ABSTRACT
We investigated the ability of neural crest (NC) cells to colonize hindgut, which had remained aneuronal due to bowel transection in ovo at an early stage. The fact that the bowel remained aneuronal proved that the "sacral" NC does not provide precursor cells for enteric neurons in the hindgut. HNK-1 immunostaining of aneuronal hindgut revealed cell-free, ganglionic structures at the site of the myenteric plexus and a sub-population of mesenchymal cells in the submucosa. We cocultured this particular type of aneuronal bowel with the vagal neural anlage of either quail or chick embryos on the chick chorioallantoic membrane. After 1 week coculture, it appeared that NC cell colonisation of the hindgut had taken place, although there was a difference between the quail-chick and chick-chick model. Quail NC cells had given rise to submucous plexuses and some myenteric plexuses. Chick NC cells had only colonised the submucous region. These findings indicate that the cell-free ganglionic structures hamper neural crest cell colonization in the myenteric region.
Subject(s)
Disease Models, Animal , Hirschsprung Disease , Animals , Cell Differentiation , Cell Movement , Cells, Cultured , Chick Embryo , Hirschsprung Disease/etiology , Neural Crest/cytologyABSTRACT
Based on experimental studies in mutant mouse strains, an imbalance between the rate of migration of neural crest cells and the rate of differentiation of the mesenchyme of the distal gut has been proposed as an etiological factor in Hirschsprung's disease. We studied the influence of the stage of differentiation of embryonal chick gut on the migration of neural crest cells in an in vivo culture system: the chorioallantoic membrane. Neural crest cells in cultured gut were demonstrated with antibodies directed against the HNK-1 epitope. Enteric neurons were demonstrated with neurofilament immunoreactivity. By culturing isolated gut segments of E4 embryos, we obtained aneuronal (neurofilament-negative) embryonal chick gut up to 25 days of development. In cocultures of aneuronal gut and the neural anlage (neural tube and neural crest) neural crest cell colonization was observed, even in advanced stages of differentiation. The significance of the results is discussed in terms of the etiology of Hirschsprung's disease.
Subject(s)
Digestive System/embryology , Hirschsprung Disease/etiology , Neural Crest/cytology , Animals , Cell Differentiation , Cell Movement , Chick Embryo , Digestive System/immunology , Digestive System/innervation , Disease Models, Animal , Hirschsprung Disease/embryology , Killer Cells, Natural/cytology , Killer Cells, Natural/immunology , Neural Crest/immunologyABSTRACT
Monoclonal antibodies (MAb) directed against neuron-specific epitopes are valuable tools in the diagnosis of congenital and acquired enteric nervous system anomalies. MAb raised against cytoskeleton proteins (neurofilaments) revealed a characteristic staining pattern in patients with various motility disorders of the gut. Application of MAb in the study of the development of the enteric nervous system in the chicken embryo provided new insights into the fate of migrating neural crest cells. The relationship between mesenchymal target cells in the gut and proliferating neural crest cells was studied by means of MAb raised against cell surface markers (HNK-1) in combination with characterization of the microenvironment using monoclonal antibodies raised against cell adhesion molecules (N-CAM).
