Background  

Long-term application of topical steroids following penetrating keratoplasty is disadvantageous due to side effects (steroid response, cataract, surface disorders). In this study we investigated the efficacy of topical pimecrolimus regarding clear graft survival following allogeneic orthotopic keratoplasty in rats.

Methods  

A total of 46 penetrating keratoplasties were performed using Fisher rats (allogeneic groups) and Lewis rats (syngeneic group) as donors and Lewis rats as recipients: group 1 (n = 11), allogeneic control without therapy; group 2 (n = 12), syngeneic control; group 3 (n = 11), mycophenolate mofetil (MMF) 40 mg/kg body weight; group 4 (n = 12), pimecrolimus 1% ointment twice daily. Four animals of each group were sacrificed for immunohistological evaluation on day 14. Therapy was administered for 18 days. The grafts were evaluated once every 3 days regarding opacity, oedema and vascularisation. Graft rejection was defined as total graft opacity.

Results  

Mean rejection-free graft survival was 11.4 days in group 1 (allogeneic control), 100 days (total follow-up time) in group 2 (syngeneic control), 24.0 days in group 3 (MMF 40 mg/kg) and 11.6 days in group 4 (topical pimecrolimus). The immunohistological evaluation showed no statistically significant difference in cell infiltration of the grafts comparing groups 1 and 4.

Conclusions  

Topical immunosuppression with pimecrolimus does not prolong graft survival in the allogeneic keratoplasty rat model.