Effects of the antiprotease ulinastatin on mortality and oxidant injury in scalded rats.

BACKGROUND Proteolysis and oxidant injury are important mechanisms of injury in thermal burns. The glycoprotein ulinastatin has antiprotease and free radical-scavenging properties and therefore could be useful in the treatment of these injuries. OBJECTIVE To determine the free radical-scavenging effects of ulinastatin on rats with thermal injury. DESIGN An experimental study. MATERIALS AND INTERVENTIONS Sixteen rats with a 70% surface area immersion scald were treated intravenously for 3 hours; immediately after injury, the rats were treated with ulinastatin, 100,000 U/kg, in lactated Ringer's injection. Sixteen control rats were also scalded but were given only lactated Ringer's injection. Sixteen additional sham control rats were immersed in 37 degrees C water and given ulinastatin. MEASUREMENTS Levels of malondialdehyde, superoxide dismutase, lactate, and pyruvate in skin, along with the water content of the skin, were measured before injury and at intervals thereafter in six rats from each group. RESULTS The mortality rate was 50% at 72 hours and 90% at 14 days in scalded control rats, but it was 0% at 72 hours and 20% at 14 days in the treated rats (P < .01). Levels of malondialdehyde and superoxide dismutase in the skin and the lactate-pyruvate ratio all remained at the same values (as those before scalding) in treated rats but rose in the skin of scalded control rats (P < .05 for each). The water content of scalded skin gradually increased after injury in all groups, but at 3 hours, the scalded skin in treated rats contained less water than that in scalded control rats (P < .05). CONCLUSION Ulinastatin may have a therapeutic role in treating thermal injuries.