Increase of corneal graft survival by use of topically immunosuppressive agents in rabbits

Corneal graft survival in rabbits was significantly prolonged by topical treatment of the recipient eye with cyclophosphamide (0.1% in sterile isotonic NaCl) and methotrexate (0.1% in arachis oil) applied four times daily for 4 weeks. A control group of animals was treated with dexamethasone in the same way. The mean graft survival time was 52 +/- 18.5 days in the group treated with dexamethasone and 80 +/- 18.2 and 73 +/- 23.5, respectively, in the groups treated with cyclophosphamide and methotrexate. Cyclophosphamide and methotrexate applied topically produced no systemic side effects, and only one mild and transient local side effect in the form of hyperemia of the bulbar and palpebral conjunctiva. These two immunosuppressive drugs were more effective than the corticosteroid currently in clinical use, i.e., dexamethasone.