Effects of Heat Shock Preconditioning on Oxygen Free Radicalin Gastric Mucosa of Burned Rats

Objective:To observe the influence of heat shock preconditioning on oxygen free radical(OFR) and the expression of heat shock protein(HSP)70 in gastric mucosa of severely burned rats in order to investigate its protective mechanism on burn-induced acute gastric mucosal lesion.Methods:Ninety-six Wistar rats were divided into two groups: burn(B) and heat shock preconditioning before burn(HB).The rats in two groups were sacrificed and laparotomized at each time point.The extent of gastric mucosal lesions(UI) was evaluated.The superoxide dismutase(SOD) and malondialdegyde(MDA) levels in gastric mucosa of burned rats were also determined.Immunohistochemical method was used to analyze the expression of HSP 70.Results: After burn injury,the activity of superoxide dismutase(SOD) decreased and the production of MDA obviously increased in rat gastric mucosa as the time elapses.The rats in B group were induced conspicuous gastric mucosal lesions,while UI in HB group was significantly lower.The expression of HSP 70 was significantly increased in HB group compared with those in B group.Heat shock preconditioning could reduce the massive consumption of SOD and production of MDA obviously increased in gastric mucosa.A positive correlation was shown between UI and MDA(r=0.695,P0.01),between SOD and HSP 70(r=0.527,P0.05).A negative correlation existed between SOD and MDA(r=-0.823,r=-0.794,P0.01).Conclusion:These results suggested that there exists OFR injury in gastric mucosa of burned rats.Heat shock preconditioning could ameliorate OFR injury in burned rats.The protective machanisms are related to the protection of superoxide dismutase by HSP 70.