Specimens of the distal ileum were collected from each group of animals at the end of the reperfusion period to determine the level of tissue damage. Following overnight fixation in 10% formalin, samples of ileum were embedded in paraffin. Sections (4 µm) were stained with hematoxylin and eosin. Microscopic histological damage score was evaluated by a person unaware of the treatments and was based on a semi-quantitative scoring system in which the following features were graded: damage of epithelium (0 morphologically normal; 1 development of subepithelial space; 2 presence of subepithelial space with moderate lifting of epithelial layer; 3 severe epithelial lifting), inflammatory cells infiltration (0 absence of infiltrate or less than five cells; 1 mild infiltration to the lamina propria; 2 moderate infiltration to the muscularis mucosae and submucosa; 3 severe transmural infiltration involving the muscle layer), extent of muscle thickening (0 normal; 1 moderate; 2 severe), edema (0 no edema; 1 zonal edema in lamina propria and submucosa; 2 diffuse edema in lamina propria and submucosa). Data were expressed as sum of scores for each feature (total score).