Effect of electroacupuncture on pulmonary function and M1 polarization of alveolar macrophages in rats with chronic obstructive pulmonary disease

Yin LI

ABSTRACT

OBJECTIVE:

To observe the effect of electroacupuncture (EA) at "Zusanli" (ST36) and "Feishu" (BL13) on M1 polarization of alveolar macrophages (AM) in rats with chronic obstructive pulmonary disease(COPD), so as to explore its anti-inflammatory mechanism underlying improvement of COPD.

METHODS:

Forty SD rats were randomly divided into normal and normal＋EA, COPD model and COPD＋EA groups (n＝10 in each group). The COPD model was established by simple fumigation. EA (4 Hz/20 Hz, 1 to 2 mA) was applied to bilateral ST36 and BL13 for 30 min, once every other day for 2 weeks. The pulmonary function including the forced vital capacity (FVC), forced expiratory volume in 0.1 and 0.3 s (FEV0.1, FEV0.3, FEV0.1/FVC, and FEV0.3/FVC) was detected by using a small animal respiratory function detector. Histopathological changes of the lung were displayed by H．E. staining. The contents of tumor necrosis factor-α (TNF-α) and induced nitric oxide synthase (iNOS) in the broncho alveolar lavage fluid (BALF) were assayed by ELISA. The expression of M1 polarization markers (CD86，iNOS), myeloid differentiation factor 88(MyD88) and nuclear factor-κB p65(NF-κB p65) in AM were detected by Western blot and quantitative real time-PCR, separately. The distribution and expression of CD86 in the lung were detected by immunohistochemistry.

RESULTS:

Following modeling, the levels of FVC, FEV0.1, FEV0.3, ratios of FVE0.1/FVC and FEV0.3/FVC were significantly decreased (P<0.01), while the contents of TNF-α and iNOS in the BALF, expression of CD86, iNOS, MyD88 and NF-κB p65 mRNAs and proteins in the AM, and CD86 immunoactivity in the lung were significantly increased in the model group relevant to the normal group (P<0.01). After the intervention, the decrease of the lung function and increase of the above-mentioned genes and proteins were all reversed in the COPD＋EA group (P<0.05, P<0.01).

CONCLUSION:

EA at ST36 and BL13 can reduce pulmonary inflammation in COPD rats, which may be related to its function in inhibiting M1 polarization of AM via down-regulating MyD88/NF-κB p65 signaling pathway.