OBJECTIVETo clarify the effect of histamine H4 receptor antagonist, JNJ 7777120, and histamine H1 receptor antagonist, Loratadine, on allergic rhinitis (AR) in rats and to study the role of histamine H4 receptor antagonist and histamine H1 receptor antagonist in the pathogenesis of allergic rhinitis and therapeutic value of their antagonist.

METHODSAR animal model were induced by ovalbumin (OVA) in the Wistar rats, which treated with histamine H4 receptor antagonist and (or) histamine H1 receptor antagonist. The allergic symptoms (sneezing and nasal rubbing), serum total IgE and the levels of cytokines in serum or nasal lavage fluid were measured, the diversity between two groups were observed. Statistical analysis was performed using a SPSS 13.0 software.

RESULTSCompared with AR group with no treatment, the inhibition of nasal symptoms (P < 0.01), a significant decrease in the levels of IgE, IL-4 in serum and Eotaxin in nasal lavage fluid (P < 0.01), a significant increase in the levels of IFN-γ in serum (P < 0.01) after treatment was found. Compared with group treated with Loratadine, inhibition of nasal symptoms (q value were 3.72, 4.16, P < 0.01), a significant increase in the levels of IgE and IL-4 in serum (q value were 8.01, 4.96, P < 0.05), a significant decrease in the levels of IFN-γ in serum (q = 3.18, P < 0.05) in group treated with JNJ 7777120 also, but no significant differences in the levels of Eotaxin in nasal lavage fluid (P > 0.05). Administration of JNJ 7777120 and Loratadine jointly, neither additive effect nor synergistic action were found (P > 0.05).

CONCLUSIONSHistamine H4 receptor is closely related with allergic rhinitis and is important in the pathogenesis of allergic rhinitis, the same as histamine H1 receptor. Histamine H4 receptor antagonist, JNJ 7777120, could relieve symptoms and inflammatory conditions in allergic rhinitis, the effect was weak compared with Loratadine. Neither additive effect nor synergistic action were found between them.