Preservation injury and acute rejection of rat intestinal grafts: Protection afforded by pyruvate

Pyruvate has been shown to prevent intestinal mucosal inj un; after ischemi a-reperfusion. The aim of the present study was to determine whether pyruva te can (1) prevent postreperfusion mucosal injury occurring after intestina l preservation and subsequent transplantation and (2) exert a protective ef fect on the intestinal graft mucosa during acute rejection. Preservation mu cosal injury was evaluated, after 2 hours of reperfusion, by comparing graf ts transplanted in a rat syngeneic combination (ACI to ACI) after 2 hours o f cold preservation using pyruvate (n = 6) or placebo (n = 6). Mucosal para meters obtained during acute rejection (allogeneic combination: ACI to Lewi s) were compared between placebo-treated (n =6) and pyruvate-treated (n = 6 ) animals. Tissue injury was evaluated by histopathologic examination, oxyg en free radical production by luminol-enhanced chemiluminescence, and degre e of neutrophil infiltration by myeloperoxidase staining. After reperfusion of the preserved grafts and during acute rejection, mucosal oxygen free ra dical levels and the number of infiltrating neutrophils were significantly (P <0.05) increased in the untreated grafts, whereas there was a statistica lly significant inhibition of these parameters in those treated with pyruva te. Mucosal injury; seen after reperfusion of the preserved grafts, was pre vented by pyruvate. The histopathologic abnormalities observed in the untre ated grafts during rejection were also significantly reduced bq; pyruvate. Treatment with pyruvate before cold preservation of intestinal grafts, in t his rat model, reduced reperfusion mucosal injury, neutrophil infiltration, and oxygen free radical production. Oxygen free radicals n ere produced in the mucosa of the graft during acute rejection and their production was re duced by pyruvate, which exerted a protective effect on the rejecting allog raft mucosa.