Insulin-like growth factor-I promotes myelination of peripheral sensory axons.
J Neuropathol Exp Neurol
; 59(7): 575-84, 2000 Jul.
Article
en En
| MEDLINE
| ID: mdl-10901228
ABSTRACT
Insulin-like growth factor-I (IGF-I) in vivo or in the presence of other permissive factors can promote myelination in the central nervous system. In the current study, we examine the role of IGF-I in the myelination of peripheral nerves. In rat cocultures of dorsal root ganglia (DRG) and Schwann cells (SC) grown in serum- and insulin-free defined medium, IGF-I induces a dose dependent upregulation in myelin proteins such as P0, corresponding to maximal SC ensheathment. Furthermore, IGF-I is essential in promoting a dose-dependent, long-term myelination of DRG sensory axons. In the absence of IGF-I, axons and SC survive, but fail to myelinate. In the presence of 10 nM IGF-I, 59% of axons are myelinated at 21 days, whereas in the absence of IGF-I myelination fails to occur. Maximum SC ensheathment occurs 48 hours after addition of IGF-I. If IGF-I is withdrawn at 48 hours, axon segregation by SC persists, however, most axons and SC do not exhibit a one-to-one relationship and little myelination is observed. IGF-I is important in myelination and is critical not only for initial SC ensheathment of the axon and upregulation of myelin proteins, but also for sustained myelination. Furthermore, IGF-I associated axonal size is not the sole determinant for myelination.
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Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Células de Schwann
/
Factor I del Crecimiento Similar a la Insulina
/
Ganglios Espinales
/
Vaina de Mielina
/
Neuronas Aferentes
Límite:
Animals
Idioma:
En
Revista:
J Neuropathol Exp Neurol
Año:
2000
Tipo del documento:
Article
País de afiliación:
Estados Unidos