Experimental model of mesenteric ischemia: reperfusion by abdominal aorta clamping in Wistar rats.

OBJECTIVE To develop an experimental model of global normothermic ischemia able to demonstrate the transient ischemia and reperfusion periods required for development of ischemia/reperfusion injury in the small intestines of Wistar rats by clamping the abdominal aorta. METHODS Twenty adult male Wistar rats weighing 250-350g were randomly divided into five groups with four rats each and submitted to increasing times of ischemia (0 - 30 - 45 - 60 - 90 minutes). Within each group, except the control one, two rats underwent 60 minutes of reperfusion and two 90 minutes. After the procedures, histological analysis was conducted by measurement of areas of necrosis. RESULTS The degree of intestinal necrosis ranged from 15% to 54% (p = 0.0004). There was progressive increase in the degree of injury related to increase in ischemic time. However, greater degrees of injury were observed in the lowest times of reperfusion. The analysis of the coefficient of variation of necrosis among the ten groups of ischemia/reperfusion showed a statistically significant difference in 15 areas, 13 related to the control group. CONCLUSION The model was able to show the periods required for the occurrence of ischemia/reperfusion injury by aortic clamping and can serve as a basis to facilitate the development of studies that aim at understanding this kind of injury.