Abstract
Purpose :
Recently studies performed on TRP(transient receptor potential, TRP) channel for thermal and mechanical stimulation demonstrate that it affects inflammatory immune responses as well as pain sensation. In this study, we investigated the immunological role of TRPA1 and TRPV1 in allergic conjunctivitis murine model.
Methods :
7-8 week-old BALB/c mice were sensitized via intraperitoneal injection once with Ovalbumin (OVA) and aluminum hydroxide. Mice were rested for 2 weeks and then challenged by instillation of OVA eyedrops once daily for 13 days. The expression of TRPA1 and TRPV1 was performed by western blot and immunohistochemistry in the allergic conjunctivitis model. Mice that OVA sensitized and by intraperitoneal injection once with aluminum hydroxide were rested for 2 weeks and then challenged by instillation of OVA eyedrops once daily for 13 days. HC-030031 (TRPA1 antagonist, HC) and Capsazepine (TRPV1 antagonist, Cap) eyedrops were administered 20min before OVA challenge once daily. Clinical signs were measured and we evaluated the infiltration of eosinophils and mast cells into conjunctiva with flow cytometry, and serum levels of OVA specific IgE production and Th2 cytokines in vitro stimulation of T cell in drainage lymph nodes (LN).
Results :
In allergic conjunctivitis, TRPA1 expression was increased only in lymph node, but TRPV1 expression was increased in both conjunctiva and lymph node and TRPV1 was expressed mainly at T cell area. Cap treated mice showed less allergic conjunctivitis indicated by clinical signs and decreased production of serum OVA specific IgE. In addition, Cap treatment led to decreased infiltrations of CD45 positive immune cells, eosinophils and mast cells into conjunctiva, compare to only vehicle treated (control) mice. Cap administration suppressed Th2 cytokine production in vitro T cells assay.
Conclusions :
Taken together, these results suggest that Capsazepine could suppress the Th2 response in drainage LNs and conjunctival eosinophil infiltration, as the therapeutic potential of topical Capsazepine for allergic conjunctivitis.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.