Outline of the experimental protocol and electroacupuncture (EA) stimulation.

<p>(A) Mice received EA or sham EA for 30 min after subcutaneous or intrathecal administration of recombinant IL-33 (rIL-33) or the ST2 antibody, and then formalin was immediately administered via intra-plantar injection. Paw lifting and licking duration were observed for 45 min. After the behavior test, the spinal cord was harvested. (B) Schematic diagram showing the two acupoints applied to the formalin mice. Acupuncture was ipsilaterally applied at two specific acupoints, Zusanli (ST 36) and Yanglingquan (GB 34), throughout the experiments.