Background. The protective effects of carbon monoxide (CO) against ischemia/reperfusion (IR) injury during organ transplantation have been extensively investigated. Likewise, CO-releasing molecules (CORMs) are known to exert a variety of pharmacological activities via liberation of controlled amounts of CO in organs. Therefore, we hypothesized that intraluminal administration of water-soluble CORM-3 during cold storage of intestinal grafts would provide protective effects against IR injury. Methods. Orthotopic syngeneic intestinal transplantation was performed in Lewis rats following 6 h of cold preservation in Ringer solution or University of Wisconsin solution. Saline containing CORM-3 (100 µmol/L) or its inactive counterpart (iCORM-3) was intraluminally introduced in the intestinal graft before cold preservation. Results. Histopathological analysis of untreated and iCORM-3-treated grafts revealed a similar erosion and blunting of the intestinal villi. These changes in the mucosa structure were significantly attenuated by intraluminal administration of CORM-3. Intestinal mucosa damage caused by IR injury led to considerable deterioration of gut barrier function 3 h postreperfusion. CORM-3 significantly inhibited upregulation of proinflammatory mRNA levels, ameliorated intestinal morphological changes, and improved graft blood flow and mucosal barrier function. Additionally, CORM-3-treated grafts increased recipient survival rates. Pharmacological blockade of soluble guanylyl cyclase activity significantly reversed the protective effects conferred by CORM-3, indicating that CO partially mediates its therapeutic actions via soluble guanylyl cyclase activation. Conclusions. Our study demonstrates that luminally delivered CORM-3 provides beneficial effects in cold-stored rat small intestinal grafts and could be an attractive therapeutic application of CO in the clinical setting of organ preservation and transplantation.
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