Comparison of 0.3% Hypotonic and Isotonic Sodium Hyaluronate Eye Drops in the Treatment of Experimental Dry Eye

ABSTRACT

Purpose: To compare the efficacy of 0.3% hypotonic and isotonic sodium hyaluronate (SH) eye drops in the treatment of experimental dry eye.

Methods: Experimental dry eye was established in female C57BL/6 mice by subcutaneous scopolamine injection and an air draft. The mice were divided into three groups (n = 15): control, preservative-free 0.3% isotonic SH, and preservative-free 0.3% hypotonic SH. The tear volume, tear film break-up time, and corneal fluorescein staining scores were measured 5 and 10 days after treatment. After conjunctival tissues were excised at 10 days, the levels of interleukin (IL)-6, IL-17, interferon (IFN)-γ, and IFN-γ inducible protein-10 were determined using the multiplex immunobead assay. In addition, PAS staining and flow cytometry were performed to evaluate the counts of conjunctival goblet cells and CD4+ IFN-γ+ T cells.

Results: Mice treated with 0.3% hypotonic SH showed a significant decrease in corneal staining scores (P = 0.04) and the levels of IL-6 (16.7 ± 1.4 pg/mL, P = 0.02) and IFN-γ (46.5 ± 11.5 pg/mL, P = 0.02) compared to mice treated with 0.3% isotonic SH (IL-6; 32.5 ± 8.8 pg/mL, IFN-γ; 92.0 ± 16.0 pg/mL) at day 10. Although no significant difference in CD4+ IFN-γ+ T cell numbers was observed, goblet cell counts were higher in the hyopotonic SH group than in the isotonic SH group (P = 0.02).

Conclusions: When compared to 0.3% isotonic SH eye drops, 0.3% hypotonic SH eye drops can be more effective by improving corneal staining scores, decreasing inflammatory molecules, and increasing goblet cell counts for experimental dry eye. These data suggest that hypotonic artificial tears may be useful as an adjunctive treatment for inflammatory dry eye.

KEYWORDS:

• Dry eye
• eye drops
• hypotonic
• isotonic
• sodium hyaluronate

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Funding

The study was partially supported by the Chong Kun Dang Pharmaceutical Corp. and Forest Science & Technology Projects (Project No. S121313L50100) provided by Korea Forest Service. In addition, this research was financially supported by the Ministry of Trade, Industry, and Energy (MOTIE), Korea, under the “Regional Specialized Industry Development Program”(reference number R0005197) supervised by the Korea Institute for Advancement of Technology (KIAT). The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.

Additional information

Funding

The study was partially supported by the Chong Kun Dang Pharmaceutical Corp. and Forest Science & Technology Projects (Project No. S121313L50100) provided by Korea Forest Service. In addition, this research was financially supported by the Ministry of Trade, Industry, and Energy (MOTIE), Korea, under the “Regional Specialized Industry Development Program”(reference number R0005197) supervised by the Korea Institute for Advancement of Technology (KIAT). The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.