Abstract
Purpose :
Dry eye disease (DED) is characterized by loss of tear-film stability. Currently, desiccation stress (DS) is the predominant means for inducing DED in mice, however its effect on limbal epithelial stem cells (LESCs) has been overlooked. This study aimed to establish a DS model of DED using our in-house system to investigate the impact on the ocular surface including LESCs.
Methods :
A mouse transporter unit was customized to generate a dehumidified environment in an isolated room. C57BL/6j mice were exposed to mild DS or remained untreated (UT) in our vivarium for 10 consecutive days (n=28/group). Clinical assessments included phenol red tear-thread, fluorescein staining and optical coherence tomography (OCT). Histopathology and immunofluorescence was used to evaluate tissue architecture, goblet cell (GC) status, lacrimal gland (LG) inflammation and ocular surface phenotype. Whole flat-mounted corneas were immunostained for K14, imaged by confocal microscopy and analyzed to investigate the effect of DS on LESCs.
Results :
Modifications made to the animal transporter unit resulted in decreased relative humidity (RH) in cages (43.5 ± 4.79%) compared to those in the vivarium (53.9 ± 1.8%, p=0.0243). Under these conditions, tear production was suppressed whilst corneal permeability and corneal irregularity significantly increased. H&E staining indicated that basal corneal epithelia were stressed and increased desquamation. However, no major change in corneal thickness was detected using OCT. DS-exposed mice had reduced GC density (41.0 ± 5.10 GC/mm vs 46.9 ± 3.88 GC/mm, p=0.0482) and their LGs had elevated CD4+ T-cells compared to controls. DS also elicited K14+ epithelial cell displacement, as indicated by increased normalized fluorescence signal distanced 50-100 µm radially inwards from the limbus [0.63 ± 0.053% (DS) vs 0.54 ± 0.060% (UT), p=0.0317].
Conclusions :
Mild DS applied to C57BL/6 mice using a customized system generated features of DED. Following DS, ocular surface epithelial cell health decreased and LESCs appeared stressed. This suggests that downstream effects of DS on corneal homeostasis are present. The method used to induce DED in this study enables a chronic model to be developed which more closely resembles the clinical situation.
This is a 2021 ARVO Annual Meeting abstract.