Ultrastructure of the cerebrospinal fluid outflow along the optic nerve into the lymphatic system
Ultrastructure of the cerebrospinal fluid outflow along the optic nerve into the lymphatic system
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DOI：
10.1007/s00381-004-1040-1
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发表时间：
2005-02-01
影响因子：
1.4
通讯作者：
Brinker, T
中科院分区：
文献类型：
--
作者：
Lüdemann, W;von Rautenfeld, DB;Brinker, T
目的：比较视神经远端和近端神经周围脑膜层的超微结构，以解释脑脊液自发性流出眼眶的原因。方法：对10只猫进行灌流固定，去除眶内容物，进行透射和扫描电子显微镜观察。在5只动物中，在灌流固定之前，在低颅压的情况下进行60min的脑池注射造影剂。结果：在注射造影剂的动物中，可以显示造影剂从蛛网膜下腔(SAS)渗入眼眶的视神经鞘(ONS)远端部分，并在结膜淋巴管中发现。电子显微镜显示ONS远端神经上皮层明显变薄，有些仅由一层组成。远端可见神经上皮覆盖层中的孔状开口。在国家统计局的远端，对SA的挖掘要多得多。挖掘到达神经上皮层。在ONS的远端，细胞内和细胞外的细丝数量较多。ONS远端和近端的硬脑膜厚度无明显差异。结果表明，在ONS的远侧部分存在蛛网膜窗区。其特点是有一层连续但较薄的神经上皮屏障层，几乎没有孔状开口。结论：远端和近端ONS的主要区别是神经上皮屏障层变薄，细胞间细丝和孔状开口数量增加。这些发现解释了沿着视神经的淋巴脑脊液流出途径。
Object: To explain the spontaneous CSF outflow into the orbit, the ultrastructure of the perineural meningeal layers at the distal and the proximal portions of the optic nerve were compared. Methods: Ten cats were perfusion fixated and the orbital content removed for transmission and scanning electron microscopy. In five animals a 60-min cisternal infusion of contrast medium at low intracranial pressure was performed before perfusion fixation. Results: In the contrast-infused animals it was possible to demonstrate the leakage of contrast medium in the distal portion of the optic nerve sheath (ONS) from the subarachnoid space (SAS) into the orbit and find it in the conjunctival lymphatics. Electron microscopy revealed that in the distal portion of the ONS the neurothelial layers are significantly thinner, some consisting of only one layer. Pore-like openings in the neurothelial covering are seen in the distal portion. Excavations of the SAS are far more numerous in the distal portion of the ONS. The excavations reach the neurothelial layer. Intracellular and extracellular filaments are more numerous in the distal portion of the ONS. There is no significant difference in the dura mater between the distal and proximal ONS. The results show the existence of an arachnoid window area in the distal portion of the ONS. It is characterised by a continuous, but thinned neurothelial barrier layer, with few pore-like openings. Conclusions: The main differences between distal and proximal ONS are a thinned neurothelial barrier layer and an increased number of intercellular filaments and pore-like openings. The findings explain the lymphatic CSF outflow pathway along the optic nerve.