LONG-TERM SURVIVAL OF SKIN ALLOGRAFTS IN RATS TREATED WITH TOPIC AL CYCLOSPORINE

The study investigated the effects of topical cyclosporine (CsA) on skin allografts in rats, finding that untreated allografts were rejected in about 7.4 days, while those treated with CsA survived significantly longer, depending on the dosage and duration of treatment. Continuous CsA treatment at 10 mg/rat/day or similar regimens resulted in long-term graft survival exceeding 100 days. The therapeutic blood level of CsA was between 250 to 500 ng/ml, with most grafts being rejected when levels fell below 200 ng/ml. Direct application of CsA on allografts led to longer survival compared to application on distant skin. The study highlighted that high local concentrations of CsA were crucial for prolonging graft survival, with minimal cell infiltration and hair follicle loss observed in long-surviving grafts.