Abstract:Objective To investigate the effect of Th1/Th2/Th17 balance on development of experimental allergic conjunctivitis. Methods Forty Brown Norway rats were randomly divided into three groups: normal group, control group and experimental allergic conjunctivitis group (experimental group). Ovalbumin (OVA)-
induced allergic conjunctivitis models were established. The eyes including eyelids and conjunctivae were harvested for histological analysis, and infiltrating eosinophils in fornical conjunctivae were counted. The serum levels of IgE, IgG1 and IgG2a and the concentrations of IL-17, IL-4, IL-6, IL-10 and IFN-γ in spleen culture supernatant were measured by ELISA. The Th17 cells in peripheral blood and spleen tissue were detected using flow cytometry. Results The experimental group had significantly higher number of conjunctival eosinophils than the normal and control groups (P < 0.01). The experimental group had significantly higher serum IgE and IgG1 levels and significantly lower serum IgG2a level than the normal and control groups (P < 0.01). The concentrations of IL-17, IL-4, IL-6 and IL-10 in spleen culture supernatant were significantly higher but the IFN-γ level was significantly lower in the experimental group than in the normal and control groups (P < 0.01). The Th17 cells in the peripheral blood and spleen tissue of the experimental group were significantly more than those of the normal and control groups (P < 0.01). Conclusions Th1/Th2/Th17 imbalance might play an important role in the development of experimental allergic conjunctivitis. To modulate the unbalanced Th1/Th2/Th17 reaction may contribute to treatment of allergic conjunctivitis.