Heat preconditioning attenuates oxygen free radical-mediated alterations in the intestinal brush border membrane induced by surgical manipulation.

BACKGROUND The intestine is highly susceptible to free radical-induced damage and our earlier work has shown that surgical manipulation of the intestine results in generation of oxygen free radicals and mucosal damage along with alterations in the brush border membrane (BBM). Heat preconditioning is known to offer protection against various stresses including oxidative stress and this study looked at the effect of heat preconditioning on the intestinal BBM alterations following surgical manipulation. METHODS Control and rats heat preconditioned were subjected to surgical manipulation by opening the abdominal wall and handling the intestine. BBM were isolated from the intestine and structural and functional alterations to these membranes were assessed. RESULTS Surgical manipulation resulted in oxidative stress suggested by a decrease in alkaline phosphatase activity and alpha-tocopherol content, accompanied by an increase in lipid peroxidation. A decrease in glucose transport by the isolated BBM vesicles suggested functional impairment. Surgical manipulation resulted in phospholipid degradation with generation of arachidonic acid along with appearance of cPLA(2) in the membrane. These changes were prevented by heat preconditioning of the animal prior to surgical manipulation. CONCLUSION These results suggest that heat preconditioning offers protection from damage to the intestinal BBM following surgical manipulation and mild whole body hyperthermia might prevent postsurgical complications.