Protective effect of ischemic preconditioning on the jejunal graft mucosa injury during cold preservation

Abstract

Protection of intestinal graft mucosa during cold preservation is still an unmet need in clinical practice, thus affecting the success of transplantation. The present study investigates the ability of two ischemic preconditioning (IPC) procedures to limit cold preservation injury. Three groups of Sprague–Dawley rats were recruited (n=11 each) as follows: the short IPC (SIPC) performed through 4cycles of mesenteric ischemia of 4min each followed by 10min of reperfusion, the long IPC (LIPC) obtained by 2 ischemic cycles of 12min each followed by 10min of reperfusion, and the control group (C) without IPC. Grafts were then stored in cold histidine–tryptophan–ketoglutarate solution and samples were taken at 0, 3, 6 and 9h lasting preservation. Both IPC groups showed an advanced degree of preservation with delayed development of graft mucosa damage, mainly in the crypt region. At the beginning of preservation, the graft mucosa in both IPC groups showed lower degree of mucosal injury index (MII) by 50% in comparison with C group. Specifically, a significant improvement of MII was observed after 3h of preservation in the LIPC group (p<0.05) in comparison with untreated C grafts. Significant atrophy of the intestinal mucosa in C group was found after 3h of preservation (p<0.01), in SIPC group the progress of atrophy was delayed to 6h (p<0.001), and in LIPC group only moderate decrease in that was found. A parallel increase of laminin expression with the MII rate after 6 and 9h of preservation in comparison with the level at time 0 was observed in all grafts (p<0.001 and p<0.01, respectively). In both IPC groups the apoptotic cell (AC) rate was significantly reduced at the beginning of cold preservation (p<0.05 both). Moreover, in both the SIPC and C groups, the progressive increase in MII rate connected with AC rate decrease was due to a predominance of necrosis. By contrast in the LIPC group, after an increase of nearly 50% in the AC rate at the 3rd hour, its level remained fairly constant during the further 6h of preservation, thus probably preventing necrosis and improving graft viability.