We studied the effect of significantly reduced oxygen content (0% O(2)in gaseous phase) in culture medium on rat bone marrow mesenchymal stromal precursor cells. The cells retained their morphology and expression of characteristic markers during several days under these conditions; they were viable, proliferated, and some cultured cells were even capable of realizing the initial stages of osteogenic and adipogenic differentiation. Further culturing of precursor cells under conditions of anoxia led to activation of apoptosis in cultures and to progressive necrosis.