Catgut Implantation at Acupoint Reduces Immune Reaction in a Rat Model of Allergic Rhinitis

Allergic rhinitis (AR), an IgE-mediated response, is characterized by a Th2-type immunological pattern together with mast cells activation. Acupuncture, with the use of implanted catgut, is a traditional therapy that has been widely applied for the treatment of AR. However, the exact mechanism of the immunomodulatory effects of catgut implantation at acupoint (CIAA) remains unclear, in part due to the lack of a suitable laboratory animal model. We developed and optimized a rat model of ovalbumin- (OVA-) induced allergic inflammation, characterized by increased IL-4, sIgE, and SP and reciprocal decrease of IFN-γ. In the present study, we have further used this model to address the immunomodulatory effects of CIAA stimulation at Yingxiang (LI20) and Zusanli (ST36) acupoints and to elucidate the mechanisms involved in the regulation of SP, sIgE, IL-4, IFN-γ, TLR2, and TLR4. After AR model was established via OVA challenge, the rats were randomized as follows: control, model, sham-operated, 1-week CIAA (C1), 2-week CIAA (C2), and Budesonide nasal spray. The C1 and C2 groups were subjected to the bilateral acupoint Yingxiang (LI20) and Zusanli (ST36), respectively. Multiple analyses and quantifications were performed, which revealed that due to the persistent stimulus to acupoints by embedding catgut, the C2 group improved AR symptoms, compared to the C1 group. We conclude that CIAA at the Yingxiang (LI20) and Zusanli (ST36) acupoints effectively reduces allergic symptoms and inflammatory parameters in the rat model of AR. Thus, CIAA treatment is potentially an alternative therapeutic modality in AR.