Long-term culture of canine bone marrow cells

Conditions that allow the growth of canine marrow cells in long-term marrow culture are described. The quality of the culture conditions was evaluated based on the weekly number of granulocyte-macrophage colony-forming units (CFU-GM) in the nonadherent cell fraction. Using this parameter, the highest number of CFU-GM was obtained when marrow cells were incubated at 37 degrees C in RPMI-1640 or McCoy's 5A medium supplemented with 20% prescreened horse serum without addition of hydrocortisone. CFU-GM colonies could be regularly grown out of the nonadherent cell fraction for 20-31 weeks, after recharging the cultures with 1.5 X 10(7) mononuclear autologous marrow cells 1 week after establishing the stromal cell layer.