NF-κB表达水平与大鼠慢性阻塞性肺疾病气道、肺血管重构的相关性

The correlation between the expression of NF-κB and the airway remodeling,pulmonary vascular reconstruction in rats with chronic obstructive pulmonary disease

目的探讨NF-κB的表达水平与大鼠慢性阻塞性肺病(COPD)气道、肺血管重构的相关性。方法 24只♂SD大鼠随机分为4组。正常对照组(A):正常饲养4周;慢支组(B):于实验d1、14经气道内注入脂多糖(LPS),200μg/次,4周后检测;COPD组(C):d1、14经气道内注入LPS,200μg/次,熏香烟1h,共4周;COPD并肺动脉高压组(D):d1、14经气道内注入LPS,200μg/次,熏香烟1h/d,共6周,实验的最后2周在熏香烟的同时,给予18%低氧8h/d。各组测定气道阻力、肺血流动力学和右心室肥厚指数,观测气道炎症,气道重构以及肺小动脉的病理形态学改变,用免疫组化检测各组肺组织中NF-κB蛋白的表达,RT-PCR、Western blot检测肺组织中mRNA、蛋白的表达。结果①与A组相比,C、D组气道阻力明显增大(P<0.05)。②C、D组RVSP、mPAP和RV/LV+S都明显高于A组(P<0.05)。③与A组比较,C、D组气道重构指标细支气管管壁厚度与气管外径比值(MT%)、管壁面积和气管总面积比值(MA%)均明显增高(P<0.05)。④与A组相比,C、D组肌化型动脉百分比增多(P<0.05);D组肺小动脉管壁厚度与血管外径比值(WT%)、管壁面积与血管总面积比值(WA%)比值增大(P<0.05)。⑤免疫组化示,C、D组NF-κB蛋白表达强于A组(P<0.05),C、D组间表达差异无显著性。⑥RT-PCR结果说明,与A组相比,C、D组NF-κB mRNA表达明显增强(P<0.05)。C组与D组间NF-κB mRNA表达也有差异(P<0.05)。⑦Western blot电泳结果显示,与A组相比,C、D组NF-κB蛋白表达明显增强(P<0.05),D组较C组NF-κB蛋白表达增强(P<0.05)。结论 COPD早期已出现肺血流动力学变化,随疾病进展出现进行性加重的肺血管、气道重构,同时NF-κB的表达逐渐增强,说明NF-κB与COPD的肺血管、气道重构有关。

Aim To investigate the correlation between the expression of NF-κB and the airway remodeling,pulmonary vascular reconstruction in chronic obstructive pulmonary disease（COPD）.Methods 24 SD rats were divided into 4 groups randomly.Healthy control group（Group A）：rats were bred for 4 weeks in normal circumstance before baving a test.Chronic bronchitis group（Group B）：200μg lipopolysaccharide（LPS） was instilled intratracheally once at Day 1 and Day 14 in all rats to prepare them for the test 4 weeks later.COPD group（Group C）：200μg LPS was instilled intratracheally once at Day 1 and Day 14 in all rats.Then these rats were exposed to cigarette smoke 1 h/d for 4 weeks.Pulmonary hypertension from COPD group （Group D）：200μg LPS was instilled intratracheally once at Day 1 and Day 14 and the rats were exposed to cigarette smoke 1 h/d for 6 weeks.In the last 2 weeks chronic hypoxia （FiO2=0.18） 8 h/d were performed simultaneously.We studied airway resistance,pulmonary hemodynamic changes,and the structure of right ventricular wall.Airway wall remodeling and morphologic changes of small pulmonary artery were also observed.The positive expression of NF-κB in lung tissue was examined by immunohistochemistry （IHC）,RTPCR,and Western blot.Results ① Compared to group A,the airway resistance in group C and D were significantly increased （P0.05）.② The right ventricular systolic pressure（RVSP）,mean pulmonary arterial pressure （mPAP） and the ratio of the weight of right ventricle/left ventricle and septum（RV/LV＋ S） were higher in group C,D than in group A（P0.05）.③ compared with group A,the ratio of bronchial wall over external diameter（MT%） and the ratio of bronchial wall area over total area （MA%） were significantly higher in group CD（P0.05）.④ The muscularization of intra-alceolar arteries in group CD were more severe than in group A（P0.05）.The cross-sectional medial vascular wall area of pulmonary arteries were increased significantly in group D（P0.05）.⑤ Immunohistochemistry showed the expression of NF-κB protein in group CD were stronger than group A（P0.05）;there was no difference between C and D.⑥ RT-PCR displayed that compared with group A,the expression of NF-κB mRNA were increased in group CD （P0.05）.There were differences between group C and group D （P0.05）.⑦ Western blot showed that compared with group A,the expression of NF-κB protein in group CD were significantly increased（P0.05）.The expression of NF-κB protein in group D is higher than group C（P0.05）.Conclusions The changes of pulmonary hemodynamics had emerged at early COPD.With the progression of the disease,the airway remodeling and pulmonary vascular reconstruction aggravated progressively,while the expression of NF-κB was increased in lung tissue.There may be some relevance between the expression of NFκB and the airway remodeling,and pulmonary vascular reconstruction.