Transfer of horseradish peroxidase from oligodendrocyte to axon in the myelinating neonatal rat optic nerve: Artefact or transcellular exchange?
Transfer of horseradish peroxidase from oligodendrocyte to axon in the myelinating neonatal rat optic nerve: Artefact or transcellular exchange?
复制标题
DOI：
10.1002/(sici)1098-1136(199608)17:4
复制
发表时间：
1996-08-01
期刊：
影响因子：
6.2
通讯作者：
Butt, AM
中科院分区：
文献类型：
--
作者：
Duncan, A;Ibrahim, M;Butt, AM
在本文中，我们令人惊讶地观察到，细胞内注射辣根过氧化物酶(HRP)到单个髓鞘少突胶质细胞也导致了HRP在该单位一些轴突的Ranvier结点的定位标记。可见HRP已从充满HRP的少突胶质细胞的结旁环转移到结节轴浆。从14日龄大鼠视神经中分离出3个充满HRP的少突胶质细胞，用连续切片电子显微镜观察到其中一个细胞所示的Ranvier结节的轴突胞浆内有HRP。在标记的结节，HRP在整个结节轴浆内呈均匀的强度。轴突标记沿结旁逐渐减少，在距结节20微米以外的相邻节间轴浆中不明显。髓鞘、结旁环和轴突在标记的结节处显示正常，与HRP充满的少突胶质细胞单位相邻的结旁环和星形胶质细胞结周突起不含HRP。周围神经束中没有细胞外HRP或组织损伤的证据，被HRP包裹的少突胶质细胞周围的轴突不含HRP。讨论了轴突标记是离子导入注射或组织制备的人工制品的可能性。这一具有挑衅性的发现并不是交换的确切证据，但证据的平衡支持了这样一种可能性，即在标记的少突胶质细胞和单位内的一些轴突之间存在着副阳极处HRP的跨细胞交换。HRP转移到轴突的罕见提示它可能是一过性的或不稳定的事件。目前尚不清楚少突胶质细胞到轴突的大分子交换是否具有真正的生理和/或病理意义。(C)1996年Wiley-Liss，Inc.
In this paper we make the surprising observation that intracellular injection of horseradish peroxidase (HRP) into a single myelinating oligodendrocyte also resulted in localised HRP labelling at the nodes of Ranvier of some axons of the unit. It appeared that HRP had been transferred to the nodal axoplasm from the paranodal loops of the HRP-filled oligodendrocyte. Three HRP-filled oligodendrocytes from isolated optic nerves of 14-day-old rats were analysed by serial section electron microscopy, and HRP was observed in the axonal cytoplasm at three of the nodes of Ranvier delineated by one of the cells. At labelled nodes, HRP was of a uniform intensity throughout the nodal axoplasm. Axonal labelling gradually diminished along the paranodal regions and was not evident in the contiguous internodal axoplasm beyond 20 mu m from the node. The myelin sheaths, paranodal loops, and axons appeared normal at labelled nodes, and the paranodal loops and astrocyte perinodal processes adjacent to those of the HRP-filled oligodendrocyte unit did not contain HRP. There was no evidence of extracellular HRP or tissue damage in the surrounding neuropil, and axons neighbouring those enwrapped by the HRP-filled oligodendrocyte did not contain HRP. The possibility that axonal labelling was an artefact of either iontophoretic injection or tissue preparation is discussed. This provocative finding is not definite proof of exchange, but the balance of evidence supports the possibility that there was transcellular exchange of HRP at paranodes between the labelled oligodendrocyte and some of the axons in the unit. The rarity of HRP transfer to axons suggests that it may be a transient or labile event. It is not clear whether oligodendrocyte to axon macromolecular exchange has real physiological and/or pathological significance. (C) 1996 Wiley-Liss, Inc.