Graça D L, Bondan E F, Pereira L A, Fernandes C G, Maiorka P C
Departamento de Patologia, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil.
Arq Neuropsiquiatr. 2001 Jun;59(2-B):358-61. doi: 10.1590/s0004-282x2001000300009.
Oligodendrocytes and Schwann cells are engaged in myelin production, maintenance and repairing respectively in the central nervous system (CNS) and the peripheral nervous system (PNS). Whereas oligodendrocytes act only within the CNS, Schwann cells are able to invade the CNS in order to make new myelin sheaths around demyelinated axons. Both cells have some limitations in their activities, i.e. oligodendrocytes are post-mitotic cells and Schwann cells only get into the CNS in the absence of astrocytes. Ethidium bromide (EB) is a gliotoxic chemical that when injected locally within the CNS, induce demyelination. In the EB model of demyelination, glial cells are destroyed early after intoxication and Schwann cells are free to approach the naked central axons. In normal Wistar rats, regeneration of lost myelin sheaths can be achieved as early as thirteen days after intoxication; in Wistar rats immunosuppressed with cyclophosphamide the process is delayed and in rats administered cyclosporine it may be accelerated. Aiming the enlightening of those complex processes, all events concerning the myelinating cells in an experimental model are herein presented and discussed.
少突胶质细胞和施万细胞分别在中枢神经系统（CNS）和周围神经系统（PNS）中参与髓磷脂的产生、维持和修复。少突胶质细胞仅在中枢神经系统内发挥作用，而施万细胞能够侵入中枢神经系统，以便在脱髓鞘轴突周围形成新的髓鞘。这两种细胞的活动都存在一些局限性，即少突胶质细胞是有丝分裂后细胞，而施万细胞仅在没有星形胶质细胞的情况下进入中枢神经系统。溴化乙锭（EB）是一种对神经胶质细胞有毒的化学物质，当局部注射到中枢神经系统内时，会诱导脱髓鞘。在EB诱导的脱髓鞘模型中，中毒后早期神经胶质细胞被破坏，施万细胞可自由接近裸露的中枢轴突。在正常的Wistar大鼠中，中毒后最早在13天就可实现丢失髓鞘的再生；在用环磷酰胺免疫抑制的Wistar大鼠中，这一过程会延迟，而在给予环孢素的大鼠中，这一过程可能会加速。为了阐明这些复杂的过程，本文展示并讨论了一个实验模型中与髓鞘形成细胞有关的所有事件。
