Can superoxide dismutase prevent postburn dermal ischemia?

Decreasing progressive dermal ischemia after burning could theoretically limit the amount of skin necrosis. It is controversial whether the use of free radical scavengers could prevent the progressive dermal ischemia of the postburn stasis zone. We evaluated the effect of superoxide dismutase (SOD) on preventing postburn dermal ischemia in animal models by the India ink perfusion and skin transparent preparation techniques. The closely clipped backs of guinea-pigs were bathed in 75°C water for 10 s. Within 5 min postburn, SOD-treated groups were administered SOD (10 000 u/kg) intra-peritoneally every 6 h. All animals were perfused with 70 per cent India ink via cervical artery cannuala by 16 kPa constant pressure at 0, 8, 16, 24 h postburn, and the skin transparent preparations were made, while the level of malonyl dialdehyde (MDA) in skin tissue was assessed. The results showed that with prolongation of postburn time, the rate of filling of India ink in skin capillary plexuses decreased gradually (p<0.01). MDA increased continuously, which was related to postburn dermal ischemia (r = 0.689, p<0.01). Though the level of MDA decreased in SOD-treated groups, the India ink filling rates showed no significant difference between controls and experimental groups (p > 0.05). The results were also confirmed by observation of skin transparent preparations and TEM. This study suggests that superoxide dismutase fails to prevent progressive dermal ischemia after burning.