The Improvement And Evaluation Of Rat Asthma Model

ObjectiveTo establish the rat asthma model through pump and ultrasonic atomization, and explore difference of two ways by lung histopathology, cytology analysis of bronchial alveolar lavage fluids (BALF), serum immunoglobulin E ovalbumin (OVA), specificity immunoglobulin E and airway resistance, investigate the influences of different concentration of OVA to rat asthma model. We provide laboratory evidences by improve the rat asthma model and make it more suitable to the research of pathogenesis of asthmaMethodsMale Sprague-Dawley (SD) rats (4 weeks) were given an intraperitoneal injection of 1 ml 10% OVA complexed with 10% aluminum hydroxide gel and the inactived Bacillus pertussis on days 0.Two weeks after sensitization, Forty male SD rats were randomly divided equally into five groups. The rats of control group inhaled 0.9% sodium chloride through Ultra method in the challenge stage. The rats in Ultra group inhaled 2% OVA 30 minutes by Ultra atomizer,three times a week,for 6 weeks to sensitize their airways; And The rats in the three Pump groups inhaled 1%,2%,4% OVA respectively 10 minutes by Pump Atomization,three times a week,for 6 weeks to sensitize their airways.All the rats of the different groups were anesthetized 24h afer the last challenge for assessment, to be detected by pulmonary function,then to be killed after obtaining blood from inferior vena cava. IgE and SIgE in blood plasma was analyzed by ELISA. The left lobe of the lung bronchoalveolar lavage(BAL) was performed to evaluate the airway inflammation. After BAL,the right lobe of the lung was removed for histological examination and were stained with HE, Masson and PAS.Results1. General observation of the animalsRats in Ultra group and pump group appeared appeared visible respiratory distress signs (dysphoria, polypnea, contraction of accessory respiratory muscles and cyanosis). However, rats in control group were almost the same:breathing steadly, moving swiftly.2 Lung histopathology2.1 Pathological sectionThe lung histopathology of the control group, airway inflammation detected no significant changes, without bronchial wall thickening in the lungs, bronchial lumen regulation, epithelium mucosae well-arranged, non-infl ammatory exudate within the lumen.A large number of inflammatory cellular infiltration around the bronchial can be seen in the Ultra and Pump group, including:EOS, neutrophils, macrophages and lymphocytes, etc.; There can be seen EOS in the pulmonary mesenchymal and alveolar space,mucus plug in bronchus, injuries, fracture in the airway epithelium thickening of the basilar membrane with the irregular shape, hyperplasia of smooth muscle.2.2 The comparation of each group on the lung histopathology1) The score of inflammatory cell infiltration in ultra group and pump group were higher compared with control group (P<0.01);That was not statistically different in ultra group, pump group and each pump group (P>0.05).2) EOS around bronchus wall in Ultra group and pump group was significantly more compared with control group (P<0.01); There was no significant difference in ultra group, pump group and each pump group (P>0.05).3)Collagen deposition and goblet cells proliferation, mucus secretion were significantly increased in Ultra group and pump group compared with control;And these parameters in pump group were higher than those in ultra group; However, there was no significant difference in each pump group(P>0.05).3. The comparation of each group on the number of BALF cells1) The number of BALF cells in Ultra group and pump group was significantly increased compared with control group (P< 0.01);however,there was no statistically significant difference in ultra group, pump group and each pump group (P>0.05).2) Cell percentage of EOS and lymphocyte in Ultra group and pump group were higher compared with control group(P<0.01), especially for EOS; There was no significant difference in ultra group, pump group and each pump group (P>0.05).4. The comparation of each group on the level of IgE and SIgETotal and special serum IgE level in Ultra group and pump group was markedly enhanced compared with control group(P<0.01); and those in pump group were much higher than those in Ultra group(P< 0.01);However,there was no significant difference in each pump group (P >0.05).5. The comparation of each group on the airway resistance1) Aerosol histamine induced airway hyperresponsiveness, with the increasing of the dose of the histamine,the Raw value is higher and higher.2) Raw value in Ultra group and pump group was significantly increased compared with control group(P<0.01); And airway responsiveness in pump group higher than that of Ultra group(P<0.05); However,there was no significant difference in each pump group (P> 0.05).Conclusions1)OVA mixed with aluminum hydroxide gel and the inactivation Bacillus pertussis sensitized rats successfully, and inhaling OVA with pump and Ultra methods to challenge established the rat asthma model successfully. 2)The pump method is superior to the traditional Ultra method to challenge the rat asthma model.3)In some range the challenge dose of OVA has no obviously difference to established the rat asthma model...