Effect of a cyclosporine A delivery system in corneal transplantation

Objective To test the immunosuppressive effect of cyclosporine (Cs) in a polymer placed in the anterior chamber of corneal allograft recipients. Methods Wistar inbred rats with vascularized corneas were recipients of corneal allograf ts from Sprague- Dawley donor rats. Rats underwent penetrating keratoplasty an d were divided randomly into four groups: untreated control animals (UCA); Cs- pol ymer anterior chamber recipients (CPA); co- polymer subconjunctival recipient s (CPS); and Cs- olive oil drop recipients (COO). Grafts were examined by s lit lamp every 3 days and clinical conditions were scored. Cs concentration in the aqueous humor was assayed at 1, 2, and 4 weeks. At 1, 2 and 4 weeks after transplantation, the operated eyes were collected for histopathological evaluat ion of the grafts. Results The median survival time of the allografts was 8. 2±1. 48 days for the UCA grou p, 11. 4±2. 50 days f or the CPS group, and 17. 0±2. 00 days for the CPA group. There was a statist ically s ignificant difference (P<0. 05) between survival time of the allografts in t he animals of the CPA group compared to the other groups of graft recipients. Significantly higher concentrations of Cs were found in the eyes given an anteri or chamber implant of Cs- polymer, compared to other treatment groups or untreat ed rats. A transient inflammatory response in the anterior chamber was observe d in the CPA group. Conclusions Cs- polymer placed in the anterior chamber significantly prolongs corneal allogr aft survival time in a high risk corneal graft rejection model. This intraocul ar delivery system may be a valuable adjunct for the suppression of immune graft rejection.