Topical application of mizoribine suppresses CD4+ T-cell-mediated pathogenesis in murine dry eye

Abstract

PURPOSE. We investigate the effect of topical application of mizoribine (MZR) eye drops on CD4+ T-cell-mediated immunity and epithelial damage in ocular surface of dry eye disease (DED). METHODS. Topical application of MZR or vehicle eye drops was performed in mice subjected to desiccating stress (DS). The phenol red cotton test was used to measure tear production, and Oregon-green-dextran (OGD) staining was performed to assess corneal epithelial barrier function. PAS staining was used to quantify conjunctival goblet cells. Immunofluorescent staining and quantitative (q) RT-PCR were used to assess the expression of matrix metalloproteinase (MMP)-9 in corneal epithelium. qRT-PCR and ELISA were used to assess the production of TNF-α and IL-1β in conjunctiva. Apoptosis in ocular surface was assessed by TUNEL and activation of caspase-8. CD4+ T-cell-mediated immunity was evaluated by CD4 immunohistochemistry and production of T helper cytokines, including IFN-γ, IL-13, and IL-17A in conjunctiva. RESULTS. Compared to vehicle control mice, topical MZR-treated mice showed increased tear production, decreased goblet cell loss, and improved corneal barrier function. Topical application of MZR suppressed the expression of MMP-9 in corneal epithelium and apoptosis in ocular surface, while it had no obvious effect on production of TNF-α and IL-1β in conjunctiva. Topical application of MZR decreased CD4+ T cells infiltration, with decreased production of IFN-γ and IL-17A, and increased production of IL-13 in conjunctiva. CONCLUSIONS. Topical application of MZR could alleviate epithelial damage and CD4+ T-cell-mediated immunity in ocular surface of DED.