X线外照射抑制兔气道良性狭窄模型支架置入后粘膜增生的研究

发布时间：2018-05-05 18:25

本文选题：动物模型 + 放疗　；参考：《郑州大学》2017年硕士论文

【摘要】：背景和目的:气道狭窄是临床上常见的呼吸系统疾病,它是指由各种原因导致的气管及(或)支气管阻塞或外压性狭窄,从而导致远端的阻塞性肺炎、阻塞性肺不张、或阻塞性肺气肿,在临床上常表现为胸闷、气短等缺氧症状,严重狭窄可导致重度呼吸困难,加之痰液排出不畅甚至可导致窒息死亡,必要时需急诊行气管插管或气管切开解除狭窄,改善症状。其按致病因素可分为良性气道狭窄和恶性气道狭窄,国内导致良性气道狭窄的病因大多数为气管支气管结核,其次是气管插管或气管切开等。气道良性狭窄的治疗既往多以外科手术切除为主,常见的手术方式有段性切除+端端吻合术、袖状切除+气道成形术,术后吻合口狭窄发生率高,而且患者严重的气道狭窄导致无法气管插管,无法机械通气,自然无法全麻进行外科手术。近年来气道内支架置入快速解除气道狭窄,缓解呼吸困难可取得立竿见影的效果,已得到广大临床医生的认可,随着新型介入材料的研发,介入技术越来越多的应用于良性气道狭窄疾病的治疗,而且也逐渐替代外科手术成为气道良性狭窄的首选,常见的介入手术治疗包括:腔内消融、球囊扩张、内支架置入等,然而气道内支架置入后的一些并发症严重制约了其在良性气道狭窄治疗的推广,其中最主要的是支架置入后气道再狭窄,其病因多是由支架置入后肉芽组织过度增生所致,如何预防肉芽组织增生将对气道再次狭窄的预防有深远意义。自从1895年伦琴发现X射线以来,放射治疗在恶性肿瘤治疗方面取得了很大发展,放疗设备的不断更新,使得放疗亦常见用于良性病变的治疗,如心血管支架置入后再狭窄的预防及皮肤瘢痕组织的治疗,本实验通过建立兔良性气道狭窄模型支架置入后X线外照射处理,比较不同剂量组下气道的狭窄程度,探索X线外照射对兔气道良性狭窄模型支架置入术后肉芽组织增生的抑制作用。材料和方法:1.气道良性狭窄模型建立取健康的4月月龄新西兰大耳兔32只,不限雌雄,重2.5~3kg,通过兔颈部气管软骨环间切开气管,使用尼龙毛刷刮擦及无水酒精涂擦的方法制作气管良性狭窄动物模型,1个月后胸部CT扫描并气道三维重建观察气道狭窄程度;2.X线透视下将8mm*20mm的镍钛合金裸支架置入于气道良性狭窄模型的气管狭窄处以解除狭窄,后随机分为20Gy、30Gy、40Gy组及对照组,每组各8只实验兔,将20Gy组以7Gy/d剂量率照射2次,30Gy组以7Gy/d剂量率照射3次,40Gy组以8Gy/d剂量率照射3次,每次照射间隔5天,分别于4周及8周各处死各组一半实验动物,处死前1天行胸部螺旋CT扫描,统计各组气道狭窄率。实验结果:1.狭窄模型制作4周后所有动物均存活,狭窄程度约42-85%,根据Myer—Cotton狭窄分级(狭窄面积减少程度,I度狭窄为0-50%,Ⅱ度狭窄为51-70%,Ⅲ度狭窄为71-99%,Ⅳ度狭窄为完全堵塞)评估,其中Ⅰ度狭窄(4/32),Ⅱ度狭窄(18/32),Ⅲ度狭窄(10/32)。2.外照射处理4周后,20Gy组气道狭窄程度为(48.2±5.8)%;30Gy组气道狭窄程度为(35.25±5.5)%;40Gy组气道狭窄程度为(30.93±5.8)%;对照组气道狭窄程度为(58.4±7.9)%;外照射后8周后,20Gy组气道狭窄程度为(54.5±4.6)%;30Gy组气道狭窄程度为(38.8±5.3)%;40Gy组气道狭窄程度为(33.9±6.2)%;对照组气道狭窄程度为(70.7±5.1)%。外照射后4周和8周发现对照组实验兔气道平均狭窄程度与20Gy组、30Gy组、40Gy组平均气道狭窄程度之间均有统计学意义(p0.05);20Gy组与30Gy组、20Gy组与40Gy组实验兔的气道平均狭窄程度之间的差异则具有统计学意义(p0.05),30Gy组与40Gy组实验兔的气道平均狭窄程度之间的差异无统计学意义(p0.05)。20Gy组相比于对照组可以减少肉芽组织增生,其实验组兔子所接受剂量较少,因此放射相关并发症发生率较低,30Gy组相比于20Gy组在抑制肉芽组织增生方面有明显差异,且相对并发症较少,而40Gy组与30Gy组在抑制肉芽组织增生方面无明显差异,放射相关并发症较30Gy组严重,因此,推荐30Gy总剂量分次照射。3.病理及大体标本观察实验兔处死后,尸体解剖可见支架两端可见明显肉芽组织增生,表面可见白色脓性分泌物,气道粘膜局部水肿。光镜下可见气管粘膜全层伴有大量纤维母细胞增生,肉芽纤维组织增生,局部软骨可见炎细胞浸润破坏。部分小血管管壁纤维素性坏死伴炎性细胞浸润。黏膜下层及外层少量浆细胞为主的炎细胞浸润。气道管腔明显狭窄,气管黏膜全层可见少至中等量炎性细胞浸润。结论:1、通过兔颈部气管软骨环间切开气管,使用气道尼龙毛刷刮擦及无水酒精涂擦成功制作良性气管狭窄动物模型,4周后气道狭窄程度约(63.1±10.6)%;2、放疗可以有效抑制兔良性气道狭窄模型支架置入术后肉芽组织增生,本次实验推荐30Gy总剂量分次照射,对以后放射性气道支架的研发提供基础研究。
[Abstract]:Background and purpose: airway stenosis is a common clinical respiratory disease. It refers to trachea and (or) bronchial obstruction or external pressure stenosis caused by various causes, resulting in distal obstructive pneumonia, obstructive atelectasis, or obstructive emphysema, often characterized by hypoxic symptoms such as chest tightness, shortness of breath, and severe stenosis. The causes of severe respiratory distress, poor sputum discharge and even suffocation may lead to asphyxia. Emergency tracheal intubation or tracheotomy should be used to relieve the stenosis and improve the symptoms. The causes of the disease can be divided into benign airway stenosis and malignant airway stenosis. Endotracheal intubation or tracheotomy. The treatment of benign airway stenosis is mostly performed by surgical excision. The common surgical methods include segmental resection plus end to end anastomosis, sleeve resection plus airway plasty, high incidence of postoperative anastomotic stenosis, and severe airway stenosis