Growth and gliotic response of astrocytes in vitro

We investigated the development of astrocytes in mechanically dissociated primary cultures of foetal and neonatal rat brain grown in different culture media using immunofluorescence and antiserum to glial fibrillary acidic protein (GFAP). GFAP-positive cells developed at a time corresponding to the 16th day of embryonic development and initially grew more slowly in Dulbecco's modified Eagle's Medium (DMEM) than in Medium 199 (M199) or Modified Eagle's Medium (MEM), but as the cultures matured a greater proportion of GFAP-positive cells was obtained in DMEM, resulting in relatively pure populations of GFAP-positive cells after 1-2 months in vitro. GFAP-positive cells comprised process-bearing and fibroblastoid cell types and cells with intermediate morphology. Cultures in DMEM were also characterized by the appearance after 8-18 days in vitro of thick long bands of glial processes surrounding cyst-like spaces. The morphological change may represent a gliotic reaction to necrosis in vitro.