Cultures of Astroglia and Microglia from Primary Cultures of Mouse Neopallium

Brains of newborn rats or mice are generally used as the source of tissue for glial cultures. Only about 1% of cells survive the cell disaggregation process and culture environment, and neurons that survive die within the first few days of culturing. Such cultures contain progenitor cells and glia cells in different stages of differentiation (Alliot et al.,1991 ; Fedoroff et al., 1997 ; see also Chapter 14 ). Terminally differentiated glia cells, which can no longer divide, are overgrown by the proliferating, immature cells. How the cultures will develop, and which cell types (astroglia, oligodendroglia, ependymal cells, or microglia) will predominate, depend on the culture medium and the physical conditions under which the cells are grown (see also Chapters 12 and 14 ). The medium can be modified either by changing its chemically defined components or by adding or deleting serum. It is also possible to add growth factors and/or cytokines, either to the culture medium in pure recombinant form, or as medium conditioned by cells that produce and secrete growth factors/cytokines into the medium (the latter is considerably cheaper). The addition of cytokines to cultures can have a dramatic effect on the morphology and function of cells. It should be noted that cytokines and growth factors may affect more than one cell type, and may initiate variable effects in different cell types. The growth factors/cytokines may interact with other factors in the medium synergistically, additively, or in an inhibitory way. It is important to remember that the half-life of cytokines is short. However, the cytokines/growth factors can be added to ,the culture in microcapsules, which release the factors at a constant rate over a long period of time, thus assuring a constant concentration of a given factor to culture medium over long periods of time (Maysinger et al., 1992 ; Maysinger et al., 1996a , Maysinger et al., 1996b ).