The Establishment And Established Method Contrast Of Animal Models Of Rabbit Benign Tracheal Stenosis

Background and objective:The airway(tracheobronchus) stenosis is a common disease in the respiratory system, which is a morbid disease that is challenging to manage. Historically, external trauma and infection of the airway have been the primary causes of tracheobronchial stenosis. However, sequelae of intubation have become the primary etiology. But in recent years, with the improvement of emergency and respiratory support technology, benign stenosis caused by endotracheobronchial intubation and mechanical ventilation has gradually increased.A variety of interventional techniques to treatment tha airway stenosis have recently been developed, but the effect is insufficient. It is necessary to study the animal models of tracheal stenosis. We hypothesized that injure the tracheal mucosa and cartilaginous rings can lead to tracheal stenosis and want to establish simple and reliable animal models of tracheal stenosis. In addition, we compare the diffierent measures of establishing models. The purpose of this study is therefore to establish reliable and simple animal models of tracheal stenosis after injure the tracheal mucosa and cartilaginous, and to provide a platform for the research of the pathogenesis, developing, preventing restenosis, or exploring new treated techniques of benign tracheobronchial stenosis. Materials and methods:Forty-five New Zealand rabbits were randomly divided into three groups, the group A(tracheal mucosa injury group, orally nylon brush scratch, n=15), the group B(tracheal cartilage injury group, surgical incise the tracheal cartilage and then closed, n=15), and the group C(tracheal mucosa and cartilage injury group, incise the cartilage trachea and then closed after scraping of tracheal mucosa with a nylon brush, n=15). We use chest MSCT scanning confirm the stenosis region and measure the degree of stenosis. The animals were sacrificed on 2, 4 weeks after operation respectively, tracheal samples were obtained, and microscopic observations were conducted with HE staining.Statistical analysis: All data are expressed as ameans±standard deviation. Using SPSS17.0 software, data of the three groups were compared by one-way analysis of variance, Independent-samples T test was used to compare data on 2 weeks and 4 weeks after operation. Differences were considered statistically significant at P<0.05. Results:1. The successful rate of tracheal stenosis: The success rate of nylon brush scratch and incise the tracheal cartilage was 100%(15/15). According to the tracheal stenosis which is found by biopsy, the success rate of rabbit model of tracheal stenosis: the group A was 80%(12/15); the group B was 93.3%(14/15); and the group C was 86.7%( 13/15); the overall success rate was 86.7(39/45).2. Diagnostic Imaging and the degree of tracheal stenosis: Chest MSCT can be uesd to diagnose tracheal stenosis, we measured and calculated the degree of tracheal stenosis in the chest MSCT scan. Two weeks after the operation, the degree of tracheal stenosis on the group A was(41.5±8)%, the group B was(51.4±9.9)%, and the group C was(58.4±7.9)%;Four weeks after the operation, the degree of tracheal stenosis on the group A was(61.7±8.8)%, the group B was(69.6±6.1)%, and the group C was(78.5±4.2)%. There was no significant difference of the tracheal stenosis between the group B with the group A and the C in both two and four weekes after the operation(p>0.05), while between the group A and the group C, there was a significant difference of tracheal stenosis in both two and four weekes after the operation(p <0.05).3. Pathological examination: All the stenosis region of trachea displayed wall thickening by inflammatory infiltrate and fibrosis. Necrosis and fibrosis were mainly observed in the mucosa and adventitia, occupying the region of the injured trachea wall. Granulation tissue predominated in the surface of tracheal mucosal, leading to partial obstruction of the lumen. The inflammatory infiltrate, consisting mainly of eosinophils, lymphocytes and plasma cells, predominated in the mucosa and submucosa. In all specimens, we observed the desquamation of respiratory epithelium. And in some specimens we observed collapse of destroyed cartilage. Conclusions:Injuring tracheal mucosa, cartilage, or both injuring mucosa and cartilage can successfully established rabbit model of benign tracheal stenosis, and three methods can create different degrees of tracheal stenosis animal model, meet the clinical different experimental needs. Compared with the traditional method, these model is similar to patient of benign tracheal stenosis morphologically and histologicaly,which are easy to operate, have lower animal mortality and shorter experimental period,can serve in the research of treatment of benign tracheal stenosis.