| Background and Objective Bronchial asthma is a common chronic respiratory disease. In recent years, for the reason of aggravated air pollution, the prevalence of asthma has been increasing year by year in the world. This has brought a serious economic and social burden in global countries and has increasingly become a serious public health problem. Allergic asthma is the most common type of asthmatic diseases charactered by elevated serum Ig E, higher mucus secretion and airway hyperresponsiveness.A variety of inflammatory cells including eosinophils, lymphocytes, macrophages, mast cells and inflammatory mediator network involve in the pathogenesis of allergic asthma. Although Th2 lymphocyte and related factors(such as IL-4, IL-5, IL-13, etc.) play a major role in the pathogenesis of allergic asthma,in recent years, the role of macrophages and associated cytokines in allergic asthma has beed getting more attention.Macrophage migration inhibitory factor(MIF) is an upstream of proinflammatory cytokines and pro-inflammatory cytokines, mainly from monocytes and macrophages, which can promote the secretion of various cytokines and involve in the pathogenesis of many diseases. Studies have shown that MIF involve in the disease progression of allergic asthma, which can regulate the expression of Th2 cytokines and play an important role in the pathogenesis of allergic asthma. To further understand the role of MIF in the pathogenesis of allergic asthma, this study was carried out in patients with allergic asthma and in a rat model. of allergic asthma respectively. It was divided into two parts: Part I: Expression of serum MIF, Eotaxin-2 and Ig E and their correlation in patients with acute exacerbation of allergic asthma; Part II: Effect on the expression of pulmonary tissue MIF and serum IL-4 by passivating NF-?B activation in a rat model of allergic asthma. The aim of this thesis is to investigate the role and significance of MIF in allergic asthma.Part ?: Expressions and Correlations of Serum MIF, Eotaxin-2 and Ig E in Patients with Acute Exacerbation of Allergic AsthmaMethods From September 2012 to October 2015, 30 hospitalised patients with acute exacerbation of allergic asthma(asthma group) and 25 healthy controls(control group), were recruited from the Department of Respiratory Medicine in the Second People's Hospital of Zhengzhou. Peripheral venous blood of healthy controls and patients in pre-and post-treatment asthma group were exsanguinated respectively,protein of serum MIF, Eotaxin-2, Ig E and peripheral blood eosinophil ratio(EOS%) were detected for all subjects. Pre- and post-treatment lung functions in patients of asthma group were also determinated. The relevant pre- and post-treatment indicators were performed comparison and correlation analysis.Results 1. Lung functions(including FVC% pred, FEV1, FEV1% pred, FEV1/FVC) in post-treatment asthma group was superior to that in pre-treatment asthma group, the difference was statistically significant(P <0.01). 2. Serum MIF levels in pre-treatment asthma group were significantly higher than that in post-treatment asthma group and healthy control group, the difference was statistically significant(P <0.01); when compared serum MIF levels in post-treatment asthma group and in healthy control group, the difference was not statistically significant(P> 0.05). 3. Serum Eotaxin-2 levels in pre-treatment asthma group were significantly higher than that in post-treatment asthma group and healthy control group, the difference was statistically significant(P<0.01); when compared serum Eotaxin-2 levels in post-treatment asthma group and in healthy control group, the difference was not statistically significant(P> 0.05). 4. Serum Ig E levels in pre-treatment asthma group were significantly higher than that in post-treatment asthma group and healthy control group, the difference was statistically significant(P<0.01); Serum Ig E levels in post-treatment asthma group were still higher than that in healthy control group, the difference was statistically significant(P <0.05). 5. EOS% levels in pre-treatment asthma group were significantly higher than that in post-treatment asthma group and healthy control group, the difference was statistically significant(P<0.01); when compared EOS% levels in post-treatment asthma group and in healthy control group, the difference was not statistically significant(P> 0.05). 6. Pearson correlation analysis showed that serum MIF in asthmatic patients was negatively correlated with FVC% pred, FEV1, FEV1% pred and FEV1/FVC(P<0.05). Serum Eotaxin-2 in asthmatic patients was negatively correlated with FVC% pred, FEV1, FEV1% pred and FEV1/FVC(P <0.01). Serum Ig E in asthmatic patients was negatively correlated with FEV1% pred and FEV1/FVC(P <0.05). 7. Pearson correlation analysis showed that serum MIF, Eotaxin-2, Ig E and EOS% in asthmatic patients was correlated with each other. Serum MIF was positively correlated with serum Eotaxin-2(r = 0.818, P <0.01); Serum MIF was positively correlated with serum Ig E(r = 0.778, P <0.01); Serum Eotaxin-2 was positively correlated with serum Ig E(r = 0.751, P <0.01). Serum MIF, Eotaxin-2, Ig E was positively correlated with EOS%, respectively(r = 0.532, P <0.01; r = 0.496, P <0.01; r = 0.444, P <0.01; respectively).Conclusions Serum MIF, Eotaxin-2, Ig E and EOS% level in patients with acute exacerbation of asthma was significantly higher compared with the healthy control group respectively.The parameters levels in post-treatment asthma group were significantly lower than that in pre-treatment asthma group. Moreover, each parameter was positively correlated with each other and was negatively correlated with lung functions. It suggests that MIF, Eotaxin-2, Ig E and EOS jointly involve in the pathogenesis of allergic asthma and is associated