Immunocytochemical double labeling of glial fibrillary acidic protein and transferrin permits the identification of astrocytes and oligodendrocytes in the rat brain.

Sequential immunocytochemical double labeling of glial fibrillary acidic protein (GFAP) and transferrin (Tf) was used for the simultaneous identification of astrocytes and oligodendrocytes in paraffin-embedded sections of the rat brain. Paraformaldehyde or formalin-alcohol-acetic acid fixation followed by protease treatment of paraffin-embedded sections provided the most satisfactory double-labeling. The results demonstrated GFAP-positive astrocytes and Tf-positive oligodendrocytes as two subpopulations of glia with no overlap. Our results suggest that, with some exceptions, immunocytochemical double labeling of GFAP and Tf has a potential application for the simultaneous identification of astrocytes and oligodendrocytes in the rat brain.