Study glial cell heterogeneity influence on axon growth using a new coculture method

In the central nervous system of all mammals, severed axons after injury are unable to regenerate to their original targets and functional recovery is very poor. The failure of axon regeneration is a combined result of several factors including the hostile glial cell environment, inhibitory myelin related molecules and decreased intrinsic neuron regenerative capacity. Astrocytes are the most predominant glial cell type in central nervous system and play important role in axon functions under physiology and pathology conditions. Contrast to the homologous oligodendrocytes, astrocytes are a heterogeneous cell population composed by different astrocyte subpopulations with diverse morphologies and gene expression. The functional significance of this heterogeneity, such as their influences on axon growth, is largely unknown. To study the glial cell, especially the function of astrocyte heterogeneity in neuron behavior, we established a new method by co-culturing high purified dorsal root ganglia neurons with glial cells obtained from the rat cortex. By this technique, we were able to directly compare neuron adhesion and axon growth on different astrocytes subpopulations under the same condition. In this report, we give the detailed protocol of this method for astrocytes isolation and culture, dorsal root ganglia neurons isolation and purification, and the co-culture of DRG neurons with astrocytes. This method could also be extended to other brain regions to study cellular or regional specific interaction between neurons and glial cells.