Ebara Masaki, Yuki Ichiro, Murayama Yuichi, Saguchi Takayuki, Nien Yih-Lin, Vinters Harry V, Vinuela Fernando, Abe Toshiaki
Department of Neurosurgery, The Jikei University School of Medicine, Tokyo 105-8471, Japan.
Surg Neurol. 2009 Dec;72(6):620-7; discussion 627. doi: 10.1016/j.surneu.2009.04.017.
To investigate biomaterials seeking for their possible use for aneurysm treatment, in vivo screening tests using a number of potential materials are required. However, there is no established animal model that is suitable for such purpose. Some models require special preparation of tested materials for transcatheter delivery and others are inappropriate in view of their cost-effectiveness. The purpose of this study is to establish an animal model that overcomes these limitations and help us select potential materials before the preclinical evaluation.
Bilateral CCAs in a rabbit were surgically ligated, and a 2-cm segment of either a bare platinum coil or a polymeric coil (a platinum coil coated with PLGA 10/90) was implanted into each blind-ended arterial segment (n = 26). They were harvested at day 1, 7, 10, 14, or 30, respectively. Angiographic and histologic evaluations as well as quantitative analysis on the development of the organized thrombus were performed.
One day after the implantation, both platinum and PLGA coils were surrounded by immature thrombus that was induced by blood flow stagnation in the arterial segment. At day 7, minimal thrombus organization was observed around both types of materials. At postimplantation days 10 and 14, fibrocellular responses, the early findings of the thrombus organization process, were observed in both material groups. Such histologic findings were more prominent in the PLGA coil group as compared to the platinum coil group (day 10, P = .051; day 14, P = .011). Well-organized thrombus was observed in both material groups at day 30 without showing statistical difference (P = .12).
Given the cost-effectiveness, the simple material preparation process, and its feasible histologic evaluation methods, this new animal model can be useful in screening other potential biomaterials for the development of new coil devices.
为了研究可用于动脉瘤治疗的生物材料，需要使用多种潜在材料进行体内筛选试验。然而，目前尚无适用于此目的的成熟动物模型。一些模型需要对测试材料进行特殊制备以用于经导管输送，而另一些模型从成本效益角度来看并不合适。本研究的目的是建立一种克服这些局限性的动物模型，并帮助我们在临床前评估之前选择潜在材料。
通过手术结扎兔的双侧颈总动脉，并将一段2厘米长的裸铂线圈或聚合物线圈（涂有PLGA 10/90的铂线圈）植入每个盲端动脉段（n = 26）。分别在第1、7、10、14或30天收获样本。进行血管造影和组织学评估以及对有组织血栓形成的定量分析。
植入后一天，铂线圈和PLGA线圈均被动脉段血流停滞诱导形成的不成熟血栓包围。在第7天，在两种材料周围均观察到最小程度的血栓组织化。在植入后第10天和第14天，在两个材料组中均观察到纤维细胞反应，这是血栓组织化过程的早期表现。与铂线圈组相比，这种组织学发现在PLGA线圈组中更为突出（第10天，P = 0.051；第14天，P = 0.011）。在第30天，两个材料组中均观察到组织良好的血栓，且无统计学差异（P = 0.12）。
鉴于其成本效益、简单的材料制备过程及其可行的组织学评估方法，这种新的动物模型可用于筛选其他潜在的生物材料以开发新型线圈装置。
