Primary Cell Cultures for the Study of Myelination

Tissue culture allows the separate establishment of neurons and glia under a variety of conditions of substrate and media. By subsequent recombination of relatively pure cell populations, a number of questions of neuronal development and neuronal-glia interactions, specifically myelination, may be studied. In vivo, axons of dorsal root ganglion (DRG) neurons course through both the central nervous system (CNS) and peripheral nerve trunks, and induce myelination by both central (oligodendrocytes) and peripheral (Schwann cells) neuroglia. For this reason, and because dissociated DRG neurons are long-lived in vitro when nerve growth factor (NGF) is included in the medium, co-cultures of purified DRG neurons and purified myelinating cells (i.e., Schwann cells or oligodendrocytes) are ideal for the study of myelination. In culture, either peripheral nervous system (PNS) or CNS glial cells are added to the networks of nonneuronal cell-free disaggregated DRG neurons. When these co-cultures are provided with suitable medium, the glia expand in number; given another media, myelination occurs in several weeks.