Methods: Dry eye was induced in C57BL/6 mice by a subcutaneous scopolamine (0.5 mg/0.2 mL) injection and a dry air draft during a 10-day period. The mice were divided into 3 groups according to treatment regimens: dry eye control (group 1), isotonic 0.3% HA (group 2), hypotonic 0.3% HA (group 3). Corneal staining score was measured 5 and 10 days after dry eye induction. Concentration of tumor necrosis factor (TNF)-α and interleukin (IL)-1β was measured in the conjunctiva, cornea, and lacrimal gland, 10 days after dry eye induction. In addition, conjunctival goblet cell density was measured in each group.

Results: At day 5, corneal staining score was significantly lower in group 3, compared with group 1 (p < 0.01). Both treatment groups showed significantly lower corneal staining score, compared with group 1, 10 days after dry eye induction (p < 0.05). Moreover, corneal staining score was significantly lower in group 3, compared with group 2, at day 10. A significant decrease in the levels of TNF-α was observed in group 2 and 3 (p < 0.05), and concentration of IL-1β showed significant decrease in group 3, compared with group 1 (p = 0.02). There were no significant differences in the cytokine levels of cornea and lacrimal gland between groups. Conjunctival goblet cell density was significantly increased in the treatment groups, and group 3 showed significantly higher conjunctival goblet cell density than group 2 (p < 0.01).

Conclusion: Topical application of hypotonic 0.3% HA can improve ocular surface integrity, and decrease inflammatory cytokines, compared with isotonic 0.3% HA. These results suggest that topical hypotonic 0.3% HA eye drops may be useful for the treatment of dry eye disease.

Ann Optom Contact Lens 2015;14(3):145-149