Growth patterns of glial cells dissociated from newborn and aged mouse brain with cell passage.

Glial cell cultures derived from newborn and aged (18-month-old) mouse cerebral hemispheres and maintained up to cell passage 11 were characterized immunocytochemically by using glial fibrillary acidic protein (GFA), and biochemically by using glutamine synthetase (GS), for astrocytes, and 2',3' cyclic nucleotide 3' phosphohydrolase (CNP) for oligodendrocytes. We report here the changes occurring during passages 5-11. GS and CNP activities did not significantly change with cell passage in cultures from newborn mouse. In cultures derived from aged mouse, CNP activity did not change significantly whereas GS activity increased severalfold. A characteristic finding in higher cell passages (passage #7) was the loss of GFA-positive stained cells and the appearance of multinucleated cells. We interpret these changes in culture to represent possible signs of cellular senescence.