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.