PPARα Agonist Suppresses Inflammation after Corneal Alkali Burn by Suppressing Proinflammatory Cytokines, MCP-1, and Nuclear Translocation of NF-κB

We investigated the effect of a peroxisome proliferator-activated receptor α (PPARα) agonist after corneal alkali injury. Fenofibrate 0.05% (PPARα agonist group) or vehicle (Vehicle group) was topically instilled onto the rat cornea after injury. Histological, immunohistochemical, and real-time reverse transcription PCR analyses were performed. PPARα-positive cells were observed among basal cells of the corneal epithelium in normal and alkali-burned corneas. The number of infiltrating neutrophils and macrophages at the corneal limbus was lower in the PPARα agonist group. Interleukin-1β (IL-1β), IL-6, IL-8, monocyte chemoattractant protein-1 (MCP-1), and vascular endothelial growth factor-An mRNA expression was suppressed in the PPARα agonist group compared to the Vehicle group. mRNA levels of nuclear factor kappa B (NF-κB) in corneal tissue were not different. However, NF-κB was expressed in the cytoplasm of basal cells in the PPARα agonist group and in the nucleus in the Vehicle group. MCP-1 was more weakly expressed in the PPARα agonist group. The PPARα agonist inhibited inflammation during the early phase after injury. Anti-inflammatory effects of the PPARα agonist included prevention of up-regulation of proinflammatory cytokines and MCP-1, and prevention of inflammatory cell infiltration into the injured cornea. Thus, a PPARα agonist may be a promising treatment for corneal injury.