Evaluation of Ocular Surface Changes in a Rabbit Dry Eye Model Using a Modified Impression Cytology Technique

Abstract

Purpose: To evaluate the ocular surface changes in a rabbit dry eye model by using a modified impression cytology technique. Methods: Nitrocellulose filter paper with a pore diameter of 0.45 μ m was used to collect the specimens from 12 rabbits that were injected with atropine every day for 3 days. Filter papers were kept in distilled water overnight and then dried to increase cell pickup. Samples were stained with periodic acid–Schiff. The mean temporal and superior bulbar conjunctival goblet cell densities were counted. The data were compared with transmission (ocular surface) and scanning electron microscopic (filter paper) examination of the ocular surface. Results: In the acute stage of atropine injection, there was not a major change in the goblet cell count. Although the goblet cell distribution was variable over the ocular surface, the average cell density was 55.4 ± 22 in the superior quadrant and 69.2 ± 9 in the temporal quadrant. In the 3-day atropine-injection group, there was a marked decrease in goblet cells, and there was mucin accumulation rather than accumulation of the goblet cells. No morphologic differences could be observed with scanning electron microscopy between the regular nitrocellulose filter paper and the paper kept in distilled water. Conclusions: The findings indicate that keeping the filter paper in distilled water and then drying it improves cell pickup and ocular surface evaluation in rabbits.

KEYWORDS:

• dry eye
• impression cytology
• ocular goblet cells
• rabbit