Heat preconditioning prevents enterocyte mitochondrial damage induced by surgical manipulation

Abstract

Background: The small intestine is 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, leading to mucosal damage. Heat preconditioning has been shown to offer protection against various stresses including oxidative stress and this study looked at the effect of heat preconditioning on surgical manipulation-induced intestinal mitochondrial alterations. Methods: Control and rats pretreated with heat were subjected to surgical manipulation by opening the abdominal wall and handling the intestine as done during laparotomy. Mitochondria were prepared from isolated enterocytes and structural and functional alterations were assessed. Results: Surgical manipulation of the intestine resulted in mitochondrial alterations as seen by ultrastructural changes and altered lipid composition. Mitochondria were functionally impaired as evidenced by altered calcium flux, decreased respiratory control ratio, and increased tetrazolium dye reduction and swelling. Along with this, biochemical alterations such as increased lipid and protein oxidation were seen following surgical manipulation. Mild heat preconditioning of the animal prevented these damaging effects. Conclusion: These studies suggest that stress in the small intestine due to surgery can affect enterocyte mitochondrial structure and function and these effects can be prevented by mild whole body hyperthermia prior to surgery.