Modulation of peripheral-type benzodiazepine receptor levels in a reperfusion injury pig kidney-graft model

Background. Ischemia-reperfusion injury is associated with an increased risk of acute rejection, delayed graft function, or chronic graft dysfunction. Mitochondria play a central role in this process. Methods. Using an autotransplantation pig kidney model, both early (40 min and 7 days) and late (2-16 weeks) changes in renal function and morphology were determined after different periods of cold ischemia in University of Wisconsin or Euro-Collins solutions. We have also investigated the expression of the peripheral-type benzodiazepine receptor (PBR), which is also critical in maintaining outer mitochondrial membrane stability. Results. Function of the kidneys was better preserved after 1 hr and 24 hr than after 48 hr and 72 hr in Euro-Collins and University of Wisconsin solutions. Medulla injury was reduced in I hr-preserved and 24 hr preserved groups. PBR was found to be present in epithelial cells of the deep cortical and outer medulla in both normal human and well-preserved pig kidneys. PBR expression was modulated by ischemia-reperfusion injury and the concurrent tubular injury and repair processes. Conclusion. This study indicates that PBR expression correlates with the quality of kidney preservation and might serve as an index of kidney and mitochondria viability. Moreover, these data suggest that PBR might be involved in membrane biogenesis during reperfusion. In addition, considering the identical localization of PBR in human and pig kidneys, these findings could have a direct application in human clinical settings of kidney pathology.