颈脊髓渐进压迫损伤中雌二醇调节神经血管单元结构重塑的影像病理机制

In early stage of degenerated cervical myelopathy (DCM), the compensatory reconstruction of neurovascular unit (NVU) can be induced by intramedullary ischemia. However, in the decompensated stage, the spinal cord injury progress rapidly, the detailed mechanism is only partially understood. The decompensated DCM, whose pathological course can be irreversible due to a lack of monitoring method, has a high disability rate. Previously, we use diffusion tensor imaging (DTI) to evaluate changes in microcirculation and quantify spinal cord injury; we tried to use diffusion kurtosis imaging (DKI) as a quantitative evaluation tool to assess the expression of vascular endothelial growth factor (VEGF); and we also found that estradiol, previously used as a central nervous system protector, can upregulate the expression of hypoxia-inducible factor 1α (HIF-1α) and matrix metalloproteinase-2 (MMP-2) and induce micro angiogenesis in NVU, but the mechanism of action had not been elucidated. We assume that estradiol can upregulate MMP-2 expression via targeting HIF-1α and therefore promote reconstruction of NVU, we also assume that DKI can be used as a quantitative tool in evaluating the change of function and structure in NVU. With the help of gradually compressive cervical spinal cord injury goat model we established previously, our study aim to confirm our assumption on imaging, animal and organ level, and multidisciplinary techniques such as DKI, transmission electron microscopy, tissue culture of spinal cord and molecular biology were applied. The development of this project will provide theoretical and experimental basis in pathomechanism, target therapy and dynamic monitoring of DCM.

退变性颈脊髓病（DCM）早期髓内缺血缺氧可诱发微循环结构神经血管单元（NVU）的代偿重塑，进入失代偿期后损伤多迅速进展，因缺乏精确监测手段常造成延误诊治，致伤致残率高。我们前期通过磁共振弥散张量成像DTI评估微循环变化从而量化颈髓损伤，探索弥散峰度成像DKI定量血管内皮生长因子的表达水平，并发现中枢神经保护因子雌二醇可上调缺氧诱导因子HIF-1α和基质金属蛋白酶MMP-2表达进而促进NVU微血管再生，但影像病理学基础和分子机制尚不明确。本课题将在前期的山羊颈髓渐进压迫损伤模型基础上，综合应用DKI成像、透射电镜、分子生物学、脊髓薄片器官型培养等多学科技术，探讨DKI实时定量评估NVU结构变化中的病理学特征，并从动物和器官水平探索雌二醇通过HIF-1α通路调控MMP-2表达进而促进NVU结构重塑的可能机制。研究结果将为阐明DCM病理机制、指导干预靶点选择及病程动态监测提供理论和实验依据。

退变性颈脊髓病（DCM）早期髓内缺血缺氧可诱发微循环结构神经血管单元（NVU）的代偿重塑，进入失代偿期后损伤多迅速进展，因缺乏精确监测手段常造成延误诊治，致伤致残率高。本研究探索了褪黑素对脊髓损伤的作用及IGFBP3在脊髓损伤中的作用机制，基于生物信息学分析探讨了circRNA在脊髓损伤中的表达差异，利用String系统构建异常表达的mRNA介导的蛋白-蛋白相互作用网络，并通过实验研究circRNA- miRNA轴在脊髓损伤中的结构和潜在功能。研究结果显示：脊髓损伤大鼠IGFBP3表达明显下调，褪黑素显著提高IGFBP3水平。褪黑激素改善了大鼠的运动功能，减少了神经元损伤，改善了大鼠的微循环。而下调IGFBP3则明显保留了上述作用。同时，在缺氧条件下，脊髓损伤大鼠脊髓组织和离体周细胞中IGFBP3和Ang1的表达均显著下调，而MMP-2、VEGF和ICAM-1的蛋白表达均显著上调，褪黑激素显著抑制这些变化。在脊髓损伤样本中共有4690个mRNA, 17个miRNA和3928个circRNA被鉴定为差异表达。我们最终选择了排名前两位的circ_006573和circ_016395进行初步分析。在体外，我们证明了circ_006573和circ_016395的环状特征。过表达circ_006573极大地削弱了RAOEC细胞的活力和迁移能力，而过表达circ_016395则没有诱导上述作用。miR-376b-3p处理后，circ_006573对RAOEC细胞生物学行为的调控被解除。同时，miR-376b-3p模拟治疗逆转过表达circ_006573诱导RAOEC细胞Cebpb、IL-18和Plscr1的表达变化。体内研究进一步表明，circ_006573 shRNA处理改善了SCI大鼠的病理表现，改善了运动功能。此外，circ_006573 shRNA处理后脊髓组织中CD31、CD34和VEGF-A的表达均显著升高，提示circ_006573可能参与了脊髓损伤后的血管再生和功能修复。本研究为脊髓损伤病理机制及脊髓修复提供了可能的治疗方向，具有重要的科学意义。