EFFECT OF PREINDUCTION OF HEAT-SHOCK PROTEINS ON INDOMETHACIN-INDUCEDSMALL-INTESTINAL LESION IN RATS

Systemic hyperthermia induces the synthesis of heat shock proteins (HS Ps) in several organs. However, the mechanism of induction and the fun ctions of HSPs in the small-intestinal mucosa have not been establishe d. We examined the expression of HSPs in the small-intestinal mucosa a fter systemic hyperthermia, and evaluated the cytoprotective function of preinduced HSPs on experimentally induced mucosal damage. HSP expre ssion was investigated by Western blot and densitometric analysis befo re and after hyperthermia (42.5 degrees C; 20 min). Expression of a 72 -kDa heat shock protein (HSP72) and a 73-kDa heat shock protein (HSP73 ), both of which are endogenous cytoprotectants in vitro significantly increased, peaking 6-9h after hyperthermia, without any pathologic al terations, whereas the expression of a 60-kDa heat shock protein (HSP6 0) did not increase. To investigate the influence of pre-induction of HSPs on small-intestinal damage, rats received indomethacin (10mg/kg; orally) with or without pre-treatment with hyperthermia. Small-intesti nal damage caused by indomethacin was not influenced by pre-induction of HSP72 and HSP73. We demonstrated that systemic hyperthermia induced HSP72 and HSP73, although pre-induction of these proteins did not hav e a cytoprotective function in the small-intestinal damage caused by i ndomethacin.