Changes in ocular surface and subbasal nerve plexus in an autoimmune dry eye mouse model

Abstract

Purpose : Recent evidence from clinical studies highlights the significant role of corneal nerves in the pathophysiology of dry eye disease. Here, we aim to examine changes in the ocular surface and neural integrity using the NOD.B10-H2^b (NOD) mouse model of ocular Sjögren's syndrome.

Methods : NOD male mouse at 7, 15, and 21 weeks of age were examined in this study. Ocular surface alterations were evaluated with lissamine green staining, and corneal whole-mount staining using anti-β-tubulin III antibody was performed to assess corneal nerves. Corneal nerve morphology was evaluated with confocal microscopy. The number and length of the subbasal nerve plexus were assessed using semi-automated software ImageJ and its plug-in NeuronJ. The resolution of each frame was 300 x 300 pixels over an area of 85.14 x 85.14 um, and 8 bits of data were used.

Results : The average National Eye Institute (NEI) corneal staining score of 7-, 15-, and 21-weeks NOD mouse was 7.13 ± 2.59, 10.7 ± 1.73, and 11.7 ± 1.51, respectively, showing a statistically significant increase at 15 and 21 weeks compared to 7 weeks (all p < 0.01). In both the central and peripheral corneal nerves, there was a significant decrease in nerve count and length at 21 weeks compared to 7 and 15 weeks (all p < 0.001). In the central corneal nerve, there was no significant difference in nerve count (50 ± 14.0 count/frame, 41 ± 14.0 count/frame) and length (4416 ± 803 pixels/frame, 3873 ± 1170 pixels/frame) at 7 and 15 weeks. However, a statistically significant decrease in both nerve count (52 ± 9.8 count/frame, 35 ± 11.0 count/frame) and length (5240 ± 780 pixels/frame, 3565 ± 840 pixels/frame) was observed in the peripheral cornea nerve (all p < 0.001).

Conclusions : Changes in the ocular surface appear to occur between 7 and 15 weeks in NOD mouse. Morphological changes in the cornea nerves are thought to start from the periphery of the cornea in the same period and progress toward the center. These changes are observed throughout the entire cornea around the 21 weeks. These suggests a role for neurosensory abnormalities in the pathophysiology of autoimmune dry eye.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.