Figure 1.

Isolation and differentiation of adult oligodendrocyte precursor cells (OPCs) in vitro. Adult OPCs were purified from the spinal cord of adult rats by immunopanning with the O4 antibody. The proliferating precursors displayed a characteristic adult OPC morphology with several small short processes emanating from a small round cell body (A). All cells expressed O4 (B), A2B5 (B), and NG2 (D, E). In the presence of fibroblast growth factor 2 (FGF2) and platelet-derived growth factor aa (PDGFaa), adult OPCs divided and are readily labeled by BrdU (B, C). These OPCs proliferated for multiple passages without changing phenotypes (F). Data in (F) were the mean ± SD of four independent experiments. Three days after withdrawal of FGF2 and PDGFaa, OPCs constitutively differentiated into OLs expressing O1 (G). Five days after differentiation, the majority of adult OPCs differentiated into mature OLs expressing CNPase (H) and MBP (I). When differentiated in the presence of 10% fetal bovine serum, more than 60% of the cells differentiated into GFAP+ astrocytes (J) that also expressed A2B5 and had a typical stellate morphology of type 2 astrocytes (J). Scale bars = 25 μm (A-C, G, J), 10 μm (D), 20 μm (E, I), and 50 μm (H). Abbreviations: BrdU, 5-bromo-2′-deoxyuridine; CNPase, 2′,3′-cyclic nucleotide phosphodiesterase; GFAP, glial fibrillary acidic protein; MBP, myelin basic protein.