Protective effect of L-arginine preconditioning on ischemia and reperfusion injury associated with rat small bowel transplantation.

To investigate the protective effect and possible mechanism of L-arginine preconditioning on ischemia and reperfusion injury associated with small bowel transplantation (SBT). Male inbred Wistar rats weighting between 180 and 250 g were used as donors and recipients in the study. Heterotopic rat SBT was performed according to the techniques of Li and Wu. During the experiment, intestinal grafts were preserved in 4 degrees Ringer's solution for 8 h before being transplanted. Animals were divided into three groups. In group 1, donors received intravenous L-arginine (50 mg/kg, 1 mL) injection 90 min before graft harvesting. However, donors in control group were given normal saline (NS) instead. In group 3, six rats were used as sham-operated control. Specimens were taken from intestinal grafts 15 min after reperfusion. Histological grading, tissue malondialdehyde (MDA) and myeloperoxidase (MPO) levels were assessed. The graft survival of each group was monitored daily until 14 d after transplantation. Levels of MDA and MPO in intestine of sham-operated rats were 2.0+/-0.22 mmol/g and 0.66+/-0.105 U/g. Eight hours of cold preservation followed by 15 min of reperfusion resulted in significant increases in tissue MDA and MPO levels. Pretreatment with L-arginine before graft harvesting resulted in lower enhancement of tissue levels of MDA and MPO and the differences were significant (4.71+/-1.02 mmol/g vs 8.02+/-3.49 mmol/g, 1.03+/-0.095 U/g vs 1.53+/-0.068 U/g, P<0.05). Besides, animals in L-arginine pretreated group had better histological structures and higher 2-wk graft survival rates comparing with that in NS treated group (3.3+/-0.52 vs 6+/-0.1, 0/6 vs 6/6, P<0.05 or 0.01). L-arginine preconditioning attenuates ischemia and reperfusion injury in the rat SBT model, which was due to antioxidant activities partially.