Effect of electroacupuncture on the expression of autophagy related protein in lung tissue of rats with chronic obstructive pulmonary disease

Abstract

To observe the effect of electroacupuncture (EA) at "Zusanli" (ST36) and "Feishu" (BL13) on the expression of autophagy related proteins in the lung tissue of rats with chronic obstructive pulmonary disease (COPD), so as to explore the mechanism of EA underlying improvement of COPD. Thirty male SD rats were randomly divided into normal, model and EA groups (n=10 in each group). The COPD model was established by intratracheal infusion of Lipopolysaccharide (LPS, 1 mg/kg) and exposure in cigarette smoke. EA was applied to bilateral ST36 and BL13 for 30 min, once every other day for 2 weeks. The pulmonary function (forced vital capacity ［FVC］, forced expiratory volume in 0.1 s and 0.3 s ［FEV0.1, FEV0.3］, FEV0.1/FVC and FEV0.3/FVC) was detected by animal pulmonary function analysis system. Histopathological changes of the airway and lung were displayed by H.E. staining. Autophagosomes in the airway and lung tissues were observed by electron microscope. The expression of AMP activated protein kinase (AMPK), mammalian target of rapamycin (mTOR), Unc-51 like autophagy activating kinase 1(ULK1), autophagy related protein ATG6(Beclin1)mRNAs in lung tissue were examined by quantitative real-time PCR. The expression of AMPK, mTOR, ULK1, Beclin1 and microtubule-associated protein 1 light chain 3 (LC3)proteins in lung tissue were examined by Western blot. The contents of tumor necrosis factor α (TNF-α) and interleukin 6 (IL-6) in the broncho alveolar lavage fluid (BALF) were assayed by ELISA. Following modeling, the FVC, FEV0.1, FEV0.3, FEV0.1/FVC and FEV0.3/FVC levels were significantly decreased (P<0.01), the infiltration of inflammatory cells and the increase of autophagosomes were obvious in airway and lung tissue, the mRNA and protein expression of AMPK, ULK1, Beclin1 and the ratio of LC3Ⅱ/LC3Ⅰ were increased (P<0.01), while the mRNA and protein expression of mTOR were decreased (P<0.01), the contents of TNF-α and IL-6 in the BALF were increased in the model group compared with the normal group (P<0.01). After EA intervention, all the indexes mentioned above were completely reversed in the EA group relevant to the model group (P<0.01, P<0.05). EA at ST36 and BL13 can improve the lung function of COPD rats, which may be related to its effects in inhibiting the autophagy level and reducing the inflammation response in the lung.