血管内近距离照射对兔髂动脉术后中膜平滑肌细胞凋亡的影响

目的观察血管内近距离照射（BT）对血管成形术后动脉中膜平滑肌细胞（SMC）凋亡的影响，并观察其量效关系，初步探讨其防治再狭窄的可能机制。方法24只大耳白兔随机分为3组，选择一侧行髂动脉血管成形术并分别给予9．1Gy、21．8Gy和33．4Gy^32 P液体球囊血管内照射治疗，对侧作为对照。术后5周，重复血管造影观察靶血管再狭窄程度，应用三磷酸脱氧尿嘧啶缺口末端标记法（TUNEL法）检测中膜平滑肌细胞凋亡的情况。结果血管造影显示9．1Gy组狭窄与对照血管段无明显差异（P〉0．05）；21．8Gy组为仅轻度狭窄（P〈0．05）；33．4Gy组为重度狭窄（P〈0．05）。TUNEL阳性率在21．8Gy组和33．4Gy组均高于自身对照组（P〈0．01）。3个照射剂量组间，21．8Gy组作用最明显（P〈0．01）。结论^32P放射性液体球囊血管内照射治疗在一定剂量范围内可防止血管成形术后再狭窄的形成，促进血管中膜平滑肌细胞凋亡可能是其作用机制之一。

Effects of Endovascular Brachytherapy on the Apoptosis of Vascular Medial Smooth Muscle Cells in Rabbits after Iliac Artery Ballon-overstretch Injury

Objective To observe the effects of endovascular brachytherapy on the apoptosis of vascular medial smooth muscle cell ( SMC) and the dose-effect relation . To discuss the possible mechanisms of radiation in the prevention of vascular restenosis (RS) in rabbits after iliac artery balloon-overstretch injury. Methods Twenty-four rabbits were randomly divided into four groups. One sides iliac artery were given a radiation dose of 9.1, 21. 8 and 33.4Gy 32P respectively compared with the other sides. Rabbits were killed on the 5th week after operation. Apoptosis was examined using terminal deoxynucleotidyl transferase-media-ted deoxyuridine triphosphate nick-end labeling (TUNEL). Results Compared with the control group, the degree of restenosis was not statistical difference in 9. 1 Gy group and was slight in 21. 8 Gy group,was high in 33.4 Gy group. The apoptosis rate in 21. 8 Gy and 33.4 Gy groups was higher than that in control group. The effect was much more evident in 21. 8 Gy group. Conclusion Endovascular brachytherapy with 32P filled ballon catheter system could prevent restenosis after angioplasty . Inducing SMC apoptosis may contribute to the preventing of restenosis.