de Vicente J C, Cabo R, Ciriaco E, Laurà R, Naves F J, Silos-Santiago I, Vega J A
Departamentos de Cirugía y Especialidades Médico-Quirúrgicas, Escuela de Estomatología, Oviedo, Spain
Ann Anat. 2002 Jan;184(1):85-92. doi: 10.1016/S0940-9602(02)80041-3.
Glial cell line-derived neurotrophic factor promotes the survival of multiple neuron types in the central and peripheral nervous system. Moreover, it plays a key role in the development of the enteric nervous system and in the kidney organogenesis. Glial cell line-derived neurotrophic factor and their receptors are expressed in the developing tooth as well as in the trigeminal ganglion. However, the precise role of this growth factor in tooth morphogenesis and cell differentiation, or in the development of trigeminal ganglion cells, is still elusive. Using structural and ultrastructural techniques we analyzed in detail the first molar tooth germ of glial cell line-derived neurotrophic factor deficient mice as well as the neuronal density in trigeminal ganglion. The length and width of first molar tooth germ in knockout deficient animals showed no differences in the knockout animals in comparison with age-matched heterozygous or wild-type littermates. Nevertheless, in mice lacking glial cell line-derived neurotrophic factor, both ameloblasts and odontoblasts failed to fully develop and differentiate, and the enamel matrix and predentin layers were absent. On the other hand, the number of trigeminal sensory neurons and the structure of the nerves supplying first molar tooth germ were largely normal. Present results suggest a new non-neuronal role for glial cell line-derived neurotrophic factor in tooth development. Glial cell line-derived neurotrophic factor seems not to be involved in tooth initiation and morphogenesis, whereas it seems essential for cytodifferentiation. Conversely, neither development of trigeminal neuron nor nerve fibers supplying teeth are directly dependent on glial cell line-derived neutrophic factor.
胶质细胞系源性神经营养因子可促进中枢和外周神经系统中多种神经元类型的存活。此外，它在肠神经系统的发育和肾脏器官发生过程中发挥关键作用。胶质细胞系源性神经营养因子及其受体在发育中的牙齿以及三叉神经节中均有表达。然而，这种生长因子在牙齿形态发生和细胞分化，或在三叉神经节细胞发育中的精确作用仍不清楚。我们使用结构和超微结构技术，详细分析了胶质细胞系源性神经营养因子缺陷小鼠的第一磨牙牙胚以及三叉神经节中的神经元密度。与年龄匹配的杂合子或野生型同窝小鼠相比，基因敲除缺陷动物的第一磨牙牙胚的长度和宽度没有差异。然而，在缺乏胶质细胞系源性神经营养因子的小鼠中，成釉细胞和成牙本质细胞均未能充分发育和分化，且釉质基质和前期牙本质层缺失。另一方面，三叉神经感觉神经元的数量以及供应第一磨牙牙胚的神经结构基本正常。目前的结果表明，胶质细胞系源性神经营养因子在牙齿发育中具有一种新的非神经元作用。胶质细胞系源性神经营养因子似乎不参与牙齿的起始和形态发生，而对细胞分化似乎至关重要。相反，三叉神经元的发育和供应牙齿的神经纤维均不直接依赖于胶质细胞系源性神经营养因子。
