Temporal expression of myelin-specific components in neonatal mouse brain cultures: evidence that 2',3'-cyclic nucleotide 3'-phosphodiesterase appears prior to galactocerebroside

A range of antibodies to cell-specific markers was employed to characterize and quantify the cell types present in neonatal mouse brain cell cultures. Astrocytes were the major cell type to develop in culture and formed a bed layer by 5-7 days in vitro (DIV). A population of cells appeared on this layer which consisted of oligodendrocytes, progenitor cells and microglia. Some neurons were detected in the cultures up to at least 27 DIV. With time, the number of progenitor cells decreased in the cultures and there was a concomitant increase in the number of oligodendrocytes. Maximal numbers of cells expressing galactocerebroside (GC), 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP) and myelin-associated glycoprotein were observed at 18 DIV. The highest number of cells expressing myelin basic protein and proteolipid protein were observed at 25-30 and 35-40 DIV, respectively. Double-label studies with antibodies to A2B5/CNP and A2B5/GC showed that several A2B5+,CNP+ cells were present at 6 DIV. In contrast, no A2B5+,GC+ cells could be seen at this age. Confirming these findings, some CNP+,GC- cells were observed when cells were double-labeled with antibodies to CNP and GC. These findings suggested that the expression of CNP precedes that of GC in oligodendrocytes in these cultures.