Electro-Acupuncture at Zusanli Acupoint (ST36) Suppresses Inflammation in Allergic Contact Dermatitis Via Triggering Local IL-10 Production and Inhibiting p38 MAPK Activation

Abstract

Acupuncture has shown beneficial effect in the treatment of multiple dermatologic conditions including dermatitis, pruritus, urticaria, and hyperhidrosis; however, the detailed mechanisms are still kept unclear. This study aimed to investigate if electro-acupuncture (EA) treatment prevents 2,4-dinitrofluorobenzene (DNFB)-induced allergic contact dermatitis (ACD) in rats and explore its underlying mechanisms. ACD was induced by sensitizing and challenging with DNFB topically. Rats were treated daily following bilateral subcutaneous stimulation of EA at Zusanli acupoint (ST36) for 1 week. Ear swelling and serum IgE levels were measured. The ear biopsies were obtained for histology. Inflammatory cytokines on the dermatological ear and local acupoint tissue were assayed. Spleen lymphocytes and the homogenized supernatant of local acupuncture area were used to co-culture for flow cytology and immune analysis, respectively. EA treatment at ST36 notably inhibited ear swelling and inflammatory cell infiltration on DNFB-induced ACD. EA also decreased serum IgE concentrations and alleviated the production of inflammatory cytokines in dermatological ear. Additionally, EA treatment attenuated the percentage of CD4⁺IFN-γ⁺ and CD4⁺IL-4⁺ T cells associated with ACD. Interestingly, secretion of interleukin (IL)-10 in the local acupoint tissue following EA stimulation was increased and showed suppressive function when co-cultured with the spleen lymphocytes from DNFB group. Lastly, EA treatment demonstrably suppressed p38 MAPK activation in DNFB-treated rats. Our findings suggest that EA treatment at ST36 may ameliorate inflammation associated with DNFB-induced ACD via triggering local IL-10 production and inhibiting p38 MAPK activation, which provide an alternative and promising therapy for ACD.

Keywords: IL-10; Zusanli; allergic contact dermatitis; electro-acupuncture; inflammation; p38 MAPK.