leading to the failure of tracheal intubation, and no mechanical ventilation. Natural ventilation is not possible. In recent years, the internal airway stent implantation has been recognized by the vast number of clinicians. With the development of new interventional materials, more and more interventional techniques have been applied to the treatment of benign airway stenosis, and it is also gradually replaced by the new endotracheal stent. Surgery is the first choice for benign airway stenosis. Common interventional procedures include intracavitary ablation, balloon dilatation, and internal stent implantation. However, some complications after endobronchial stent implantation severely restrict the promotion of benign airway stenosis, most of which are airway restenosis after stent implantation, which are mostly caused by branches. How to prevent the proliferation of granulation tissue will be of profound significance for the prevention of re stenosis of the airway. Since the discovery of X ray in 1895, radiation therapy has made great progress in the treatment of malignant tumors, and the continuous renewal of radiotherapy equipment makes radiotherapy common for the treatment of benign lesions. Such as the prevention of restenosis after cardiovascular stent implantation and the treatment of skin scar tissue, the experiment was conducted to compare the stenosis degree of the lower airway in different dose groups by establishing the rabbit benign airway stenosis model after stent implantation, and to explore the inhibition of granulation tissue proliferation after external X-ray irradiation on rabbit airway benign stenosis model. Materials and methods: 1. healthy New Zealand rabbits were set up to establish healthy 4 month old New Zealand large ear rabbits, 32 of which were not limited to male and male, heavy 2.5~3kg. The trachea was cut through the tracheal cartilage ring in the neck of the rabbit. The animal model of benign tracheal stenosis was made by nylon brush scraping and anhydrous alcohol smear. The chest CT scan and airway three after 1 months. The degree of airway stenosis was observed by reconstruction. Under 2. X-ray fluoroscopy, 8mm*20mm NiTi bare metal stent was placed in the tracheal stenosis of the benign airway stenosis model, and then randomly divided into 20Gy, 30Gy, 40Gy and control groups, each group of 8 experimental rabbits, the 20Gy group was irradiated with 7Gy/d dose rate 2 times, the 30Gy group was irradiated with 7Gy/d dose rate 3 times, 40Gy group. At 8Gy/d dose rate 3 times, each time interval 5 days, 4 weeks and 8 weeks respectively, all the animals were killed in each group. The chest spiral CT scan was performed 1 days before death. The stenosis rate of each group was statistically analyzed. The results of the 1. stenosis model were all survived for 4 weeks, the stenosis was about 42-85%, according to the Myer Cotton stenosis classification (narrow area) The degree of reduction, the stenosis of I degree was 0-50%, the stenosis of degree II was 51-70%, the stricture of degree III was 71-99%, and the stenosis of degree IV was completely blocked. The stenosis of the airway was (48.2 + 5.8)% in 