Therapeutic effects of gyokuheifusan on NC/Nga mouse model of allergic dermatitis

Gyokuheifusan (GHS) is a traditional Chinese medicine (TCM) formula used to treat various allergic diseases; however, there is little information about its clinical efficacy or mechanism of action. We previously showed that GHS down-regulates over-production of IgE and interleukin (IL)-4 in a mouse model of ovalbumin (OVA)-induced asthma, a major Th2-dominant disease. Here, we investigated the effect of GHS in an NC/Nga mouse model of atopic dermatitis (AD) induced by mite antigen. NC/Nga mice were immunized with an intradermal injection of mite antigen extract twice a week from 6 to 12 weeks of age. GHS (3.0 g/kg) was orally administered daily to the GHS-treated group for 6 weeks, and dermatitis score and total serum IgE level were measured sequentially. Spleen was harvested at 13 weeks of age, and the levels of cytokines released from splenocytes (interferon (IFN)-γ, IL-4 and IL-5) and IgG1/IgG2a levels in sera were measured by ELISA. Mice treated with GHS showed milder dermatitis than the disease-control group and the increase of total serum IgE level tended to be suppressed by GHS. In addition, GHS treatment suppressed the production of IL-4 and IgG1, though it did not affect the production of IFN-γ and IgG2a; i.e., GHS normalized the Th1/Th2 balance. These results suggest that GHS inhibits the development and reduces the severity of AD, at least in this model.