摘要
目的评价125I籽源持续照射时壳聚糖涂层的聚乙丙交酯(PGLA)载体支架的体内降解性能和组织相容性。方法大鼠背部肌肉内植入装载2粒125I籽源的PGLA薄层片,单粒籽源表观活度为29.6×106Bq(0.8mCi)。于不同时相点检测载体支架的质量损耗和观察材料的形态结构变化,采用光镜和电镜观察植入部位的组织学反应,并定期进行X线摄片观察籽源移位情况。结果125I籽源薄层片在体内降解前2周,质量损耗仅约13%,与未受照组比较无明显差异;植入后第3周,质量损耗率达41%,降解速率较对照组加快,部分材料纤维开始出现断裂,纹理结构模糊,但仍保持形态结构的完整和一定的强度;大体观察可见材料周围有纤维结缔组织增生,至植入后4周,纤维结缔组织明显增厚将材料完全包裹固定,两者黏连难以分离。植入部位组织反应的光镜、电镜观察显示植入前2周,炎性细胞较多;4周时炎性细胞已很少,材料孔隙内及周围主要以成纤维细胞和胶原纤维为主,巨噬细胞增多且吞噬现象更明显,同时见有较多新生的骨骼肌细胞,未出现脓肿和坏死,照射组和对照组相近似。对比植入后2h、第3天、第1、2、3、4周的X光片可以发现,植入的两粒125I籽源相互之间、与大鼠骨性解剖结构之间的距离及两籽源轴线的相互角度无明显变化。结论壳聚糖涂层的PGLA薄层载体支架能有效维持体内125I籽源的空间分布,而且具有良好的组织相容性,应用于近距离放射治疗是安全有效的。
Purpose To evaluate the effect of continuous low-dose-rate irradiation delivered by ^125I seeds on degradation behavior and biocompatibility of chitosan-coated poly （lactie-glycolic acid） （PGLA） brachytherapy seeding carrier in vivo. Methods The chitosan-coated PGLA carrier loaded with two ^125I seeds was implanted into latero-spinal muscle of Sprague Dawley rat. The apparent radioactivity of each ^125I seed was 29.6 MBq. The weight loss and morphology change of the coated PGLA carrier were monitored at different degradation time. The tissue of the implanted site was observed by light microscopy （LM） and transmission electron microscopy （TEM）. X-ray photography was performed regularly to evaluate seedsmigration. Results Two weeks after implantation, the weight loss of PGLA carrier irradiated by ^125I seeds was about 13 %, which was not significantly different from that of the control group. Three weeks after implantation, the weight loss of irradiated group reached 41% and broken filaments and blur structure were observed, showing faster degradation rate than the control group. But the structure integrity and a certain degree of strength of the coated PGLA carrier remained. There were large mounts of fibrous tissue accrementition around the carrier sheet. Four weeks after implantation, ^125I seed carrier sheet was completely encapsulated and fixed by peripheral dense connective tissue and was difficult to detach from each other. LM and TEM observation on tissue of implanted site indicated that there were many inflammatory cells within 2 weeks post implantation and a little inflammatory cells 4 weeks after implantation. The pores in the degradated PGLA carrier were filled with fibroblasts and collagen fibers. The amount of macrophages increased and phagocytosis were obvious. Neogenesis of the skeletal muscle cells was observed and no abscessus and necrosis was found. There were no significant difference between the radiation group and control group. X-ray photography exhibited that the spatial location between the two ^125I seeds and between the ^125I seeds and bony structure of the rat didn＇t change significantly 2h, 3 day, 1 week, 2 weeks, 3 weeks and 4 weeks after implantation. Conclusions The chitosan-coated PGLA carrier can maintain the spatial distribution of ^125I seeds and their biocompatibility in rats. It is safe and effective to be used in brachytherapy.
出处
《复旦学报（医学版）》
CAS
CSCD
北大核心
2007年第2期233-238,共6页
Fudan University Journal of Medical Sciences
基金
上海市科委重点科技攻关项目(045211026)
