Injury from oxygen free radicals has been suggested to be of greater significance in the preservation of small intestine than of other organs. To determine if using the free radical scavenger, superoxide dismutase (SOD), with University of Wisconsin (UW) solution would improve preservation of small intestine, acute and chronic studies were conducted. Thirty-centimeter segments of small intestine from Lewis rats were flushed with and stored in Collins, UW, or SOD-modified (8000 U/ml) UW solution at 4°C for 18 hr. For the acute study, small intestine segments were subsequently reperfused using support rats. The support rats in the UW/SOD group also received SOD (1750 U, iv) at the onset of reperfusion of small intestine. After 2 hr of reperfusion, maltose absorption and weight gain of small intestine were determined. For the chronic study, small intestine segments were transplanted as isografts. SOD (1750 U, iv) was also given to recipients prior to reperfusion of grafts in the UW/SOD group. Long-term effects were determined by recipient survival for at least 17 days. Results showed the small intestine in the UW/SOD group had the best recovery of mucosal absorption (256 ± 39 versus 202 ± 21 in the UW group and 153 ± 14 glucose mg/dl in the Collins group, P < 0.01), the least percentage weight gain (19 ± 3% versus 25 ± 5% in the UW group and 38 ± 5% in the Collins group, P < 0.01), and the best 17-day survival rate ( 9 12 versus 2 9 in the UW group, P < 0.025, and 0 8 in the Collins group, P < 0.01) among the three groups. Histological examination of the UW/SOD group revealed minimal injury, with the best preservation of mucosa and vasculature. We, therefore, conclude that the use of SOD in conjunction with UW solution results in significant improvement in the recovery of absorptive function, morphology, and transplant survival of small intestine after extended preservation. This suggests the importance of amelioration of free radical-induced injury in maintaining the integrity of preserved small intestine.
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