An orthotopic murine model of human spinal metastasis: histological and functional correlations.
An orthotopic murine model of human spinal metastasis: histological and functional correlations.
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人脊柱转移的原位鼠模型：组织学和功能相关。
DOI：
10.3171/2009.2.spine08391
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发表时间：
2009-06
期刊：
影响因子：
--
通讯作者：
Rhines LD
中科院分区：
文献类型：
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作者：
Tatsui CE;Lang FF;Gumin J;Suki D;Shinojima N;Rhines LD
目前还没有可重复的人类脊柱转移动物模型可以对人类疾病进行实验室研究。因此，作者试图利用人肺癌细胞系开发脊柱转移的原位模型，并将神经功能衰退与肿瘤生长联系起来。为了建立脊柱转移模型，作者采用经腹膜手术方法，通过钻孔将 PC-14 肺部肿瘤植入裸鼠的 L-3 椎体内。每天使用经过验证的半定量 Basso-Beattie-Bresnahan (BBB) 量表对 24 只动物的运动功能进行评分。第二组 26 只动物（每个时间点 6 或 7 只）在特定时间被处死，脊柱被移除、切片和染色。通过确定组织学切片上神经元件面积与椎管面积的比率（神经/椎管比率）来定量分析椎管损害。评估了 BBB 评分与肿瘤生长的组织学评估之间的相关性。肺癌异种移植物在所有接受功能评估的动物（24只小鼠）中按照可靠且可重复的时间进程生长，截瘫发生在肿瘤植入后中位间隔30天（95% CI 28.1-31.9天）。重要的是，该分析根据 BBB 分数的组成部分定义了 4 个关键里程碑；这些在所有动物中都观察到，是一致的，并且与肿瘤的组织学进展相关。从第 1 天到第 14 天，平均 BBB 分数从 21 下降到 19。动物从正常的尾巴向上行走发展到尾巴不断接触地面的行走（里程碑 1）。拖尾的中位时间为 12 天 (95% CI 10.8–13.2)。第14天的组织学研究表明，肿瘤已从部分VB浸润进展为完全VB浸润，神经元件最初受压，硬膜外肿瘤延伸至邻近水平（平均神经/管比率0.32±0.05，7只小鼠）。从第 15 天到第 20/21 天（左/右腿），平均 BBB 评分从 19 下降到 14。动物表现出步态恶化，出现背侧迈步（里程碑 2）。左后肢的背侧迈步中位时间为 21 天（95% CI 19.4-22.6），右后肢为 23 天（95% CI 20.6-25.4）。第21天的组织学研究表明，神经元件受压的严重程度增加，肿瘤延伸至邻近的硬膜外和骨水平（平均神经/管比率0.19±0.05，6只小鼠）。从第 22 天到第 26/27 天（左/右腿），平均 BBB 评分从 14 下降到 8。动物行走逐渐困难，直至仅表现出后肢的扫动运动（里程碑 3）。左后肢和右后肢的中位时间分别为 26 天 (95% CI 23.6–28.4) 和 28 天 (95% CI 27.1–28.9)。第 28 天的组织学研究显示椎管进行性闭塞（平均神经/椎管比率 0.09 ± 0.01，7 只小鼠）。从第 29 天到第 36 天，动物逐渐瘫痪（里程碑 4）。左后肢和右后肢的中位麻痹时间分别为 29 天（95% CI 27.6-30.4）和 30 天（95% CI 28.1-31.9）。作者开发了人类脊柱转移的原位小鼠模型，其中神经功能衰退与肿瘤进展的严重程度可重复相关。虽然该模型是针对肺癌开发的，但可以扩展到研究其他类型的转移性或原发性脊柱肿瘤。最终，这将允许测试针对特定肿瘤类型的靶向疗法。
There is currently no reproducible animal model of human spinal metastasis that allows for laboratory study of the human disease. Consequently, the authors sought to develop an orthotopic model of spinal metastasis by using a human lung cancer cell line, and to correlate neurological decline with tumor growth. To establish a model of spinal metastasis, the authors used a transperitoneal surgical approach to implant PC-14 lung tumors into the L-3 vertebral body of nude mice via a drill hole. In 24 animals, motor function was scored daily by using the validated semiquantitative Basso-Beattie-Bresnahan (BBB) scale. A second group of 26 animals (6 or 7 per time point) were sacrificed at specific times, and the spines were removed, sectioned, and stained. Canal compromise was analyzed quantitatively by determining the ratio of the area of the neural elements to the area of the spinal canal on histological sections (neural/canal ratio). Correlations between BBB score and histological evaluation of tumor growth were assessed. Lung cancer xenografts grew in all animals undergoing functional evaluation (24 mice) according to a reliable and reproducible time course, with paraplegia occurring at a median interval of 30 days following tumor implantation (95% CI 28.1–31.9 days). Importantly, the analysis defined 4 key milestones based on components of the BBB score; these were observed in all animals, were consistent, and correlated with histological progression of tumor. From Days 1 to 14, the mean BBB score declined from 21 to 19. The animals progressed from normal walking with the tail up to walking with the tail constantly touching the ground (milestone 1). The median time to tail dragging was 12 days (95% CI 10.8–13.2). Histological studies on Day 14 demonstrated that tumor had progressed from partial to complete VB infiltration, with initial compression of the neural elements and epidural tumor extension to adjacent levels (mean neural/canal ratio 0.32 ± 0.05, 7 mice). From Days 15 to 20/21 (left/right leg), the mean BBB score declined from 19 to 14. Animals showed gait deterioration, with the development of dorsal stepping (milestone 2). The median time to dorsal stepping was 21 days (95% CI 19.4–22.6) in the left hindlimb and 23 days (95% CI 20.6–25.4) in the right hindlimb. Histological studies on Day 21 demonstrated an increase in the severity of the neural element compression, with tumor extending to adjacent epidural and osseous levels (mean neural/canal ratio 0.19 ± 0.05, 6 mice). From Days 22 to 26/27 (left/right leg), the mean BBB score declined from 14 to 8. Animals had progressive difficulty ambulating, to the point where they showed only sweeping movements of the hindlimb (milestone 3). The median time to hindlimb sweeping was 26 days (95% CI 23.6–28.4) and 28 days (95% CI 27.1–28.9) in the left and right hindlimbs, respectively. Histological studies on Day 28 revealed progressive obliteration of the spinal canal (mean neural/canal ratio 0.09 ± 0.01, 7 mice). From Days 29 to 36, the animals progressed to paralysis (milestone 4). The median time to paralysis was 29 days (95% CI 27.6–30.4) and 30 days (95% CI 28.1–31.9) in the left and right hindlimbs, respectively. The authors have developed an orthotopic murine model of human spinal metastasis in which neurological decline reproducibly correlates with severity of tumor progression. Although developed for lung cancer, this model can be expanded to study other types of metastatic or primary spinal tumors. Ultimately, this will allow testing of targeted therapies against specific tumor types.