Effect of culture substrates and fibroblast growth factor addition on the proliferation and differentiation of rat bone marrow stromal cells

This study is an investigation of the proliferation and differentiation of bone marrow stromal cells (BMSCs) on film substrates with different surface properties. Films of noncharged polymers with several water wettabilities; cell culture plates coated with collagen type I or IV, gelatin, or basic fibroblast growth factor (bFGF); and glass were used. BMSCs isolated from rat bone marrow were cultured on the various substrates in medium with dexamethasone [Dex(+)] or without dexamethasone [Dex(-)] to assess cell proliferation and differentiation. The number of proliferated BMSCs depended on the water wettability of substrates, although the cell number was greater in Dex(-) medium than in Dex(+) medium. Protein-coated substrates exhibited a high proliferation rate compared with noncoated substrates. Alkaline phosphatase (ALP) activity increased with increasing cell number, whereas ALP activity per cell correlated well with cell number. When cultured in Dex(+) medium containing bFGF or on culture plates coated with bFGF, BMSC proliferation tended toward enhancement with an increase in the amount of bFGF added in solution form, whereas it did not depend on the amount of bFGF in coated form. On the other hand, ALP activity and calcium content of BMSCs became maximal with bFGF coated at about 1 x 10(3) to 2 x 10(3) ng, in contrast to bFGF in solution form. Irrespective of the amount of bFGF, ALP activity and calcium content levels for bFGF in coated form were higher than for bFGF in solution form. It is concluded that the type of culture substrate and the manner of addition of bFGF affect the proliferation and differentiation of BMSCs.