Loss of neuronal projections in the dystrophin-deficient mdx mouse is not progressive

Lack of dystrophin is known to reduce several cerebral fiber systems. To investigate if the loss of fibers is progressive, we analyzed projections of the trigeminal sensory system to the red nucleus in 3, 6, and 12 month old dystrophin-deficient mdx mice. the retrograde tracer fluorogold was injected in the magnocellular part of the red nucleus, and the number of labeled neurons in the oral part of the spinal trigeminal nucleus (Sp5O) was counted. we found that the number of labeled Sp5O neurons was reduced by 50% in mdx mice compared to age-matched control mice. the number of labeled Sp5O neurons did not change significantly between 3 and 12 months neither in mdx nor in control mice. in addition, the number of labeled neurons in the interstitial system of the trigeminal nerve was reduced by 43% in mdx mice. We conclude that fiber loss did not continue beyond the age of 3 months. Our data suggest that lack of full-length dystrophin impairs neuronal migration or axonal outgrowth, or increases neuronal death during fetal or early life. (c) 2008 Elsevier B.V. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Universidade Federal de São Paulo, Dept Histol, BR-04023062 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Pharmacol, BR-04023062 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Physiol, BR-04023062 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Histol, BR-04023062 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Pharmacol, BR-04023062 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Physiol, BR-04023062 São Paulo, BrazilFAPESP: 99/06625-3Web of Scienc