| Background & Objective: Airway stenosis is a common clinical disease of respiratory system,which refers to tracheal and(or)bronchial obstruction or adjacent tissue compression leads to tracheal narrow caused by various causes,resulting in distal obstructive pneumonia,obstructive atelectasis,or obstructive emphysema,and often manifested as chest tightness,dyspnea and other hypoxic symptoms,severe stenosis can lead to severe dyspnea,coupled with poor sputum discharge can lead to suffocation and death,emergency Tracheal intubation or tracheotomy to relieve stenosis and improve symptoms in necessary.According to the risk factors can be divided into benign airway stenosis and malignant airway stenosis,the majority cause of benign airway stenosis is trachea bronchial tuberculosis,followed by tracheal intubation or tracheotomy.The mainly treatment of benign airway stenosis is surgical resection,the common surgical way segmental resection and end-to-end anastomosis,sleeve resection and tracheal angioplasty,but the complication of postoperative anastomotic stenosis is high,as the patients with severe airway stenosis get not endotracheal intubation,not be mechanical ventilation,No general anesthesia for surgery naturally.with immediate effect to rapidly relieve airway stenosis and dyspnea,airway stent has been recognized by the majority of clinicians,In recent years,with the development of new interventional materials,interventional treatment technology is widely used in disease of benign airway stenosis,but also gradually become an alternative to surgery of benign airway stenosis preferred,the common interventional treatment include: endovascular ablation,balloon dilatation and stent implantation,some severe complications after stent implantation have severely restricted its promotion in the treatment of benign airway stenosis stent.One of the most important is the airway restenosis after stent implantation,mostly because of the excessive proliferation of granulation tissue after stent implantation,Radiation therapy has made great progress in the treatment of malignant tumors since the discovery of X-ray in 1895.radiotherapy is also widely used in the treatment of benign lesions,such as cardiovascular treatment of restenosis after stent implantation and scar tissue.The purpose of this study is to explore the inhibitory effect of external irradiation on granulation tissue proliferation after stent implantation in animal models of rabbit benign tracheal stenosis.Materials and Method: 1.to establish animal models of rabbit benign tracheal stenosis.30 healthy 4-month-old New Zealand ear whisper,Gender is not open-ended,cutting the trachea cartilage ring,then using nylon brush scraping and anhydrous alcohol inunction to make animal model of tracheal stenosis,after 1 months of chest CT scan and three-dimensional reconstruction to observe the degree of airway stenosis;2.The 8mm * 20 mm nickel-titanium alloy bare stent was placed in the tracheal stenosis of the airway benign stenosis model.The rabbits were randomly divided into 20 Gy,30Gy,40 Gy group with 8 rabbits in each group and 6 rabbits in control group,20 Gy group was irradiated twice at 7Gy / d dose rate,30 Gy group was irradiated 3 times at 7Gy / d dose rate,40 Gy group at 8Gy / d dose rate of irradiation 3 times,each irradiation interval of 5 days,respectively,The animals were sacrificed at 4 and 8 week,and the thoracic spiral CT scan was performed 1 day before sacrifice.The rate of airway stenosis was counted.Results: 1.After 4 weeks of stenosis model production,all animals survived,according to Myer Cotton assessment(based on Percentage of narrow area reduction,the?degree of stenosis is 0-50%,?degree of stenosis is 51-70%,the ? degree of stenosis is 71-99%,IV degree of stenosis is completely Obstructed),and the degree of stenosis was about 42-85%.The ?degree of stenosis(4/32),?degree of stenosis(18/32),? degree of stenosis(10/32)? 2.After external irradiation,At 4 weeks after operation,the degree of airway stenosis was(48.2±5.8)% in the 20 Gy group and(35.25±5.5)% in the 30 Gy group;(30.93±5.8)% in the 40 Gy group;(58.4 ± 7.9)%in the control group;at 8 weeks after operation the degree of airway stenosis was(54.5±4.6)% in 20 Gy group;(38.8±5.3)% in 30 Gy group and(33.9±6.2)% in the 40 Gy group;and(72.7±4.9)% in the control group.The mean stenosis of the airway in the control group was significantly different from that in the 20 Gy group,the 30 Gy group and the 40 Gy group(p <0.05)both at 4 weeks and 8 weeks.The difference between the 20 Gy group and the 30 Gy group,20 Gy group and 40 Gy group was statistically significant(p <0.05).The difference between the two groups was statistically significant(p <0.05).There was no significant difference in the mean stenosis between the 30 Gy group and the 40 Gy group.Compared with the control group,the 20 Gy group can reduce the granulation tissue proliferation,the experimental group of rabbits received less dose,so the incidence of radiation-related complications is low,30 Gy group compared to 20 Gy group in the inhibition of granulation tissue proliferation were significantly different,And less complications,and 40 Gy group and 30 Gy group in the inhibition of granulation tissue proliferation was no significant difference,radiation-related complications than 30 Gy group of serious,therefore,recommended 30 Gy total dose of radiation.3.Pathology and gross specimen observation In experimental rabbit autopsy : obvious hyperplasia of granulation tissue at the two ends of the stent,and white purulent secretion on the surface of the trachea.tracheal mucosal edema,Under the light microscope,there were a large number of fibroblasts in the lamina propria of the trachea,and the proliferation of granulation tissue and the expansion and congestion of the capillaries.The inflammatory cell infiltration was observed in the trachea mucosa.Conclusions: 1.the animal model of rabbit benign tracheal stenosis was successful made by tracheotomy on neck Incision tracheal cartilage ring and using of airway nylon brush and scraping and anhydrous alcohol inunction.4 weeks later,the degree of airway stenosis was about(63.1 + 10.6)% 2.Radiotherapy can effectively inhibit the proliferation of granulation tissue in the rabbit model of benign airway stenosis after stent implantation.This study recommended that the total dose of 30 Gy irradiation can be used.And to provide the basic research for the future research and development. |
PDF Full Text Request