Abstract: Objective To investigate the effects of ursolic acid on corneal graft rejection in a rat model of othotopic corneal
allograft transplantation. Methods Forty-eight recipient Wistar rats were divided into normal control group with saline
treatment (group A), autograft group with saline treatment (group B), SD rat allograft group with saline treatment (group C),
and SD rat allograft group with intraperitoneal ursolic acid (UA) treatment group (group D). The rats received saline or UC
(20 mg·kg-1 ·d-1) treatment for 12 days following othotopic graft transplantation. The grafts were evaluated using the Larkin
corneal rejection rating system, and the graft survival was assessed with Kaplan-Meier analysis. On day 14, the grafts were
harvested for histological examination, Western blotting, and assessment of expressions of interlukin-2 (IL-2), interferon-γ
(IFN-γ), nuclear transcription factor-κB (NF-κB) p65, vascular endothelial growth factor (VEGF) and intercellular adhesion
molecule-1 (ICAM-1). Results The allograft survival was significantly longer in group D than in group C (29.12±9.58 vs 9.67±
2.16 days, P<0.05). UC treatment obviously reduced the expression levels of IL-2, IFN-γ, NF-κBp65, ICAM-1 and VEGF and
increased inhibitory kappa B alpha (IκB-α) expression in the grafts, where no obvious inflammatory cell infiltration or corneal
neovascularization was found. Conclusion As a NF-κB inhibitor, ursolic acid can prevent corneal neovascularization and
corneal allograft rejection to promote graft survival in rats following orthotopic corneal allograft transplantation.