Tear film hyperosmolarity breaks down the ocular surface?s immune tolerance - a role in initiating dry eye?

GUZMÁN MAURICIO; KEITELMAN IRENE; SABBIONE FLORENCIA; TREVANI ANALÍA SILVINA; GIORDANO MIRTA NILDA; GALLETTI JEREMÍAS GASTÓN

Denver

Congreso; ARVO 2015 Annual Meeting; 2015

ARVO

Purpose: Tear film hyperosmolarity is commonly observed in dry eye, but its exact role in the pathogenesis of this ocular surface disorder is unknown. As a localized form of autoimmune disease, dry eye involves disruption of the ocular surface?s immune homeostasis by still uncharacterized stimuli. The purpose of this work was to evaluate whether hyperosmolar stress could affect conjunctival immune tolerance in mice.Methods: 8-to-12 week-old female Balb/c mice were instilled isoosmolar (0.3 Osm) or hyperosmolar (3 Osm) saline on both eyes 3 times daily for 5 days. Ovalbumin (OVA) was also instilled or OVA-pulsed dendritic cells (DCs) were subconjunctivally injected at different time points. Induced T cell responses were measured after subcutaneous immunization with OVA by the delayed-type hypersensitivity (DTH) assay. In addition, T cells in draining lymph nodes (day 5) were evaluated by flow cytometry. Supernatants from Pam212 epithelial cells exposed to iso- or hyperosmolar medium were assayed for cytokines or in a phagocytosis assay with the Raw 264.7 macrophage cell line.Results: Compared to non-instilled immunized mice, OVA-instilled mice developed reduced DTH responses (i.e. were tolerized), as did their OVA+0.3Osm saline-instilled cage mates (p