Revealing the clinical effect and biological mechanism of acupuncture in COPD: A review

Chronic obstructive pulmonary disease (COPD) is one of the leading causes of mortality worldwide, characterized by irreversible airflow limitation and chronic airway inflammation. This systematic review analyzed 45 studies published between 2012 and 2023, including 26 clinical trials and 19 basic mechanism studies, to evaluate the clinical efficacy and biological mechanisms of acupuncture in the treatment of COPD.

The clinical results demonstrate that acupuncture offers significant benefits for patients with COPD. Treatment improves symptoms such as exertional dyspnea, cough, and sputum production, and increases exercise tolerance through improved respiratory muscle and diaphragm function. Acupuncture has also been shown to reduce small airway obstruction and promote bronchodilation through increased levels of β-endorphins. In addition, treatment contributes to improvement in patients' quality of life, reducing anxiety, improving nutritional status, and decreasing alterations in blood viscosity.

From an immunological standpoint, acupuncture has been shown to regulate T-cell function, increasing the proportion of CD4+ lymphocytes and improving the TH/CTL balance. Treatment also improves erythrocyte immune function, increasing immune-promoting factors and reducing inhibitory factors, which results in lower airway resistance and improved overall immune function.

The anti-inflammatory mechanisms constitute the core of the therapeutic effects of acupuncture in COPD. The technique inhibits M1 macrophage activity, reduces neutrophil infiltration, and decreases the production of inflammatory factors by type II alveolar epithelial cells. Acupuncture also inhibits mucus hypersecretion by airway epithelial cells, controlling the progression of chronic inflammation and slowing the destruction of tissue structures.

The neurological mechanisms involve multiple pathways. The cholinergic-vagal anti-inflammatory pathway operates through regulation of α7 nicotinic acetylcholine receptors, while the vagal-adrenomedullary-dopamine pathway raises dopamine levels to exert systemic anti-inflammatory effects. The vagal-dual pulmonary sensory nerve fiber pathway regulates pulmonary neuroendocrine cells, and the central nervous system-hypothalamus-orexin pathway controls pulmonary inflammation through neuropeptide modulation.

From an endocrine standpoint, acupuncture can increase endogenous cortisol levels by modulating the hypothalamic-pituitary-adrenal axis, thereby improving the antioxidant capacity of the airways and reducing inflammation. This hormonal regulation contributes significantly to the observed therapeutic effects.

Analysis of the most frequently used acupuncture points revealed that EX-B1 (Dingchuan), BL-13 (Feishu), and ST-36 (Zusanli) are the most commonly employed, both in clinical studies and in basic research. Treatment parameters vary, with manual acupuncture being more common clinically (15-50 minutes) and electroacupuncture predominating in mechanistic studies (20-30 minutes, 1-5 mA).

Although the results are promising, important limitations must be considered. Heterogeneity in intervention methods, stimulation parameters, and evaluation criteria may influence the comparability of studies. In addition, issues related to controlled study design, including blinding and randomization methods, warrant attention in future research.

In conclusion, this review provides robust evidence that acupuncture represents an effective and safe complementary therapy for the treatment of COPD. The multiple mechanisms of action identified — anti-inflammatory, neurological, endocrine, and immunological — provide a solid scientific basis for its clinical application, suggesting that inhibition of the chronic inflammatory response is the key mechanism through which acupuncture exerts its therapeutic effects in COPD.