Acupuncture inhibited airway inflammation and group 2 innate lymphoid cells in the lung in an ovalbumin-induced murine asthma model.

ABSTRACT

BACKGROUND: Group 2 innate lymphoid cells (ILC2s) are known to serve important functions in the pathogenesis of allergic airway inflammation. Studies have shown that acupuncture has an anti-inflammatory effect in the airways. However, how acupuncture treatment affects innate immunity, especially with regard to the function of ILC2s in ovalbumin (OVA)-induced allergic airway inflammation, is poorly understood. METHODS: BALB/c mice were injected and subsequently challenged with OVA ± treated with manual acupuncture. At the end of the experimental course, lung function was assessed by measurement of airway resistance (RL) and lung dynamic compliance (Cdyn). Cytokine levels were detected by enzyme-linked immunosorbent assay (ELISA). ILC2 proportions in the lung were analyzed by flow cytometry. RESULTS: The results showed that airway inflammation and mucus secretion were significantly suppressed by acupuncture treatment. RL decreased while Cdyn increased after acupuncture treatment. There was an apparent decrease in the bronchoalveolar lavage fluid (BALF) concentrations of interleukin (IL)-5, IL-13, IL-9, IL-25 and IL-33 and an increase in soluble IL-33 receptor (sST2) levels compared with untreated asthmatic mice. Acupuncture also reduced the lin-CD45+KLRG1+ST2+ cell proportion in the lung. CONCLUSION: In conclusion, this study has demonstrated that acupuncture treatment alleviates allergic airway inflammation and inhibits pulmonary ILC2 influx and IL-5, IL-9 and IL-13 production. The inhibition of ILC2s by acupuncture may be associated with the IL-33/ST2-signaling pathway and IL-25 levels, thereby offering protection from the respiratory inflammation associated with asthma.