The effect of propolis extract in experimental chemical corneal injury

Purpose: To investigate the effect of propolis, a natural resin produced by honeybees, in the treatment of alkali-injured rabbit eyes. Method: A corne al alkali burn was induced by applying filter paper immersed in 1 N NaOH on the central axis of the right corneas of 24 rabbits for 30 a. The animals were divided into three treatment groups: group 1 (control) was given 0.3% tobramycin and phosphate-buffered solution; group 2 was treated with antibi otic coverage and topical 1% ethanolic extract of propolis; group 3 receive d antibiotic coverage and topical 1% dexamethasone. The dexamethasone-treat ed group was maintained as the positive control. Drugs were instilled 4 tim es a day for 7 days. The corneal inflammation was evaluated by calculating the average inflammatory index obtained from clinical observation of the ci liary hyperemia, central and peripheral corneal edema at 24 h, 48 h, on day 5 and day 7, before sacrificing the animals. Then, the corneas underwent r outine histological examination. Results: The effects of dexamethasone and propolis on healing of injured corneas were similar (p > 0.05) and signific antly better than controls at 24 h (p < 0.01, p < 0.05, respectively), and on day 7 (p < 0.05) with respect to the inflammatory index. On histological observation, inflammatory cell infiltration was lower as compared to contr ol in both the dexamethasone and propolis groups (p < 0.001) and similar wi th each other (p > 0.05). Conclusions: Our study shows that propolis has an anti-inflammatory effect comparable to dexamethasone in chemical corneal i njury. Copyright (C) 2000 S .Karger AG, Basel.