血管内放射抑制猪髂动脉球囊损伤后狭窄形成的动态观察及机制探讨

Dynamic Observations on the Effect of Pig Arterial Stenosis after Balloon Injury by End-ovascular Radiation

目的 :评价血管内放射抑制猪髂动脉球囊损伤后狭窄形成的可行性、有效性及其作用机制。方法 :小型家猪 13头 ,分为对照组 7头及实验组 6头。对照组左侧髂动脉先行造影及血管内超声检查 ,随后行球囊扩张成形术 ,最后置入置源管。实验组在上述处理基础上 ,通过置源管送入 1 92 Ir高剂量后装源取 2 0 Gy对受损髂动脉行放射治疗。术后第 3天、第 10天及第 2 8天各处死 2头猪 ,取损伤的髂动脉分别行苏木精 -伊红及 Masson染色 ,计算机图像分析系统分析形态学及组织学变化。结果 :对经球囊损伤后的猪髂动脉进行血管内放射在技术上是可行的 ,未见并发症发生。实验组在不同时间点与对照组相比较均可见新生内膜面积及厚度减少、血管腔面积及外弹力膜包绕面积增加现象 ;新生内膜中胶原含量有增生受抑现象。结论 :在球囊扩张成形术后即刻应用血管内 1 92 Ir2 0 Gy放射治疗 ,第 3天起明显抑制新生内膜形成 ,第 10天时新生内膜抑制达到高峰 ,血管发生有意义的正性重塑 ,到 2 8天时血管正性重塑更加明显 ,从而达到有效抑制动脉损伤后狭窄形成的效果。

Objective:To dynamically evaluate the effect and the safety of endovascular radiation in preventing from arterial narrowness after iliac balloon injury in pig and its mechanism. Methods:Thirteen Chinese domestic pigs (20 to 22 kg) were randomly divided into control group ( n=7 ) and radiation treatment group ( n=6 ). Angiographies and endovascular ultrasounds were made in the left iliacs, on which then ballon overstretch injury was undergone in both groups. An 192 Ir source through afterloader was positioned at the target segment in the treatment group with a dose of 20Gy. The pigs were killed at 3 rd day, 10 th day and 28 th day later respectively, the injured iliac segments were stained by hematoxylin eosin and Masson for histological and morphological study. Results:Compared with the control group, neointima area and maximal neointimal thickness were significantly reduced in endovascular radiation group [(0.03±0.01) mm 2 vs (0.08±0.04) mm 2, P <0.01 and (21.14±11.20) μm vs (43.27±13.19) μm, P<0.01) ] respectively. At 10 th day, the neointimal hyperplasia and vascular remodeling were maximally reduced in the radiation treating group. Compared with the control group, the percentage of stenosis area in the radiation treatment group was decreased (15.07% vs 46.99%, P<0.01 ) and the increase of collagen area in neointima was obviously inhibited [(42.16±23.27) vs (62.94±31.20), P<0.01 ]. At 30 th day, the percentage of stenosis area in the radiation treatment group was smaller than that in control group [(20.49±13.12) vs (59.64±25 01), P <0 01] and the increase of collagen area in neointima was further inhibited. No complications were observed among the two groups. Conclusion:Endovascular radiation can effectively reduce the neointimal formation and vascular remodeling in injuried arteries. Endovascular radiation with 192 Ir HDR afterloader is safe to animals and to operators. It may be a promising method to prevent restenosis after angioplasty.