Olopatadine Exerts Multifaceted Protective Effects in an Ovalbumin-Induced Allergic Eye Disease Mouse Model

Allergic eye disease (AED), including allergic conjunctivitis, is a prevalent immune-mediated disorder of the ocular surface characterized by itching, redness, tearing, and ocular discomfort. Although olopatadine (OLO) is widely used as an antihistamine and mast cell stabilizer, its broader effects on immune-mediated inflammation, neuropeptide-associated responses, and epithelial-mucosal changes in AED remain incompletely understood. This study investigated the multifaceted effects of OLO in an ovalbumin (OVA)-induced AED mouse model. AED was induced in BALB/c mice by OVA sensitization and topical challenge, followed by OLO treatment during the challenge period. Clinical severity, scratching behavior, serum IgE, inflammatory cell infiltration (PMNs), mast cell degranulation, cytokine expression (IL-4, IL-5, IL-6, TNF-α, and IL-1β), macrophage infiltration (F4/80), iNOS expression, TRPV1, SP, and CGRP expression, ZO-1 expression, goblet cell density, mucin expression (MUC5AC), dysregulated cell proliferation (Ki67), and apoptotic cell death (TUNEL) were assessed. OVA challenge induced marked allergic responses, including elevated clinical scores, increased scratching behavior, elevated serum IgE, mast cell degranulation, inflammatory cell infiltration, and upregulation of Th2- and pro-inflammatory cytokines. In addition, OLO reduced TRPV1, SP, and CGRP expression, preserved ZO-1 expression and goblet cell density, and reduced excessive epithelial cell proliferation. Notably, OLO demonstrated multifaceted protective effects in AED, providing preclinical insights into its effects in experimental AED while acknowledging its established clinical use in humans.