 2,5 dihydroxybenzoic acid (DHBA), did not increase significantly after thermal contact. Interestingly, both ascorbic acid and glutathione, two major physiological antioxidants, were significantly elevated in the subcutaneous interstitial fluids immediately after thermal contacts. The elevated subcutaneous glutathione levels rapidly decreased and returned to basal values 60 min after thermal contact. Ascorbic acid concentrations did not fully return to basal values even 3 h after thermal contact. The increase in ascorbic acid and glutathione may be responsible for scavenging of hydroxyl radicals that may form following thermal injury.