An Experimental Study On Airway Inflammation And Pulmonary Arterial Remodeling In A Rat Model With Chronic Bronchitis And Obstructive Emphysema

Objective (1)To study the role of airway inflammation on pulmonary arterial remodeling in rats with chronic bronchitis (CB) and obstructive pulmonary emphysema (emphysema).(2)To evaluate the relation between nuclear factor κB ( NF-κB ) on airway inflammation and pulmonary arterial remodeling.Methods (1) Twenty-one Wistar rats were randomly assigned to three groups: a four-weeks CB and emphysema group (group A, n=5), a six-weeks CB and emphysema group (group B, n=8), and normal control group (group C ,n=8). The rats of CB and emphysema were established by intratracheal instillation of lipopolysaccharide (LPS, 200μg ) at day 1st and 14th and daily exposed to cigarette smoke for two hours . (2) The arterial blood gas, pulmonary hemodynamics and total and differential cell counts in bronchoalveolar lavage fluid (BALF) were measured, the pathomorphological changes of airway inflammation, alveoli destruction and pulmonary arterial remodeling were observed by HE strains and triple strains, and the positive expression of NF-κB were observed by immunohistochemistry.Results (1) The total cells counts of BALF in group A and B were significantly higher than control group. It also showed a marked increase of neutrophils and lymphocytes in group A and B , respectively. The characteristic pathological changes of CB and emphysema were also observed in group A and B. In group A, there were main neutrophils infiltration into the airway walls, while lymphocytes in group B.(2) Compared with group C, arterial pressure of oxygen (PaO2) were normal but pulmonary hemodynamics were abnormal in group A and B. The level of right ventricular systolic pressure (RVSP), the mean pulmonary arterial pressure (mPAP ), the ratio of the weight of right ventricle/ left ventricle and septum (RV/LV+S) in group A and B were significantly higher than control group(p <0.05).The amount of muscular artery in group A and B were significantly more than group C(p <0.05) (3) The positive expression of NF-κB in inflammation cells, airway epithelia ,alveoli epithelia around airways and vasa in group A and B showed significantly more than control group(p<0.05).Conclusions (1) It was a perfect rat model with chronic bronchitis, obstructive emphysema and pulmonary hypertension by cigarette smoke and instillation of LPS . The more time of cigarette smoke on rats , the more lymphocytes of their airway walls.(2)The pulmonary arterial remodeling , pulmonary artery hypertension and the right ventricular hypertrophy in rats with CB and emphysema was observed whereas hypoxia had not been present, it indicated the airway inflammation of rats with CB and emphysema might play an important role in the pulmonary arterial remodeling. (3)The expression of NF-κB in epithelial cells and inflammation cells of airway and vascular was positive, while negative expression in endothelial cells of pulmonary arteries in group A and B, it indicated the levels of NF-κB were closely relative to airway inflammation.