Abstract: Objective To investigate the long - term stability of syringomyelia (SM) rat model constructed by epidural compression. Methods A total of 35 Sprague - Danley (SD) rats were randomly divided into sham surgery group (n = 9), short-term group (n = 6) and long-term group (n = 20). The central spinal canal was blocked by epidural compression to induce SM in rats. Basso - Beattie - Bresnahan score (BBB) was used to evaluate lower limb motor function before surgery and at 3, 6, 9 and 12 months after surgery. The morphological changes of SM were evaluated by MRI and HE staining at 2 and 12 months after surgery. Results At 2 and 12 months after surgery, MRI showed 80% (16/20) and 85% (17/20) rats in long - term group had SM. Compared with 2 months after surgery, the ratio of the maximum cavity diameter to the diameter of spinal cord plane (Z = - 3.518,P = 0.000) and the ratio of the maximum cavity area to the area of spinal cord plane (Z = - 3.464,P = 0.001) increased in long-term group at 12 months after surgery. At 2 and 12 months after surgery, the morphology of the spinal cord was normal and there was no cavity in sham surgery group, while the spinal cord cavity was observed in the short-term group at 2 months after surgery. At 12 months after surgery, the cavity area of the long -term group was not only larger than that of the short-term group, but also involved more vertebral segments. There was no significant difference in BBB score between sham surgery group and long - term group at different time points before and after surgery (P > 0.05, for all). Conclusions The rat model of SM constructed by epidural compression has high positive rate, good long-term stability, and does not affect the motor function of rats.

Key words: Syringomyelia, Epidural space, Magnetic resonance imaging, Pathology, Disease models, animal

摘要： 目的 探讨硬脊膜外压迫法构建脊髓空洞症大鼠模型的长期稳定性。方法 共35只Sprague-Danley大鼠随机分为假手术组（9只）、短期实验组（6只）和长期实验组（20只），硬脊膜外压迫法阻塞脊髓中央管以诱导脊髓空洞形成，分别于术前及术后3、6、9和12个月采用Basso-Beattie-Bresnahan评分（BBB）评估后肢运动功能；术后2和12个月行MRI检查和HE染色评估脊髓空洞形态学改变。结果 术后2和12个月时，MRI检查显示长期实验组分别有80%（16/20）和85%（17/20）大鼠出现脊髓空洞；与术后2个月相比，长期实验组大鼠术后12个月时最大空洞前后径与其所在脊髓平面前后径比值（Z=- 3.518，P=0.000）和最大空洞面积与其所在脊髓平面面积比值（Z=- 3.464，P=0.001）均增加；假手术组大鼠术后2和12个月时脊髓形态正常、无空洞形成，术后2个月时短期实验组可见脊髓空洞形成，术后12个月时长期实验组空洞面积不仅大于短期实验组且累及更多椎体节段；假手术组和长期实验组大鼠手术前后不同时间点BBB评分差异无统计学意义（均P > 0.05）。结论 硬脊膜外压迫法构建脊髓空洞症大鼠模型阳性率高，具有较好的长期稳定性，且不影响运动功能。

关键词: 脊髓空洞症, 硬膜外隙, 磁共振成像, 病理学, 疾病模型, 动物