Immunocytochemical characterisation of cell cultures grown from dissociated 1-2-day post-natal rat cerebral tissue. A developmental study.

A range of cell-specific markers have been employed with immunocytochemical methods to characterise and quantitate the cell types present in mixed brain cell cultures derived from dissociated 1-2-day post-natal rat cerebral hemispheres and grown in the presence of FCS. Protoplasmic astrocytes (GFAP+, A2B5-) were the major cell type to develop in culture, a confluent monolayer forming in 5-8 days. A population of smaller round cells of oligodendrocyte-like morphology appeared on this astrocyte layer. Greater than 70% of these smaller cells were GC- and thus were not oligodendrocytes. The GC- cells were A2B5+ and, in early cultures, may therefore be progenitor glial cells. Examination of GFAP and A2B5 co-expression by these smaller cells was difficult due to the dense underlying GFAP+ astrocyte layer. In less dense areas of older cultures these smaller cells with processes were GFAP+ and A2B5+: these are Type 2, fibrous astrocytes. GC+ oligodendrocytes, comprising 5-10% of the total identified cell population, were initially distributed over the astrocyte monolayer; in older cultures (after about 8 days) GC+ cells were observed in clumps over places where NF+ cells were identifiable. Such GC+ cells mostly became MBP+. Neurones accounted for about 6% of the identifiable cells in early cultures but a lower percentage in older cultures. Minor populations of ependymal cells and macrophages were present; cells displaying fibronectin, fibroblasts, were rarely identified. Use of horse serum in place of FCS gave lower yields of GC+ cells in cultures, slowed down astrocyte development, and resulted in the formation of trunks of GFAP+ cells throughout cultures. Other sera gave lower numbers of GC+ cells.