Oxygen Insufflation in University of Wisconsin Solution Ameliorates Reperfusion Injury in Small Bowel after Cold Storage and Reperfusion

Background: Results in small bowel transplantation are inferior compared to other solid organ transplantations, among other reasons, due to a specific vulnerability to ischemia/reperfusion injury. New strategies are needed to improve organ storage. Here we compare static cold storage in University of Wisconsin solution to storage supplemented with molecular oxygen gas insufflation. Material/Methods: Rat small bowel was retrieved and either stored unoxygenated (UW) or oxygenated (UW+O-2) for 18 h at 4 degrees C Biochemical parameters, mucosal function, Toll-like receptor upregulation, and parameters of structural integrity were evaluated following isolated reperfusion in vitro for 30 min at 37 degrees C. Results: Oxygenation showed: ATP concentration was 82 times higher; lactate dehydrogenase release was continuously lower over 30 min; malondialdehyde, a final product of lipid peroxidation (UW+O-2 vs. UW; 2.7 +/- 0.92 nmol/mL vs. 17.22 +/- 10.1 nmol/mL; P<0.05) and nitric oxide concentration (0.87 +/- 0.27 mu mol/L vs. 2.17 +/- 0.29 mu mol/L; P<0.001) were significantly lower; whereas mucosal functional integrity (galactose uptake) was better preserved (0.47 +/- 0.18 mg/dL vs. 0.35 +/- 0.05 mg/dL). Amelioration of tissue damage could be demonstrated by reduced apoptosis (3.3 +/- 1.2 AU vs. 28.4 +/- 10 AU; P>0.05), and preserved subcellular integrity. Toll-like receptors were significantly less upregulated (TLR2 0.32 +/- 0.1 vs. 2.1 +/- 1.5-fold and TLR4 1.53 +/- 1.14 vs. 11.79 +/- 5.4-fold; P<0.05). Conclusions: Oxygenated storage is superior to standard storage in University of Wisconsin solution in terms of energetics, tissue damage, and mucosal integrity.