20Gy group and (35.25 + 5.5)% in 30Gy group after 4 weeks of stenosis (4/32), 18/32, and 10/32.2., and the airway stenosis in 30Gy group was (35.25 + 5.5)%; The degree of stenosis was (30.93 + 5.8)%, and the degree of airway stenosis in the control group was (58.4 + 7.9)%, and the degree of airway stenosis in group 20Gy was (54.5 + 4.6)% after 8 weeks of external irradiation, and the degree of airway stenosis in group 30Gy was (38.8 + 5.3)%, and the degree of airway stenosis in group 40Gy was (33.9 + 6.2)%, and the degree of airway stenosis in the control group was (70.7 + 5.1)%. The mean airway stenosis was statistically significant between the 20Gy group, the 30Gy group and the 40Gy group (P0.05). The difference between the 20Gy group and the 30Gy group, the 20Gy group and the 40Gy group was statistically significant (P0.05), and the difference between the average airway stenosis of the 30Gy group and the 40Gy group was the difference between the experimental rabbits and the 40Gy group. No statistical significance (P0.05) group.20Gy can reduce granulation tissue proliferation compared to the control group, the experimental group of rabbits received less dose, so the incidence of radiation related complications is lower, 30Gy group compared with the 20Gy group in the inhibition of granulation tissue proliferation is significantly different, and the relative complications are less, and the 40Gy group and the 30Gy group in the inhibition of meat. There was no significant difference in the proliferation of buds, and the radiation related complications were more serious than that in the 30Gy group. Therefore, the total dose of 30Gy was recommended for.3. pathological and gross specimens. After the death of the rabbit, the autopsy visible visible granulation tissue at both ends of the scaffold was visible, the white pus secretions were visible on the surface, and the local edema of the airway mucous membrane was visible. Under the light microscope, it was visible. The whole layer of trachea mucous membrane is accompanied by a large number of fibroblast proliferation, granulation tissue hyperplasia, local cartilage infiltration and infiltration of inflammatory cells. Some small vascular walls with cellulosic necrosis and inflammatory cells infiltrate. The submucosa and the outer layer of a small amount of plasma cells are mainly inflammatory cells. The airway lumen is obviously narrow and the whole layer of trachea mucous membrane can be seen less to the middle. Conclusion: 1, the animal model of benign tracheal stenosis was successfully made through tracheal incision between the tracheal cartilage ring of the rabbit's neck trachea and the tracheal nylon brush scraping and anhydrous alcohol smear. The degree of airway stenosis was about (63.1 + 10.6)% after 4 weeks. 2, radiotherapy could effectively inhibit the granulation tissue after stent implantation in rabbit benign airway stenosis model. The total dose fractionated irradiation of 30Gy is recommended in this experiment, which will provide basic research for the development of radioactive airway stent.

【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R56;R816.4

【参考文献】