Anti-inflammatory and antioxidant effects of Tualang honey in alkali injury on the eyes of rabbits: Experimental animal study

Background: Alkali injury is one of the most devastating injuries to the eye. It results in permanent unilateral or bilateral visual impairment. Chemical eye injury is accompanied by an increase in the oxidative stress. Antiinflammatory and antioxidant agents play a major role in the treatment of chemical eye injuries. The purpose of this study is to evaluate the anti-inflammatory (clinical and histopathological) and antioxidant effects of Tualang honey versus conventional treatment in alkali injury on the eyes of rabbits. Methods: A preliminary study was carried out prior to the actual study to establish the alkali chemical injury on rabbit's cornea and we found that alkali chemical injury with 2 N NaOH showed severe clinical inflammatory features. In actual study, alkali injury with 2 N NaOH was induced in the right eye of 10 New Zealand White rabbits' cornea. The rabbits were divided into two groups, Group A was given conventional treatment and Group B was treated with both topical and oral Tualang honey. Clinical inflammatory features of the right eye were recorded at 12 hours, 24 hours, 72 hours, 5(th) day and 7(th) day post induction of alkali burn on the cornea. The histopathological inflammatory features of the right corneas of all rabbits were also evaluated on day-7. The level of total antioxidant status and lipid peroxidation products in the aqueous humour, vitreous humour and serum at day-7 were estimated biochemically. Fisher's Exact, Chi-Square and Mann-Whitney test were used to analyse the data. Results: There was no statistically significant difference in clinical inflammatory features (p > 0.05) between honey treated and the conventional treated group at different times of examination. Histopathological examination of the cornea showed the number of polymorphonuclear leucocytes was below 50 for both groups (mild grade). There was also no significant difference in the level of total antioxidant status as well as lipid peroxidation products in aqueous humour (p = 0.117, p = 0.382 respectively), vitreous humour (p = 0.917, p = 0.248 respectively) and serum (p = 0.917, p = 0.332 respectively) between honey treated and the conventional treated group. Conclusion: Tualang honey has almost the equal effects when compared with the conventional treatment in treating alkali injury on rabbit's eye. Future research with more number of rabbits and control group is warranted to explore the anti-inflammatory and antioxidant effects of Tualang honey.