Publication Date
6-3-2024
Journal
Investigative Ophthalmology & Visual Science
DOI
10.1167/iovs.65.6.39
PMID
38935032
PMCID
PMC11216279
PubMedCentral® Posted Date
6-27-2024
PubMedCentral® Full Text Version
Post-print
Published Open-Access
yes
Keywords
Animals, Dry Eye Syndromes, Mice, Mice, Inbred C57BL, Disease Models, Animal, Goblet Cells, Interferon-gamma, Mucins, Interleukin-13, Conjunctiva, Enzyme-Linked Immunosorbent Assay, Female, Epithelium, Corneal, Real-Time Polymerase Chain Reaction, RNA, Messenger, Amino Acids, Diaminom, dry eye, ectoine, IFN-γ, IL-13, mucins, murine model
Abstract
PURPOSE: This study aimed to explore protective effects and potential mechanism of ectoine, a natural osmoprotectant, on ocular surface mucin production in dry eye disease.
METHODS: A dry eye model was established in C57BL/6 mice exposed to desiccating stress (DS) with untreated (UT) mice as controls. DS mice were topically treated with 2.0% ectoine or PBS vehicle. Corneal epithelial defects were assessed by Oregon Green Dextran (OGD) fluorescent staining. Conjunctival goblet cells, ocular mucins, and T help (Th) cytokines were evaluated by immunofluorescent staining or ELISA, and RT-qPCR.
RESULTS: Compared with UT mice, corneal epithelial defects were detected as strong punctate OGD fluorescent staining in DS mice with vehicle, whereas ectoine treatment largely reduced OGD staining to near-normal levels. Conjunctival goblet cell density and cell size decreased markedly in DS mice, but was significantly recovered by ectoine treatment. The protein production and mRNA expression of two gel-forming secreted MUC5AC and MUC2, and 4 transmembrane mucins, MUC1, MUC4, MUC16, and MUC15, largely decreased in DS mice, but was restored by ectoine. Furthermore, Th2 cytokine IL-13 was inhibited, whereas Th1 cytokine IFN-γ was stimulated at protein and mRNA levels in conjunctiva and draining cervical lymph nodes (CLNs) of DS mice, leading to decreased IL-13/IFN-γ ratio. Interestingly, 2.0% ectoine reversed their alternations and restored IL-13/IFN-γ balance.
CONCLUSIONS: Our findings demonstrate that topical ectoine significantly reduces corneal damage, and enhances goblet cell density and mucin production through restoring imbalanced IL-13/IFN-γ signaling in murine dry eye model. This suggests therapeutic potential of natural osmoprotectant ectoine for dry eye disease.