125Ⅰ粒子覆膜支架对正常兔食管组织的放射性损伤实验研究

目的 观察125I粒子覆膜食管支架对于正常兔食管组织的放射性损伤.方法 将实验用兔分两组,每组各6只,实验组置入125I粒子支架(单颗粒子剂量22.2MBq ×3颗粒子),对照组植入无放射粒子的支架.于支架植入后2、4、8周分别取实验组和对照组兔2只,行食管造影,观察支架、粒子移位情况,处死后取标本行肉眼、显微镜观察.结果 支架释放过程及术后随访未发现125I粒子脱落.所有动物未发现穿孔等严重并发症.实验组术后2周,食管中部仅为轻微的病理学损伤,鳞状上皮明显增生.黏膜卜炎性细胞浸润.术后4周,出现肉芽组织增生,少量纤维组织增生.术后8周,肉芽组织、纤维结缔组织进一步增生.粒子相对处的食管组织损伤程度明显轻于粒子接触处食管组织.对照组支架中间部分食管与正常食管组织相似,可见食管鳞状卜皮轻增生.支架两端实验组和对照组局部增生食管组织覆盖支架,可见肉芽组织、纤维结缔组织明显增牛.结论 125I粒子支架置人正常兔食管壁组织造成病理性改变,主要表现为肉芽组织、纤维结缔组织增生,无出血、穿孔.

Radiation injury to normal rabbit esophagus induced by covered stent seeded with 125Ⅰ

Objective To evaluate the tissue response to the covered metallic stent loaded with radioactive 125I seeds in normal rabbit esophagus.Methods Twelve rabbits were randomlv assigncd into 2 groups.A covered metallic stent loaded with three 125I seeds set in sheaths Was implanted into the esophagus of the rabbit from experimental group(22.2 MBq for each seed,n=6).The rabbits of control group were implanted with stent without 125I (n=6).Two rabbits from each group underwent esophagus X-ray examination to detect migration of the stent and the 125I seeds at 2,4 and 8 weeks after stent implantation,respectively.And the animals were then sacrificed to observe the changes in esophagus.Results No 125I seed migration Was found during and after the implantation of the stent.No esophageal perforation was observed.Two weeks after stent implantation,such mild lesions were observed in the middle of the esophagus in experimental group as slight epithelial hyperplasia and submucosal inflammation.At 4th week after stentimplantation,granulation and fibrosis were observed,which became more obvious at 8th week after the procedure.The injury of esophageal tissue opposite to the 125I seed Was significantly milder than that of the tissue exposed to 125I seed.In control group,esophagus adjacent to the middle of the stent WaS similar to normal tissue,with slight epithelial hyperplasia.However,both ends of the stent were covered with marked hyperplasia epithelium in both groups,and severe granulation and fibrosis could be observed.Conclusion The main pathological changes of esophagus wall adjacent to the 125I seed are granulation and fibrosis.No bleeding or perforation occurs.