Immediate Effect of 3% Diquafosol Ophthalmic Solution on Tear MUC5AC Concentration and Corneal Wetting Ability in Normal and Experimental Keratoconjunctivitis Sicca Rat Models

Purpose: To evaluate the immediate effect of 3% diquafosol ophthalmic solution on tear MUC5AC concentration, periodic acid-Schiff (PAS)-positive goblet cells, and tear film stability in normal and keratoconjunctivitis sicca (KCS) rat models.Methods: Rats were divided into normal and KCS groups. 3% of diquafosol solution was instilled into the right eye and normal saline into the left eye in both groups. To determine the peak time of tear MUC5AC concentration, tears were collected after 3% diquafosol instillation every 5 min up to 20 min. The tear film stability and the numbers of PAS-positive goblet cells were compared in both models.Results: After diquafosol instillation, tear MUC5AC concentration increased steadily for 15 min, at which point the MUC5AC concentration reached its peak. In both normal and KCS groups, the MUC5AC concentration at 15 min was higher after instillation of 3% diquafosol solution (17.77 ± 2.09 ng/ml in the normal group, 9.65 ± 3.51 ng/ml in the KCS group) than that after saline instillation (13.74 ± 2.87 ng/ml in the normal group, 8.19 ± 3.99 ng/ml in the KCS group) (p = 0.018 for both). The corneal wetting ability was significantly longer after instillation of 3% diquafosol solution compared with that after instillation of normal saline in the normal group (p = 0.018). The percentage of PAS-positive goblet cells after the instillation of 3% diquafosol solution was significantly lower than that after instillation of normal saline in both models (p = 0.018 for both).Conclusions: Diquafosol ophthalmic solution was effective in stimulating mucin secretion in both normal and KCS rat models, and the peak time of tear MUC5AC concentration was 15 min after diquafosol instillation. The increased tear MUC5AC concentration was accompanied by improved tear film stability and a decreased percentage of PAS-positive goblet cells.