Expression of IRFs and iNOS in the Mouse Cornea with Pseudomonas Aeruginosa Keratitis

ABSTRACT

PURPOSE: To investigate the expression of IRF-1, IRF-7 and iNOS in the mice model of Pseudomonas aeruginosa keratitis. The enzymatic activity of iNOS and its expression were also investigated. METHODS: With western blot analysis, the protein expression of IRF-1, IRF-7 (at 24 hours), and iNOS (at 12 hours and 24 hours) were evaluated in the mouse model of P. aeruginosa keratitis. iNOS enzymatic activity was determined with a scintillation counter. IRF-1 and IRF-7 expression were localized with immunofluorescent labeling. The wounded control group was given the same corneal wound without bacterial inoculation, and the fellow eyes served as normal controls. RESULTS: Expression of IRF-1, IRF-7 and iNOS was highly upregulated in corneas with P. aeruginosa keratitis compared to normal or wounded corneas. iNOS enzymatic activity also was higher in infected than normal corneas. In wounded corneas, NOS2 expression and activity slightly increased at 12 hours after the infection. Intense IRF-1 immunopositivity was seen in the epithelial layer of infected corneas. Some corneal stromal cells and endothelial cells showed moderate positive labeling in infected corneas. IRF-7 showed intense labeling in the epithelial layer and endothelial cells of normal as well as infected corneas. Increased IRF-7 labeling was observed in epithelial cells in the ulcerated region of infected corneas. CONCLUSIONS: These results suggest that IRF-1, IRF-7 and iNOS may play a regulatory role in the immune responses and wound healing process in P. aeruginosa keratitis.