Purpose: The purpose of this study was to investigate the effectiveness of tumor necrosis factor (TNF)-α blocker for treatment of dry eye (DE)-induced inflammation and determine a more effective method to suppress lacrimal gland inflammation. Efficacy of topical versus systemic administration of TNF-α blockers was determined using a murine dry eye (DE) model.
Methods: The TNF-α blocker HL036 was developed by modification of the TNF receptor I. Protein purity, binding affinity, and clearance of TNF-α was compared with etanercept. Using DE-induced C57BL/6 mice, corneal erosion and goblet cell counts were measured after subcutaneous or topical treatment with etanercept or HL036. Inflammatory cytokines in cornea and lacrimal glands were determined by quantitative RT-PCR and ELISA.
Results: HL036 showed TNF-α binding affinity comparable to etanercept, as measured by surface plasmon resonance. HL036 concentration was significantly higher in cornea and anterior segment than etanercept and effectively eliminated TNF-α on ocular surfaces. Etanercept was preferentially concentrated in the posterior segment. Corneal erosion and goblet cell counts were improved only with topically applied etanercept and HL036. Ocular surface IFN-γ, IL-6, and IL-21 were significantly decreased by topical HL036. DE-induced lacrimal gland IFN-γ and IL-6 expression was effectively suppressed by topical etanercept and HL036.
Conclusions: Topical TNF-α blockers effectively suppressed lacrimal gland and corneal inflammation by suppressing IFN-γ, IL-21, and IL-6. Differences in TNF-α affinity, clearance, and local concentration of blockers may account for the anti-inflammatory effects in different ocular regions.
Keywords: cytokines; dry eye; lacrimal gland; tumor necrosis factor‐α.