with the severity of the disease. Therefore, the parameters can be used as good monitoring indicators for clinical diagnosis and treatment and has better clinical application value.Part ?: Effect on the Expression of Pulmonary Tissue MIF and Serum IL-4 Level by Passivating the Activation of NF-?B in a Rat Model of Allergic AsthmaMethods According to the method of random number table, Wistar rats were divided into 4 groups:model group, sulfasalazine treatment group(SASP group),dexamethasone treatment group(DXM group) and control group. A rat model of asthma was prepared according to previously reported literature, and treatment groups were interfered with respective treatment. At the end of the experiment, IL-4 levels were detected by ELISA, and lung tissue were stained by HE, PAS or immunohistochemical staining. Pathological changes were observed and the data of expression of lung tissue MIF, NF-?B and bronchial mucosa goblet cells staining area were processed by Image-Pro Plus 6.0 image analysis software. At last the corresponding indicators were performed comparative study and correlation analysis.Results 1. Comparison of HE staining: In model group, all levels of bronchial were infiltrated by a massive inflammatory cells. At the same time, edema and loss of bronchial epithelium, bronchial stenosis,more mucus plug and smooth muscle proliferation were also observed. Moreover, lung tissue were also seen a massive infiltration with inflammatory cells and widened alveolar septum. In SASP and DXM group, the number of peribronchial inflammatory cells infiltration were significantly reduced. Edema and loss of bronchial epithelium, bronchial stenosis, mucus plug and smooth muscle proliferation were also mitigated. Meanwhile, a decreased infiltration with inflammatory cells and widened alveolar septum in lung tissue were also observed. In control group,the integrity of all levels of bronchial epithelial cells were observed. No significant inflammatory cells infiltration, bronchial lumen stenosis and smooth muscle proliferation were seen in all bronchuses or lung tissue. 2. Comparison of PAS staining: In model group, a mass of mucosa goblet cells hyperplasia and a lot of mucus plug in lumen were observed in all levels of bronchi, bronchioles and terminal bronchioles.In SASP and DXM group, a decreased of mucosa goblet cells hyperplasia and a few of mucus plug in lumen were observed in all levels of bronchi, bronchioles and terminal bronchioles. In control group, except for trachea, goblet cells were rarely seen in all levels of bronchial mucosa.The goblet cells area to total area of bronchial epithelium(%) in model group, SASP group, DXM group was significantly higher than control group respectively(P<0.01); The goblet cells area to total area of bronchial epithelium(%) in SASP group, DXM group was significantly lower than model group respectively(P<0.01); There was no significant difference between SASP and DXM group(P> 0.05). 3. Comparison of immunohistochemical staining:(1) Expression of lung tissue MIF protein: In model group, nigger-brown strong positive expression were seen mainly in the bronchial mucosa and submucosa. In SASP group and DXM group, brown positive expression were seen mainly in the bronchial mucosa and submucosa. In control group, weakly positive expression were seen mainly in the bronchial mucosa and submucosa. Expression of lung tissue MIF in model group, SASP group, DXM group was significantly higher than control group respectively(P<0.01); Expression of lung tissue MIF in SASP group and DXM group was significantly lower than model group respectively(P<0.01); There was no significant difference between SASP and DXM group(P> 0.05).(2) Expression of lung tissue NF-?B protein: In model group, nigger-brown strong positive expression were seen mainly in the bronchial mucosa, submucosa and inner or outer membranes of peripheral blood vessels. In SASP group and DXM group, brown positive expression were seen mainly in the bronchial mucosa, submucosa and inner or outer membranes of peripheral blood vessels. In control group, weakly positive expression were seen mainly in the bronchial mucosa and submucosa. Expression of lung tissue NF-?B in model group, SASP group, DXM group was significantly higher than control group respectively(P<0.01); Expression of lung tissue NF-?B in SASP group and DXM group was significantly lower than model group respectively(P<0.01); There was no significant difference between SASP and DXM group(P> 0.05). 4. Comparison of serum IL-4 levels by ELISA test: Serum IL-4 level in SASP, DXM and control group was significantly lower than model group respectively(P<0.01); There was no significant difference between SASP, DXM and control group(P> 0.05). 5. Correlation analysis of parameters: Pearson correlation analysis showed that lung tissue MIF, NF-?B, and serum IL-4 in asthmatic rats was correlated with each other. Lung tissue MIF was positively correlated with NF-?b(r=0.883,P<0.01); Lung tissue MIF was positively correlated with serum IL-4(r=0.707,P<0.01); Lung tissue NF-?B was positively correlated with serum IL-4(r=0.712,P<0.01).Conclusions There was overexpression of lung tissue MIF, NF-?B and serum IL-4 in allergic asthmatic rats. By using dexamethasone or sulfasalazine, a specific inhibitor of NF-?B, the activation of NF-?B could be passivated and lung tissue MIF expression was significantly inhibited. Therefore, the expression of IL-4 was downregulated and pulmonary inflammatory cells accumulations, airway constriction, mucus hypersecretion, airway remodeling and other pathological changes were further improved. It suggests that as an important target for the treatment of allergic asthma, MIF has a good prospect for the clinical application in the future. |
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