Evaluation of Early Markers of Ischemia-reperfusion Injury and Preservation Solutions in a Modified Hindlimb Model of Vascularized Composite Allotransplantation

BACKGROUND. Ischemia-reperfusion injury plays an important role in vascularized composite allotransplantation (VCA). Currently, there is no ideal preservation solution for VCA. In this study, we investigated the effects of 4 different preservation solutions on different tissues within an allogeneic hindlimb rat model. METHODS. Sprague Dawley rat hindlimbs were flushed and placed at 4°C for 6 h in heparinized saline, histidine-tryptophan-ketoglutarate, University of Wisconsin (UW), and Perfadex and heterotopically transplanted for ease of ambulation. Apoptosis, necrosis, and the extracellular matrix of the tissues within the allograft were analyzed 2 h posttransplantation using immunohistochemistry, terminal deoxynucleotidyl transferase 2'-deoxyuridine 5'-triphosphate nick-end labeling (TUNEL) assay, and enzyme-linked immunoassay. RESULTS. Higher expression of cleaved caspase 3, a significant increase of high-mobility group box 1 and TUNEL-positive apoptotic cells were observed in the muscle and vessels preserved with heparinized saline compared with UW and Perfadex following reperfusion. Higher expression of TUNEL-positive apoptotic cells was observed in the skin at 12 h of ischemia and in the nerve following reperfusion with histidine-tryptophan-ketoglutarate as a preservation solution. CONCLUSIONS. Our data suggest that UW and Perfadex are preferred solutions in VCA. The vessels within the allografts appear to be very susceptible, with laminins and CD31 playing a role in ischemia-reperfusion injury.