Comparative characterization of mesenchymal bone marrow stromal cells at early and late stages of culturing
ABSTRACT The mesenchymal stromal cell is a multipotent precursor of osteoblasts, adipocytes, and some other cell types. In this study,
a comparative analysis of cultured mesenchymal stromal cells from the rat bone marrow at the early and late stages of subculturing
has been performed using molecular genetic and cytological methods. The culture has undergone 11 passages during 140 days.
Upon long-term culturing, the mesenchymal stromal cells have proved to lose their potential for adipogenic differentiation
but preserve the potential for osteogenesis. Morphological characters typical of osteogenic differentiation can be observed
at the earlier stages of culturing (passages 1–4) but disappear at later stages (passages 9–11), despite mineralization of
the extracellular matrix and the expression of osteogenic differentiation markers. A comparative analysis of the proliferation
potential of stromal cells has shown that differences in the period of cell population doubling at the early and later stages
of culturing are insignificant. An almost complete arrest of cell growth has been observed in the middle of the culture period
(passages 5 and 6).