NEUTROPHIL-MEDIATED INJURY IN ISCHEMIC SKIN FLAPS - AMELIORATION OF ISCHEMIC-INJURY BY CYCLOSPORINE IN THE RAT

The role of neutrophils, their presence, and their degree of infiltrat ion was examined in ischemic skin flaps, In a rat model, caudally base d dorsal flaps were studied and neutrophils were manipulated by giving cyclosporine at two different doses (15 and 30 mg per kilogram), admi nistrated either for 5 days as a pretreatment or 15 minutes before fla p elevation, The presence of neutrophils and lymphocytes in both intra vascular and extravascular space was assessed at 15, 30, and 60 minute s by skin biopsies, taken after elevation of the flap, by direct quant itative counting under the light microscope, The correlation between t he counts and localization of the neutrophils, but not the lymphocytes , and the percentage of necrosis showed an early and definite role of neutrophils on skin flap survival during ischemic insult, Cyclosporine -treated flaps showed a 24% to 37% increase in viability when compared to control flaps, These data suggest that neutrophils, probably their interactions and/or products, play an important role in ischemic flap survival, and cyclosporine A is able to inhibit neutrophil accumulati on and sequestration.