Hyperoxygenated solution preconditioning attenuates lung injury induced by intestinal ischemia reperfusion in rabbits.

BACKGROUND: The current study was undertaken to elucidate the possible therapeutic effects of hyperoxygenated solution (HOS) preconditioning on lung injury induced by intestinal ischemia/reperfusion (I/R) in rabbits.

MATERIALS AND METHODS: Eighty rabbits were randomly divided into four groups (n = 20 each) as follows: (1) control group in which sham operation was performed (sham group), (2) HOS pretreatment group and sham operation (HOS + sham group), (3) ischemia/reperfusion group (I/R group), (4) HOS pretreatment and ischemia/reperfusion group (HOS + I/R group). Intestinal I/R model was produced by clamping superior mesenteric artery with an atraumatic vascular clamp for 1 h, and followed by reperfusion for 2 h. Animals in HOS + sham group and HOS + I/R group received intravenous HOS infusion (20 mL/kg, 10 mL/kg.h for 2 h) every day for 5 d before operation, and animals in sham group and I/R group received the same amount of normal saline in the same way. At the end of reperfusion, 8 animals from every group were sacrificed and histopathological changes of lung were observed; pulmonary edema, lung myeloperoxidase activity, superoxide dismutase activity, and malondialdehyde levels in lung tissues were also detected. The rest 12 animals in every group underwent 60 min of intestinal ischemia followed by 72 h of reperfusion, and effects of HOS pretreatment on survival in rabbits with lung injury induced by intestinal I/R was observed.

RESULTS: When rabbits were subjected to 60 min of intestinal ischemia, a high incidence of mortality was observed within 24 h. In this situation, HOS preconditioning before the start of ischemia/reperfusion significantly reduced the mortality. HOS preconditioning also decreased lung wet/dry ratio, neutrophil infiltration, lipid membrane peroxidation, and increased superoxide dismutase activity in the lungs after intestinal I/R compared with the I/R-treated rabbit lungs without HOS treatment. Histopathological analysis also indicated the effectiveness of HOS pretreatment.

CONCLUSIONS: HOS preconditioning could preserve superoxide dismutase activity, decrease lipid membrane peroxidation and neutrophil infiltration in the lungs, then ameliorate the deleterious changes in pulmonary injury induced by intestinal I/R.