Chakrabortty S, Tamaki N, Ehara K, Takahashi A, Ide C
Department of Neurosurgery, Kobe University School of Medicine, Japan.
Surg Neurol. 1997 Sep;48(3):246-54. doi: 10.1016/s0090-3019(96)00491-0.
In human hydrosyringomyelia and in the late stage of experimental syringomyelia, the spinal cord tissue adjacent to the syrinx is exposed to a similar pathophysiologic condition. We investigated the ultrastructural changes in the late stages of kaolin-induced syringomyelia, and in addition, we presented magnetic resonance imaging (MRI) findings of the cervicomedullary junction and syrinx, and the nature of edema in the spinal cord of this experimental model.
Syringomyelia was induced in rabbits by intracisternal injection of kaolin. MRI was performed at 6 weeks, and 6 and 12 months following injection, and the animals were killed by transcardial perfusion of formaldehyde solution and examined by transmission electron microscopy. Evans blue was injected intravenously in six rabbits, 6 weeks and 12 months following kaolin injection and was examined by confocal laser scanning microscopy.
MRI showed that the syrinx communicated with the fourth ventricle in most animals. Demyelination of varying degrees and slight edematous change were seen in the perisyrinx white matter. No extravasation of Evans blue was seen by confocal microscopy. Abundant astrocytic proliferation with a large number of glial filaments was seen at the margin of the syrinx and between the axons in the perisyringeal region. The perivascular space enlargement occurred in both the gray and white matter. The endothelial junctions appeared intact. Regenerating axons and remyelination by oligodendrocytes were seen occasionally.
The MRI confirmed the communication between the fourth ventricle and the syrinx. The ultrastructural changes were almost identical to those of the early stage syrinx, but the astrocytic proliferation was more severe, and the edema was less in the late stage. The perisyrinx edema appeared to be of the interstitial type, as in hydrocephalus. Axonal degeneration and demyelination continued with abortive attempt at regeneration and remyelination in the less edematous late stage, which might be the cellular basis for the persistence or worsening of clinical symptoms and signs in the chronic stage of syringomyelia even after surgical treatment.
在人类积水性脊髓空洞症以及实验性脊髓空洞症的晚期，空洞附近的脊髓组织会面临相似的病理生理状况。我们研究了高岭土诱导的脊髓空洞症晚期的超微结构变化，此外，还展示了该实验模型颈髓交界处和空洞的磁共振成像（MRI）结果，以及脊髓水肿的性质。
通过向兔脑池内注射高岭土诱导脊髓空洞症。在注射后6周、6个月和12个月进行MRI检查，然后通过经心脏灌注甲醛溶液处死动物，并进行透射电子显微镜检查。在高岭土注射后6周和12个月，对6只兔静脉注射伊文思蓝，并通过共聚焦激光扫描显微镜检查。
MRI显示大多数动物的空洞与第四脑室相通。在空洞周围白质可见不同程度的脱髓鞘和轻微水肿改变。共聚焦显微镜检查未见伊文思蓝外渗。在空洞边缘和空洞周围区域的轴突之间可见大量星形细胞增生及大量胶质丝。灰质和白质均出现血管周围间隙增宽。内皮连接似乎完整。偶尔可见再生轴突和少突胶质细胞进行髓鞘再生。
MRI证实了第四脑室与空洞相通。超微结构变化与早期空洞几乎相同，但晚期星形细胞增生更严重，水肿较轻。空洞周围水肿似乎为间质性水肿，如同脑积水。在水肿较轻的晚期，轴突变性和脱髓鞘仍持续存在，并伴有再生和髓鞘再生失败的尝试，这可能是脊髓空洞症慢性期即使手术治疗后临床症状和体征仍持续或恶化的细胞基础。
