Regulation of the IL-33/ST2 Pathway Contributes to the Anti-Inflammatory Effect of Acupuncture in the Ovalbumin-Induced Murine Asthma Model

Abstract

Background Bronchial asthma is a chronic airway inflammatory disease which has three main pathological features: airway hyperresponsiveness (AHR), airway remodelling, and chronic inflammation. Acupuncture is known to be an effective integrative medical therapy that has been used in the treatment of several chronic diseases, including bronchial asthma. The aim of the current study was to evaluate the effects of acupuncture on inflammation and regulation of the IL-33/ST2 pathway in a mouse model of asthma. Methods The murine asthma model was established by both injection and inhalation of ovalbumin (OVA). Within 24 hours of the last OVA challenge, lung function was assessed by measurement of the airway resistance (RL) and lung dynamic compliance (Cdyn). Pulmonary tissues were collected for the detection of pathological changes and mucus secretion. Serum levels of tumour necrosis factor α (TNF-α), interleukin (IL)-1β, IL-33 and sST2 (secreted ST2) were detected by ELISA. Th17 cell proportions and counts in bronchoalveolar lavage fluid (BALF) were analysed by flow cytometry. Results The results showed that AHR, chronic 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 serum concentrations of certain pro-inflammatory cytokines, such as TNF-α, IL-1β and IL-33, and an increase in sST2 level compared with untreated asthmatic mice. Acupuncture also reduced the CD4 +IL-17A+ cell proportion and counts in BALF. Conclusion Acupuncture effectively protects lung function and attenuates airway inflammation in the OVA-induced mouse model of asthma, which supports the role of acupuncture as a potential therapy in asthma treatment.