Expression Of Basic Fibroblast Growth Factor And Nuclear Factor-κb And Effect Of Budesonide On Asthmatic Rats

Bronchial asthma is a chronic inflammation of airway, the notable pathological chatacter of which is chronic inflammation and hyperresponsiveness and remodeling.The main changes of airway remodeling are hypertrophy of airway smooth muscle and subepithelial basement membrane thickening and fibrosis,and hypertrophy of airway smooth muscle is characterized basic pathological changes.And airway remodeling is the considerable patho-foundation of non-reversible airflow choke and airway hyperresponsiveness. Up to now, the mechanism of asthmatic airway remodeling is not completely clear.So it is significant to study the patho-character and mechanisms of asthmatic airway remodeling to find the more effective treatment. Basic fibroblast growth factor(b-FGF) is an Heparin adhesion polypepeide,can promotion cell multiplication and differentiation and adhesion.Nuclear factor-κB (NF-κB) is an nuclear factor and widespread exists in many cells, can regulate the growth factors,cytokine, mediators of inflammation, chemotactic factor and enzymes to cause airway remodeling.This experiment is to study the expession of b-FGF and NF-κB in airway remodeling of asthma rats and the effect of budesonide intervention from setting up the model of airway remodeling of asthma rats,it can offer effective channel and wide thinking of the treatment and earlier period intervention of asthma.Materials and methods1.Objections and making the asthma model45 healthy and male SD rats, weighed (200±10)grams,aged 6-7 weeks, they were randomly divided into 3 groups: control group ( group A),hma group( group B), herapy group(group C) , every group had 15 rats.On the 1^st and 8^sr day ,rats of group B and C were injected 1ml 10% ovalbumin(OVA) suspension(containing 1ml normal saline, 100mg aluminum hydroxide, 100mg OVA) by intraperitoneal to sensitize them, rats of group A were injected 1 ml physiologic saline. On the 15^st day, rats of group B and C were challenged for 20 mimutes by inhaling 1% ovalbumin(once/every other day) in special made terrarium, rats of group A were challenged with physiologic saline. Rats of group C were inhaled budesonide half an hour after every challenge. The rats appear restlessness, accelerated breathing or immobility, abdominal muscle spasm, indicate that we make the asthma model successfully.2.Collecting the sampleAll the rats were anesthetized by Phenobarbital sodium(100mg for each rat), then opened the chest, intubated into pulmonary artery through right ventricle, using physiologic saline to lavage quickly, taken the middle lobe of right lung into 10% methanal to fix them, then imbed in paraffin within 24 hours. Slicing the samples by two direction: vertical and parallel to the airway, the thickness of each slice was 5μm, then make HE staining and immunohistochemistry staining. 3.Measure the thickness of airway smooth muscle and tracheal epitheliumUsing computer image analysis system, chosing completed cross section of brochhi, each section was quantified under a×400 objective microscope to measure the thickness of airway smooth muscle and tracheal epithelium. Then calculate the mean thickness as the last result..4.Determination of the expression of b-FGF and NF-κBOn immunohistochemistry staining slice, using computer image analysis system, chosing five representative filed of view randomly on each slice under high power lens(×400), selecting positive area and measuring the gray scale, then calculate the mean gray scale as the last result..5.Statistics analysisUsing SPSS15.0 statistical package to analyze, all the result were demonstrated by mean±standard deviation, using one-way ANOVA to compare the mean of each group affter the test of homogeneity of variance, linear correlation analysis was used to assess the relation of variables,α=0.05 is the significance level, P value less than 0.05 indicate statistical significance. Result1. The lung sampleThe lung samples of asthma rats were much larger and hyperaemia than those of control rats, there were few fibrae cyst in mesenchyma. Campared with those of asthma rats, the change above-mentioned were less than those from therapeutic group.2. HE stainingBronchi tracheal epithelium cells shedding, mucous interrupt, the plica were increased in the lung sample of asthma rats. There were lots of inflammatory cells(especially eosinophils and lymphocytes) under mucous and around airway wall. Few epithelium cells shedding, aieway mucous almost completed in the lungs of therapeutic group. Thickening of airway wall and infitration of inflammatory cells were both less than those in asthma group. There were not such changes in control group.3. Immunohistochemistry staining3.1 the thickness of airway smooth muscle and tracheal epithelium.The thickness of the airway smooth muscle and tracheal epithelium, in the model group was higher than that in control group and the therapeutic group of the same period,P<0.05;Therapeutic group was3.2 The expression of b-FGF on airwayb-FGF express on airway widely, for example, epithelial cells, smooth-muscle cells, fibroblasts cell,endothelial cells. The expression of the b-FGF was higher in the model group than that in control group and the therapeutic group of the same period,P<0.05.3.3 The expression of NF-κB on airwayon airway,NF-κB express in epithelial cells, smooth-muscle cells, endothelial cells.The expression of the NF-κB was also higher in the model group than that in control groupand the therapeutic group,P<0.05.3.4 linear correlation analysisThe expression of b-FGF was positive correlation with NF-κB in asthma rats (r=0.531,P<0.05);The expressions of b-FGF and NF-κB were positively correlated with the thickness of airway smooth muscle (r_b-FGF= 0.574 ,r_NF-κB=0.711, P < 0.05)and tracheal epithelium (r_b-FGF= 0.601, r_NF-κB=0.730,P < 0.05) . Conclusion1. b-FGF and NF-κB are tightly correlated with airway remodeling,and show synergistic action in the development of airway remodeling of asthma.2. Glucocorticoids can reduce the expression of b-FGF and NF-κB in the asthmaairway remodeling process.