OBJECTIVETo observe the harmful effects of oxygen free radicals and the protective roles of Tiopronin in severely scalded rats after delayed fluid resuscitation.

METHODSRats inflicted with 30% III degree scald on the back were employed as the model. They were divided into delayed resuscitation (D) and Tiopronin treatment (T) groups. The changes in superoxide dismutase (SOD) and malonyldialdehyde (MDA) in plasma and subeschar fluid were determined at 24 to 48 postburn hours (PBHs) by means of electron spin resonance (ESR) technique and other routine methods. And the pathomorphological changes in the heart, liver, kidneys and small intestine, and changes in the blood biochemical indices were simultaneously determined. Normal rats were taken as control group (N).

RESULTSThe plasma SOD level was was lower than that in N group, while the MDA content in plasma and subeschar fluid in D group was much higher than that in N group. Changes in all the blood biochemical and internal organ pathomorphology were more obvious in the D group. on the other hand, the rat plasma SOD level in T group increased obviously (P < 0.01) while the MDA contents was decreased in T group (P < 0.05) when compared with those rats of D group. In addition, the internal organ pathomorphology and blood biochemical indices were improved evidently in T group.

CONCLUSIONOxidative stress injury was evoked in severely scalded rats after delayed fluid resuscitation, and it could be protected to some extent by Tiopronin.