Department of Physiology, Yonsei University College of Medicine, Seoul 03722, Republic of Korea.
Inhalation Toxicology Research Center, Korea Institute of Toxicology, Jeonbuk 56212, Republic of Korea.
Neurosci Res. 2019 Dec;149:14-21. doi: 10.1016/j.neures.2019.01.007. Epub 2019 Jan 24.
Manganese-enhanced magnetic resonance imaging (MEMRI) is based on neuronal activity-dependent manganese uptake, and provides information about nervous system function. However, systematic studies of pain processing using MEMRI are rare, and few investigations of pain using MEMRI have been performed in the spinal cord. Herein, we investigated the pain dependence of manganese ions administered in the rat spinal cord. MnCl was administered into the spinal cord via an intrathecal catheter before formalin injection into the right hind paw (50 μL of 5% formalin). The duration of flinching behavior was recorded and analyzed to measure formalin-induced pain. After the behavioral test, rats were sacrificed with an overdose of urethane (50 mg/kg), and spine samples were extracted and post-fixed in 4% paraformaldehyde solution. The samples were stored in 30% sucrose until molecular resonance (MR) scanning was performed. In axial Mn enhancement images of the spinal cord, Mn levels were found to be significantly elevated on the ipsilateral side of the spinal cord in formalin-injected rats. To confirm pain-dependent Mn enhancement in the spinal cord, c-Fos expression was analyzed, and was found to be increased in the formalin-injected rats. These results indicate that MEMRI is useful for functional analysis of the spinal cord under pain conditions. The gray matter appears to be the focus of intense paramagnetic signals. MEMRI may provide an effective technique for visualizing activity-dependent patterns in the spinal cord.
锰增强磁共振成像（MEMRI）基于神经元活动依赖性锰摄取，并提供有关神经系统功能的信息。然而，使用 MEMRI 进行系统性疼痛处理的研究很少，并且使用 MEMRI 进行的脊髓疼痛研究也很少。在此，我们研究了在大鼠脊髓中给予锰离子的疼痛依赖性。在右后爪（50μL 5％甲醛）注射甲醛之前，通过鞘内导管将 MnCl 给予脊髓。记录并分析畏缩行为的持续时间，以测量甲醛引起的疼痛。行为测试后，用过量的氨基甲酸乙酯（50mg/kg）处死大鼠，并提取脊柱样本，然后在 4％多聚甲醛溶液中固定。将样品储存在 30％蔗糖中，直到进行分子共振（MR）扫描。在脊髓的轴向 Mn 增强图像中，发现甲醛注射大鼠脊髓的同侧侧方 Mn 水平显着升高。为了确认脊髓中的疼痛依赖性 Mn 增强，分析了 c-Fos 表达，发现甲醛注射大鼠的 c-Fos 表达增加。这些结果表明，MEMRI 可用于在疼痛条件下对脊髓进行功能分析。灰质似乎是强顺磁信号的焦点。MEMRI 可能为可视化脊髓中活动依赖性模式提供一种有效技术。
