Effect of electroacupuncture on expressions of acetylcholine and mucin 5AC in the lungs of rats with chronic obstructive pulmonary disease

Objective To observe the effect of electroacupuncture (EA) on the expressions of acetylcholine (ACh) and mucin 5AC (MUC5AC) in the lungs of rats with chronic obstructive pulmonary disease (COPD), and explore the mechanism of EA in treating COPD. Methods Thirty Sprague-Dawley (SD) rats were randomly divided into a control group, a COPD group, and an EA group, with 10 rats in each group. The control group was a group of normal rats. The COPD rat model was induced by cigarette smoke combined with lipopolysaccharide (LPS). The COPD rats were treated with EA at bilateral Feishu (BL 13) and Zusanli (ST 36) in the EA group, 30 min each time, once a day, successively for 14 d. The lung function was tested. The contents of ACh and MUC5AC in lungs and bronchoalveolar lavage fluid (BALF) were detected by enzyme-linked immunosorbent assay (ELISA). Pearson method was used to analyze the correlation between pulmonary function and the content of MUC5AC in lungs. The mRNA and protein expressions of MUC5AC in lung tissues were detected by real-time polymerase chain reaction (RT-PCR) and Western blot (WB), respectively. The immune response of MUC5AC was observed by immunohistochemistry. Results Eight rats were left in each group, and the other two died. Compared with the control group, the total airway resistance (Raw) increased significantly and dynamic compliance (Cdyn) decreased significantly in the COPD group ( P <0.01); compared with the COPD group, the Raw level declined significantly and Cdyn increased significantly in the EA group ( P <0.01). The contents of ACh and MUC5AC in the lungs and BALF were remarkably higher in the COPD group compared with those in the control group ( P <0.01, P <0.001); compared with the COPD group, the contents of ACh and MUC5AC were significantly lower in the EA group ( P <0.05, P <0.001). There was a negative correlation between MUC5AC content and lung function ( P <0.001). The mRNA and protein expressions of MUC5AC in the lungs were significantly higher in the COPD group than in the control group ( P <0.001); compared with the COPD group, the expressions were significantly lower in the EA group ( P <0.01). Compared with the control group, the immune response of MUC5AC in the airway epithelium significantly increased in the COPD group ( P <0.001); the immune response of MUC5AC was significantly lower in the EA group compared with that in the COPD group ( P <0.001). Conclusion EA treatment can improve the lung function of COPD rats, which may be related to its effect in the down-regulation of ACh and MUC5AC contents in the lungs as well as the inhibition of mucus hypersecretion.