Substrate-dependent migration of myelin-associated glycoprotein immunoreactive cells in cultured explants of dorsal root ganglia from chick embryos

The aim of this study was to investigate the influence of collagen or polyornithine substrates on cell migration in explant cultures of dorsal root ganglia (DRG) by means of light microscopy and immunocytochemistry. Myelin-associated glycoprotein (MAG) immunoreactivity was used to characterize the subpopulation of small B ganglion cells, whereas neuron-specific enolase (NSE) immunoreactivity acted as a general neuronal cell marker. After a few days in culture, DRG explants grown on collagen substrate showed a flattened shape consisting of a core surrounded by a crown of neurites, which were mixed up with migrating cells of different types. These migrating cells were immunostained for both MAG and NSE and were observed after 7 days in the vicinity of the explant core, then after 14 days also at a distance from the explant core. In contrast, even after 14 days in culture, explants grown on polyornithine substrate maintained a globular shape. The MAG-positive ganglion cells were confined to the explant core and no cell migration was observed on this type of substrate. MAG immunoprecipitates located at the ganglion cell surface were observed in explants cultured on polyornithine, but rarely on collagen substrate. In conclusion, it is suggested that this pattern of intracellular distribution of MAG immunoreactive material could reflect interactions between cell surface and extracellular matrix, and could condition the migratory ability of small ganglion cells.