Topical tacrolimus for the management of acute allergic conjunctivitis in a mouse model

Acute allergic conjunctivitis is a constantly challenging condition that often requires steroids for effective management. Alternative treatment options are needed due to the potential side effects of steroids. Tacrolimus has been used for vernal/atopic conjunctivitis. The aim of our study was to investigate the therapeutic effect of topical administration of 0.03 % tacrolimus (eye drops or ointment) in comparison to 0.1 % dexamethasone in a mouse model of acute allergic conjunctivitis.

BALB/c mice were sensitized by an intraperitoneal injection of 10 μg/0.2 ml ovalbumin (OVA) absorbed on ALUM (2.0 mg) on days 1 and 8. They were challenged by topical instillation of 2 μl of 15 % OVA (absorbed in 10 % glycerol) twice daily, on days 15-21. Treatment was administered twice daily on days 17-21. Mice were randomly assigned topical treatment groups: Group 1, 0.1 % dexamethasone drops; Group 2, 0.03 % tacrolimus drops; Group 3, 0.03 % tacrolimus ointment; Group 4 PBS drops (control). On day 22 all mice underwent clinical evaluation, blood sampling for IgE levels, and conjunctivas were removed for eosinophil counting.

IgE and OVA-specific IgE levels were similar among all groups, demonstrating induction of allergic reaction in all mice. Significantly lower clinical scores were found among all treated groups as compared to controls (P < 0.001), while no significant difference was found among the three treatment groups (P > 0.05). Conjunctival eosinophil counts were significantly lower in Group 1 (P < 0.05) as compared to the other groups.

The clinical efficacy of topical 0.03 % tacrolimus was similar to 0.1 % dexamethasone for acute allergic conjunctivitis.