Presence of polymorphonuclear granulocytes during the early stage of transplant arteriosclerosis after prolonged ischemia in the rat.

Abstract

The presence and function of polymorphonuclear granulocytes has been investigated, in particular, in the microcirculation in many short-term models of ischaemia/reperfusion injury. The aim of this study was to examine the presence of granulocytes in the aorta in a recently established long-term model of transplant arteriosclerosis, based on prolonged cold graft ischaemia time in the rat. Aortic grafts of PVG donors were subjected to two different cold ischaemia times of 1 and 4 h (n = 5 in each group) before an orthotopic transplantation to syngeneic recipients. The grafts were explanted shortly after various times post-reperfusion (7.5 min 24 h) and examined with conventional staining, immunohistochemistry and transmission electron microscopy for the presence of granulocytes. The results showed the presence of these cells adherent to the endothelial layer or in the subendothelial layer in grafts with both ischaemia times and with a maximum seen 2 h after transplantation. The internal elastic lamina was interrupted at sites of granulocyte adherence. We concluded that the polymorphonuclear granulocyte may be involved in the ischaemia/reperfusion injury in this model, thus, contributing to the development of accelerated transplant arteriosclerosis.