Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
J Vasc Interv Radiol. 2010 Dec;21(12):1884-90. doi: 10.1016/j.jvir.2010.07.026. Epub 2010 Oct 27.
To evaluate the feasibility of metallic stent placement and the formation of granulation tissue caused by stent placement in a rat urethral model.
A bare self-expanding metallic stent was inserted in the urethra under fluoroscopic guidance in 20 male Sprague-Dawley rats. Ten rats were euthanized at 4 weeks (group A), and the other 10 were euthanized at 8 weeks after stent placement (group B). Stenosis diameter, number of epithelial layers, degree of inflammatory cell infiltration, thickness of submucosal fibrosis, and percentage of granulation tissue area were assessed.
Stent placement was technically successful in all rats. Urethrograms showed perforation in three rats, partial migration in three, and stone formation in four. Granulation tissue formation was observed in all rats at the stent-implanted urethra, and the average percentage of granulation tissue area accounted for 41% and 45% of the original urethral lumen area in groups A and B, respectively. Urethrograms and urethral specimens showed significantly less stenosis diameter, less thickness of submucosal fibrosis, and lower percentage of granulation tissue area in the proximal urethra than in the distal urethra in both groups (P < .05). Histologic results demonstrated significantly fewer epithelial layers in group B compared with group A (P = .028).
Placement of a self-expandable metallic stent proved to be feasible in the rat urethra and an efficient approach to stimulate granulation tissue formation as a potential model for reproducing the mechanisms of restenosis.
评估在大鼠尿道模型中放置金属支架和由支架放置引起的肉芽组织形成的可行性。
在荧光透视引导下，将裸自膨式金属支架插入 20 只雄性 Sprague-Dawley 大鼠的尿道中。10 只大鼠在 4 周（A 组）时处死，另外 10 只大鼠在支架放置 8 周后处死（B 组）。评估狭窄直径、上皮层数、炎症细胞浸润程度、黏膜下纤维化厚度和肉芽组织面积百分比。
所有大鼠的支架放置技术均成功。尿道造影显示 3 只大鼠穿孔，3 只大鼠部分迁移，4 只大鼠结石形成。所有大鼠在支架植入的尿道处均观察到肉芽组织形成，A、B 组的肉芽组织面积百分比分别占原始尿道腔面积的 41%和 45%。尿道造影和尿道标本显示，A、B 两组近端尿道的狭窄直径、黏膜下纤维化厚度和肉芽组织面积百分比明显小于远端尿道（P <.05）。组织学结果显示，B 组的上皮层数明显少于 A 组（P =.028）。
在大鼠尿道中放置自膨式金属支架是可行的，并且是一种刺激肉芽组织形成的有效方法，可作为复制再狭窄机制的潜在模型。
