电针对慢性阻塞性肺病大鼠肺组织中p38丝裂原活化蛋白激酶信号通路介导的黏蛋白5AC表达的影响

目的:观察电针"足三里"对慢性阻塞性肺病(COPD)大鼠肺组织中表皮生长因子受体(EGFR)、肿瘤坏死因子α(TNF-α)、转化生长因子α(TGF-α)、白细胞介素-8(IL-8)、p38丝裂原活化蛋白激酶(p38MAPK)、黏蛋白5AC(MUC5AC)表达的影响,探讨电针治疗COPD大鼠气道黏液高分泌的作用机制。方法:SD大鼠随机分为正常组、模型组、电针组,每组10只。采用气管滴注脂多糖联合香烟烟熏的复合方法复制COPD大鼠模型。电针组取大鼠双侧"足三里"电针,每次30 min,连续2周。检测各组大鼠肺功能;HE染色法观察各组大鼠肺组织病理学变化;ELISA法检测血清、肺泡灌洗液(BALF)和肺组织内TNF-α、TGF-α和IL-8的含量;荧光定量PCR和Western blot法分别检测肺组织内EGFR、p38MAPK及MUC5AC mRNA和蛋白表达;免疫组织化学法检测肺组织中EGFR、p38MAPK及MUC5AC的表达。结果:与正常组比较,模型组大鼠肺组织及支气管有明显炎细胞浸润,管腔内出现大量黏液分泌物;用力肺活量(FVC)、第0.1秒用力呼气量(FEV0.1)、第0.3秒用力呼气量(FEV0.3)、FEV0.1/FVC、FEV0.3/FVC均明显下降(P<0.01);血清、BALF及肺组织内的TNF-α、TGF-α和IL-8的含量均显著升高(P<0.01),肺组织内的EGFR、p38MAPK及MUC5AC mRNA和蛋白表达水平及肺组织中的EGFR、p38MAPK和MUC5AC阳性表达水平均显著升高(P<0.01)。与模型组比较,电针组大鼠的炎细胞浸润和黏液高分泌有显著改善;FVC、FEV0.1、FEV0.3、FEV0.1/FVC和FEV0.3/FVC均明显上升(P<0.01,P<0.05);血清、BALF和肺组织内TNF-α、TGF-α和IL-8的含量和肺组织中的EGFR、p38MAPK及MUC5AC mRNA和蛋白表达水平含量及EGFR、p38MAPK和MUC5AC阳性表达水平均明显下降(P<0.01)。结论:电针"足三里"对COPD大鼠的气道黏液高分泌具有改善作用,其作用机制可能与抑制EGFR-p38MAPK信号通路介导的MUC5AC表达有关。

Electroacupuncture improves lung function by suppressing mucin-5AC mediated EGFR-p38MAPK signaling and inflammation reaction in chronic obstructive pulmonary disease rats

Objective To observe the effect of electroacupuncture(EA) at "Zusanli"(ST36) on the expression of epidermal growth factor receptor(EGFR), tumor necrosis factor α(TNF-α) transfer growth factor α(TGF-α), interleukin-8(IL-8), p38 mitogen-activated protein kinases(p38 MAPK), mucin-5 AC(MUC5 AC) and other related factors in chronic obstructive pulmonary disease(COPD) rats, so as to reveal its underlying mechanisms in improving COPD. Methods A total of thirty male SD rats were randomly divided into normal control, model and EA groups, with 10 rats in each group. The COPD model was replicated using a combined method of tracheal infusion of lipopolysaccharide(LPS) and forced smoke-inhaling. EA(1—3 mA, 4 Hz/20 Hz) was applied to bilateral ST36 for 30 min, once daily for two consecutive weeks. The lung ventilation activities including the forced vital capacity(FVC) and forced expiratory volume(FEV) at 0.1 and 0.3 s(FEV0.1, FEV0.3) were detected. Histopathological changes of the middle lobe and bronchus of the right lung were observed after H.E. staining. The contents of TGF-α, TNF-α and IL-8 in the serum, bronchoalveolar lavage fluid(BALF) and superior lobe of the right lung were assayed by using ELISA, and the expression levels of EGFR, p38 MAPK and MUC5 AC proteins(inferior lobe of the left lung) and mRNAs(inferior lobe of the right lung) detected using Western blot, immunohistochemistry(strept avidin-biotin complex, SABC method) and real-time quantitative PCR, respectively. Results Compared with the normal group, the FVC, FEV0.1, FEV0.3, FEV0.1/FVC and FEV0.3/FVC levels were significantly decreased(P<0.01), while the contents of TNF-α, TGF-α and IL-8 in the serum, BALF and lung tissues, expression levels of EGFR, p38 MAPK and MUC5 AC mRNAs and proteins, and the immunoactivity of EGFR, p38 MAPK and MUC5 AC in the lung tissues were significantly increased in the model group(P<0.01). After EA intervention, the decreased levels of the FVC, FEV0.1, FEV0.3, FEV0.1/FVC and FEV0.3/FVC, and the increased levels of the abovementioned genes and proteins were all reversed in the EA group(P<0.01, P<0.05). After modeling, the bronchial walls were thickened, with enlarged alveolar cavities, fractured alveolar walls, obvious inflammatory cell infiltration, and rich mucus secretion in the lumen, which was relatively milder in the EA group. Conclusion EA of ST36 can improve the ventilation function in COPD rats, which may be associated with its function in down-regulating the levels of TNF-α, TGF-α, IL-8, EGFR, p38 MAPK and MUC5 AC mRNAs and proteins in the lung tissues, inhibiting EGFR-p38 MAPK signaling mediated expression of MUC5 AC.