A MURINE MODEL OF INTERLAMELLAR CORNEAL TRANSPLANTATION

Aims/background-There are more reagents and information available for immunological studies in the mouse compared with other animals. Unfort unately, the mouse penetrating keratoplasty model is associated with h igh background inflammation which hinders study of the immune response to the graft. To mitigate this drawback, a murine orthotopic corneal interlamellar transplantation model with mild non-specific inflammatio n was developed. Methods-A 1.5 mm diameter full thickness donor cornea l button was placed in a 2 mm diameter recipient corneal interlamellar pocket without placement of a suture. The clinical course of graft st atus was studied daily for 60 days in 30 allografts (donor strain CBA 101 (H-2(k)) to recipient NM (H-2(q))) and 30 syngeneic grafts (NM to NIH) by slit lamp biomicroscopy and scored for neovascularisation, opa city, oedema, and granularity. In another cohort of animals, histologi cal observation was performed after 30 minutes and on days 10, 20, 30, and 40 after transplantation (four allografts and four syngeneic graf ts per time point). Histological study was also performed on grafts wi thout donor epithelium and on interlamellar pockets without grafts. Re sults-There was significantly more neovascularisation (NV), opacity, o edema, and granularity in 24/30 allografts (80%) than in syngeneic gra fts. Such grafts were defined as rejected. The median time to rejectio n was 21 days (range 18 to >60 days). By histology, some allografts sh owed moderate to heavy cell infiltration which correlated with clinica l scores of NV (4-5), opacity (1-3), oedema (1-3), and granularity (1- 3). Such infiltration was absent in other allografts and syngeneic gra fts. Conclusion-Surgically, corneal interlamellar transplantation coul d be accomplished in the mouse and rejection could be clearly defined. The model can therefore be useful for in situ study of cell and molec ular aspects of corneal graft rejection.