SPECIFIC CB2 RECEPTOR AGONIST SUPPRESSES THE MURINE MODEL OF EXPERIMENTAL AUTOIMMUNE UVEITIS

Abstract

Abstract: : Purpose:To investigate whether the specific cannabinoid CB2 receptor agonist JWH 133 could suppress inflammation and its mechanisms. Methods:A murine model of experiment autoimmune uveoretinitis (EAU) was used in the study. EAU was elicited by immunizing B10.RIII mice subcutaneously with 100 µg interphotoreceptor retinol binding protein (IRBP) (161–180) emulsified with an equal volume of Freund’s complete adjuvant (CFA). JWH 133 was injected intraperitoneally (ip) at various doses (0.15mg/kg to 15mg/kg once a day) at different time post–immunization (p.i). Inflammation of the eyes was scored clinically from day 9 p.i. to day 15 p.i. and histologically at day 15 p.i.. Activation and proliferation of draining lymph node cells and spleen cells were analysed in both EAU control group and JWH treated group. Analysis of CB2 receptor expression was performed by immunohistochemistry on eyes with EAU. Results:JWH133 administration suppressed the onset and progression of EAU. Dose–dependant suppression was demonstrated with complete inhibition of EAU at 15mg/kg ip. Administration of JWH 133 from day 0 to day 7 p.i. alone or day 7 to day 15 p.i. alone were both shown to suppressed EAU. Ex vivo and in vitro analysis of draining lymphnode and spleen cells showed that JWH 133 suppressed IRBP–specific as well as non specific Con A induced activation and proliferation. Confocal fluorescence microscopy revealed that retinal infiltrated cells predominantly T cells and macrophages were positive for CB2 receptor. Conclusions:JWH 133 is effective in suppressing murine EAU. It is able to block antigen presentation as well as efferent phases of EAU with resultant prevention of tissue damage in the retina.

Keywords: immunomodulation/immunoregulation • immunohistochemistry • flow cytometry