Bouslama-Oueghlani Lamia, Wehrlé Rosine, Sotelo Constantino, Dusart Isabelle
Institut National de la Santé et de la Recherche Médicale U106, Hôpital de la Salpêtrière, 75651 Paris, France.
J Neurosci. 2003 Sep 10;23(23):8318-29. doi: 10.1523/JNEUROSCI.23-23-08318.2003.
Axonal regeneration in the mammalian CNS is a property of immature neurons that is lost during development. Using organotypic culture of cerebellum, we have shown that in vitro Purkinje cells lose their regenerative capacity in parallel with the process of myelination. We have investigated whether myelination is involved in the age-dependent loss of regeneration of these neurons. By applying a high dose of bromodeoxyuridine in the culture medium of newborn cerebellar slices during the first 3 d in vitro, we have succeeded in obtaining cultures with oligodendrocyte depletion, together with a lack of ameboid microglia and enhancement of Purkinje cell survival. These cultures, after 14 d in vitro, are completely devoid of myelin. We have compared the ability of Purkinje cells to regenerate their axons in the presence or absence of myelin. Purkinje cells in cerebellar explants taken at birth, treated with bromodeoxyuridine and axotomized after 7 d in vitro, survive better than similar neurons in untreated cultures. However, despite the lack of myelin and the enhanced survival, Purkinje cells do not regenerate, whereas they do regenerate when the axotomy is done at postnatal day 0. Thus, the Purkinje cell developmental switch from axonal regeneration to lack of regeneration does not appear to be regulated by myelin.
哺乳动物中枢神经系统中的轴突再生是未成熟神经元的一种特性，在发育过程中会丧失。利用小脑的器官型培养，我们已经表明，体外培养的浦肯野细胞在髓鞘形成过程中同时丧失其再生能力。我们研究了髓鞘形成是否与这些神经元再生能力的年龄依赖性丧失有关。通过在体外培养的头3天，在新生小脑切片的培养基中加入高剂量的溴脱氧尿苷，我们成功获得了少突胶质细胞缺失、无阿米巴样小胶质细胞且浦肯野细胞存活率提高的培养物。这些培养物在体外培养14天后完全没有髓鞘。我们比较了有髓鞘和无髓鞘情况下浦肯野细胞再生轴突的能力。出生时取材的小脑外植体中的浦肯野细胞，用溴脱氧尿苷处理并在体外培养7天后进行轴突切断，其存活情况比未处理培养物中的类似神经元更好。然而，尽管缺乏髓鞘且存活率提高，浦肯野细胞仍不能再生，而在出生后第0天进行轴突切断时它们则能够再生。因此，浦肯野细胞从轴突再生到丧失再生能力的发育转变似乎不受髓鞘的调节。
