The effect of combined application of TGFb-1, BMP-2, and COLLOSS E on the development of bone marrow derived osteoblast-like cells in vitro

This study investigated the combined application of Transforming Growth Factor b-1 (TGFb-1) and Bone Morphogenetic Protein-2 (BMP-2) to stimulate osteogenic expression in vitro. TGFb-1 and BMP-2 fulfill specific roles in the formation of new bone. COLLOSS E, a bone-derived collagen product containing a variety of naturally occurring growth factors, was also used. Growth factors were administered to osteoblast-like cells from rat bone marrow (RBM). Proliferation and differentiation were monitored up to 24 days, by measuring total DNA content, alkaline phosphatase activity, and calcium content. Genetic expression of a set of differentiation markers at day 7 was measured by Q-PCR. Adding BMP-2 alone induced high proliferation rates, compared to the growth factor supplemented groups, and it induced high differentiation rates, compared to the control group. Adding TGFb-1 combined with BMP-2, TGFb-1 alone, or COLLOSS E resulted in a significant decrease in proliferation rate, but an increase in differentiation rate, compared to the control group. Additive or synergistic effects of application of TGFb-1 and BMP-2 were not observed. The observed effects of COLLOSS E mainly resembled those of TGFb-1 application alone. It can be concluded that BMP-2 is the most suitable candidate for osteogenic stimulation of RBM cells in these settings. 2007 Wiley Periodicals, Inc. J Biomed Mater Res 86A: 788–795, 2008