Evaluation of delaying effects of different short-term dosage regimens of topical ciprofloxacin on corneal ulcer healing in an avian model

Background: Knowledge on possible delaying effects of topical ciprofloxacin on corneal ulcer healing is scarce in avian patients. Objectives: The study evaluates effects of different dosage regimens of topical ciprofloxacin on healing of corneal ulcer in an avian model. Methods: One hundred and fifty adult layers were randomly allocated into two equal categories each consisted of 5 groups (n = 15): 1, negative control (NC, normal cornea); 2, positive control (PC) (birds with experimental corneal ulcer); and 3, 4 and 5, birds with corneal injury that received ciprofloxacin 0.3% topically q6h, q8h and q12h, respectively for 3 (category 1) or 5 days (category 2). Corneas were excised for histopathological evaluation and determination of MMP-9 expression. Results: While no significant difference was observed in daily-measured fluorescein-stained ulcer size among ciprofloxacin-treated birds and PC group in category 1, birds in PC group of category 2 had significantly smaller ulcers as compared to antibiotic-treated birds at the end of experiment (p < 0.01 for all cases). Histopathological evaluations at the end of the experiment showed no significant difference among PC and ciprofloxacin-treated birds of both categories for almost all of the assayed parameters. Over expression of MMP-9 mRNA was observed in PC group after 3 and 5 days of ulcer induction compared to NC groups. Its expression in ciprofloxacin-treated birds of both categories remained close to PC groups. Conclusions: While ciprofloxacin administration for 3 days does not affect ulcer healing, it delays healing process at the end of 5 days of treatments in an avian model of corneal ulcer injury. This delaying effect is not associated with a drastic change in MMP-9 expression.