鱼腥草提取物对慢阻肺大鼠肺组织ACE2及p38MAPK通路的影响

Effects of Houttuynia Cordata Extract on ACE2and p38MAPK Pathway in Lung Tissue for Rats with Chronic Obstructive Pulmonary Disease

目的:探究鱼腥草提取物对慢阻肺大鼠肺组织血管紧张素转换酶2(ACE2)及p38丝裂原活化蛋白激酶(p38MAPK)通路的影响。方法:清洁级SD大鼠60只,随机分为空白组、模型组、富露施组及鱼腥草水提物低、中、高剂量组,各10只。除空白组外大鼠通过烟熏和脂多糖(LPS)气道滴入方法建立慢阻肺模型,空白组大鼠不做任何处理。第2次注射LPS后起,鱼腥草水提物低、中、高剂量组每天给药量分别为0.27g/200g、0.54g/200g、1.08g/200g,富露施组为10.8g/200g,其余两组给予等量蒸馏水。给药4周后,测定大鼠用力肺活量(FVC)、第0.1秒用力呼气容积(FEV0.1)和呼气峰流速(PEF);统计肺泡灌洗液白细胞数目及各分类比;苏木精-伊红(HE)染色观察肺组织病理变化;蛋白质印迹(Western blot)检测肺组织ACE2、p38MAPK、p-p38MAPK水平。结果:造模后大鼠FVC、FEV0.1、PEF水平较空白组均显著降低(P<0.05),富露施、鱼腥草水提物干预后FVC、FEV0.1、PEF水平较模型组均显著升高(P<0.05),且有剂量依赖关系。模型组肺泡灌洗液白细胞数较空白组显著升高(P<0.05),经富露施、中及高剂量鱼腥草水提物干预后白细胞数较模型组显著下降(P<0.05),但仍高于空白组(P<0.05);各组间巨噬细胞比率差异无统计学意义(P>0.05);模型组、富露施组和鱼腥草水提物低剂量组淋巴细胞比率较空白组显著下降(P<0.05);造模后中性粒细胞比率较空白组均显著升高(P<0.05),各治疗组中性粒细胞比率较模型组均显著降低(P<0.05)。HE染色发现,模型组支气管壁有大量炎性细胞附着,气管黏膜上皮坏死、脱落、杂乱,杯状细胞及腺体显著增生;富露施、鱼腥草水提物干预后支气管炎症及破坏程度明显较轻。Western blot结果显示,模型组肺组织ACE2水平较空白组显著升高(P<0.05),富露施、鱼腥草水提物干预后ACE2水平较模型组显著升高(P<0.05);各组大鼠肺组织p38MAPK水平无显著差异(P>0.05);模型组肺组织p-p38MAPK水平较空白组显著升高(P<0.05),富露施、鱼腥草水提物干预后p-p38MAPK水平较模型组显著降低(P<0.05)。结论:鱼腥草水提物能明显减轻慢阻肺大鼠的肺脏损伤程度,其机制可能与ACE2活化及p38MAPK通路受到抑制有关。

Objective：To investigate the effect of Houttuynia cordata extract on angiotensin converting enzyme 2（ACE2）and p38 mitogen activated protein kinase（p38 MAPK） pathway in rats with chronic obstructive pulmonary disease（COPD）.Methods：Sixty clean grade SD rats were randomly divided into blank group,model group,Fluimucil group and water extract of Houttuynia cordata in low,medium and high dose groups,10 rats in each group.In addition to the blank group,rats were established of COPD model by smoking and lipopolysaccharide（LPS） airway instillation method,and the blank group rats did not do any treatment.After the second LPS injection,low,medium and high dose of water extract of Houttuynia cordata groups were given water extract of Houttuynia cordata 0.27 g/200 g,0.54 g/200 g,1.08 g/200 g everyday,Fluimucil group was given Fluimucil10.8 g/200 g everyday,and the other two groups were given equivalent distilled water.After four weeks of administration,forced vital capacity（FVC）,forced expiratory volume at 0.1 s（FEV0.1） and peak expiratory flow（PEF） were measured;The number of white blood cells in bronchoalveolar lavage fluid and the ratio of each classification were counted;The pathological changes of lung tissue was observed by hematoxylin eosin（HE）;And the levels of ACE2,p38 MAPK and p-p38 MAPK in lung tissues were detected by the Western blot.Results：After modeling,the FVC,FEV0.1 and PEF levels of rats were significantly lower than the blank group（P〈0.05）,the FVC,FEV0.1,PEF levels after the Fluimucil and water extract of Houttuynia cordata intervention were significantly higher than those in the model group（P〈0.05）,and in a dose dependent manner.The white blood cell counts in bronchoalveolar lavage fluid increased significantly than the blank group（P〈0.05）,and the white blood cell counts decreased significantly than the model group after the Fluimucil,medium dose and high dose water extract of Houttuynia cordata intervention（P〈0.05）,but still higher than the blank group（P〈0.05）,there was no significant differences between groups of macrophage ratio（P〈0.05）;The lymphocyte ratios of the model group,the Fluimucil group and the low dose water extract of Houttuynia cordata group were significantly lower than that of the blank group（P〈0.05）;After modeling,the neutrophil ratios were significantly higher than that in the blank group（P〈0.05）,and the neutrophil ratios in each treatment group were significantly lower than that in the model group（P〈0.05）.HE staining showed that there were a large number of inflammatory cells attached to the bronchial wall in the model group,the mucosal epithelium of trachea became necrosis,abscission and messy,goblet cells and glands proliferated markedly;The bronchitis and the degree of destruction were obviously lighter after Fluimucil and water extract of Houttuynia cordata intervention.The results of Western blot showed that the level of ACE2 in lung tissue of model group was significantly higher than that in the blank group（P〈0.05）,and the level of ACE2 was significantly higher than that of the model group after Fluimucil and water extract of Houttuynia cordata intervention（P〈0.05）;There was no significant difference in the levels of p38 and MAPK in lung tissues of rats in each group（P〈0.05）;The level of p-p38 MAPK in lung tissue of model group was significantly higher than that of the blank group（P〉0.05）;The levels of p-p38 MAPK were significantly lower than those in the model group after Fluimucil and water extract of Houttuynia cordata intervention（P〈0.05）.Conclusion：Water extract of Houttuynia cordata can significantly alleviate the lung injury in COPD rats,and its mechanism may be related to the activation of ACE2 and the inhibition of p38 MAPK pathway.