OBJECTIVE To investigate the anti-inflammatory effect of electroacupuncture in mice with chronic obstructive pulmonary disease (COPD) and its underlying mechanisms.

METHODS Forty C57BL/6 mice were randomly divided into normal group, model group, electroacupuncture (EA) group, vagotomy group, and vagotomy+EA group, with 8 mice in each group. Except for the normal group, all groups were exposed to cigarette smoke for 12 weeks to establish a COPD model. After model establishment, the vagotomy group and the vagotomy+EA group underwent left cervical vagotomy before EA. EA treatment was performed at the Feishu (BL13) and Zusanli (ST36) acupoints once daily for 20 minutes for a total of 14 days. After EA, the pulmonary ventilation function of the mice was detected by a pulmonary function analysis system; lung tissue pathology was observed by HE staining; the levels of interleukin (IL)-6, tumor necrosis factor-α (TNF-α), IL-10, and transforming growth factor-β (TGF-β) in lung tissue were detected by ELISA; the expression of CD86 and CD206 proteins in lung tissue was detected by Western blot; the distribution of F4/80⁺CD86⁺ (M1 type) and F4/80⁺CD206⁺ (M2 type) cells in lung tissue was determined by flow cytometry; the expression of CD86 and CD206 in lung tissue was observed by immunofluorescence.

RESULTS Compared with the normal group, the model group showed significantly decreased lung function (P < 0.01), obvious lung pathological damage, increased M1 proportion, IL-6, TNF-α, CD86 content and expression (P < 0.05, P < 0.01), and decreased M2 proportion, IL-10, TGF-β, CD206 content and expression (P < 0.01). Compared with the model group, the EA group showed varying degrees of improvement in lung function and pathology; the M1 proportion, IL-6, TNF-α, and CD86 were reduced (P < 0.05, P < 0.01), while the M2 proportion, IL-10, TGF-β, and CD206 were increased (P < 0.05, P < 0.01). The vagotomy group showed worsened lung function and pathology, increased IL-6, TNF-α, and CD86 content and expression (P < 0.05, P < 0.01), and decreased IL-10, TGF-β, and CD206 content and expression (P < 0.05, P < 0.01). Compared with the EA group, the vagotomy+EA group showed increased M1 proportion, IL-6, TNF-α, and CD86 content and expression (P < 0.01), and decreased M2 proportion, IL-10, TGF-β, and CD206 content and expression (P < 0.05, P < 0.01).

CONCLUSION EA at Feishu(BL13) and Zusanli(ST36) acupoints can improve lung function and pulmonary inflammation in COPD mice, promoting the polarization of alveolar macrophages from M1 to M2, which is mediated by the vagus nerve.