INHIBITION OF INTERLEUKIN-8 (IL-8) ACTIVITY PREVENTS RENAL FUNCTION DETERIORATION DUE TO ISCHEMIA/REPERFUSION IN SYNGENEIC AND ALLOGENEIC RAT KIDNEY TRANSPLANTATION.

P63 Ischemia-reperfusion (I/R) injury after organ transplantation is a major cause of delayed graft function and is now known to involve recruitment and activation of inflammatory cells. The signals mediating leukocyte recruitment and activation include upregulation of adhesive molecules and production of chemokines such as IL-8. Here we examined the effect of pharmacological blocking of IL-8 activity with DF1681B, a small organic inhibitor of IL-8 (Dompè SpA, Italy), in preventing renal function deterioration and intragraft neutrophil infiltration due to I/R injury in a model of rat kidney transplantation. Kidneys from Lewis rats were placed in an iced Belzer (UW) solution for 4 hr and then transplanted into syngeneic or allogeneic (Brown Norway rats) binephrectomized recipients. An increase of IL-8 mRNA expression (by real-time PCR) with a peak at 3hr after I/R both in syngeneic (p<0.01) and allogeneic groups (p<0.05) was associated with a marked infiltration of neutrophils (by immunofluorescence) in renal tissue. DF1681B (5, n=5, 15, n=6 or 30 mg/kg n=3) or saline (n=8) was given three times to syngeneic recipient rats: before transplant (at -24hr or -8hr or -2hr i.v.), immediately before reperfusion (i.v.) and 2hr (s.c.) later. The renal function was assessed by measuring serum creatinine concentration at 16hr and 24hr after the transplant. At the dose of 15mg/kg DF1681B, serum creatinine levels were significantly reduced (p<0.01) in rats pretreated at -24hr, -8hr, -2hr in respect to control animals. Also granulocyte graft infiltration was significantly reduced with pretreatment at –24hr and –8hr (p<0.05). Intermediate effects were observed with 5mg/Kg, whereas the dose of 30mg/kg had toxic effects including severe inflammation at the site of injection and hematuria. From these results and with respect to future clinical applications of the protocol, we found that the pretreatment at –8hr with the dose of 15mg/kg of DF1681B was the most effective in preventing renal I/R injury. To investigate whether the treatment was of benefit also in allogeneic transplantation, 15mg/kg of DF1681B was administred to BN rats 8hr before surgery, immediately before reperfusion and 2hr later. DF1681B prevented the serum creatinine level increase both at 16 and 24hr post-transplant. Granulocyte graft infiltration was also reduced. °p<0.05 vs allogeneic control; #p<0.05 vs syngeneic control; mean±SE The efficacy of DF1681B to modulate ischemia/reperfusion injury in the rat kidney transplant model opens new perspectives for preventing post-transplant delayed graft function.