RESTRICTED GROWTH-POTENTIAL OF RAT NEURAL PRECURSORS AS COMPARED TO MOUSE

Epidermal growth factor (EGF) responsive precursors isolated from the developing mouse striatum could be continually expanded in culture as free-floating spheres of cells for over 50 days. Under identical condi tions, EGF-responsive precursors from the developing rat striatum coul d only be expanded for between 21 and 28 days, after which crisis ensu ed and there was a reduction in cell number at each passage. The outer regions of 28-day-old rat spheres contained a heterogeneous populatio n of both dividing and dying cells while the cores were full of dying cells, many of which showed features consistent with apoptosis. Fibrob last growth factor-2 (FGF-2) alone did not lead to an expansion in rat striatal precursor cell number under the conditions used here. EGF co mbined with FGF-2 acted synergistically on cell growth, but did not pr event the final senescence and death of the rat precursors. (C) 1997 E lsevier Science B.V.