Purpose: To determine the immunologic functions of TRPA1 or TRPV1 in allergic conjunctivitis (AC).
Methods: Mice were sensitized with ovalbumin (OVA), after which TRPA1 antagonist or TRPV1 antagonist was administered before topical OVA challenge. Expression of TRPV1 or TRPA1 in AC was examined by western blotting and multicolor immunofluorescence. Clinical signs, OVA-specific IgE, infiltration of inflammatory cells into conjunctivae (CJs), and Th2 cytokine in draining lymph nodes (LNs) were evaluated by microscopy, flow cytometry, and ELISA.
Results: TRPV1 expression was increased in CJs and LNs from AC mice, but TRPA1 expression was only increased in LNs. TRPV1 antagonist but not TRPA1 antagonist attenuated the clinical signs of AC and OVA-specific IgE in sera. TRPV1 antagonist furthermore inhibited the infiltration of inflammatory cells into CJ and the production of Th2 cytokines in LNs.
Conclusion: TRPV1 antagonist but not TRPA1 antagonist may ameliorate AC by suppressing the Th2 response in LNs.
Keywords: Allergic conjunctivitis; TRPA1; TRPV1; Th2 cytokines; inflammatory cells.