OBJECTIVETo study the antagonism of Zn-metallothionein (Zn-MT) to oxidative stress of rats with severe scalding after delayed resuscitation.

METHODS27 Wistar rats were randomly divided into three groups: normal control; burn with delayed fluid resuscitation group; and Zn-MT protected group. The rats were scalded with 30% total body surface area (TBSA) third degree burn. Four hours after injury, they were resuscitated, but Zn-MT (1 x 10(-5) mol/L) was given in the third group rats. 24 hours after they were scalded, blood was taken, RBCs were separated and labeled with electron spin resonance (ESR) spin label 3-maleimido-proxy l to detect membrane protein conformation. The serum was collected and added into the reaction system of xanthine, xanthine oxidase and ESR spin trap 5, 5-dimethylpyroline-N-oxide to assay the levels of superoxide dismutase (SOD) by ESR.

RESULTSThe ratios of strong solidity and weak solidity of RBC membrane proteins in the three groups were 0.352 +/- 0.043, 0.409 +/- 0.027, and 0.386 +/- 0.062 respectively, and the revolved times of membrane proteins were 1.300 +/- 0.210, 1.576 +/- 0.190 and 1.381 +/- 0.210 seconds respectively. Compared to the first group, the membrane protein conformation in the second group was changed remarkably, and the speed of membrane protein movement decreased significantly. However, those changes were alleviated obviously by Zn-MT. The SOD levels in serum of the three groups rats were 73.2% +/- 1.4%, 48.8% +/- 3.8% and 66.8% +/- 3.2% respectively. Compared to the normal control group, the SOD levels in serum of the second group decreased obviously. However, an excess of oxygen free radicals produced after injury could be scavenged by Zn-MT.

CONCLUSIONRBC membrane proteins of rats with severe scalding after delayed resuscitation were injured by oxygen free radicals produced after injury, and Zn-MT could alleviate this injury.