Figure 1: The effect of the gelatin concentration of gelatin-coated two-dimensional (2D) matrix culture dishes on the number and colony size of colony forming unit-fibroblasts (CFU-Fs) derived from mesenchymal stem cells obtained from rat bone marrow primary cell populations. Bone-marrow-derived primary cells were seeded onto culture plates coated with 0, 0.1, 0.5, 1 and 2% (wt/v) gelatin and cultured for 7 days. The CFU-Fs were analyzed using the Image and Microscope Technology (IMT) solution software under an inverted microscope. (a) The CFU-Fs had a typical fibroblastic morphology and were stained by crystal violet. (b) A significant increase in the number of CFU-Fs was detected in bone-marrow-derived mesenchymal stem cells (BM-MSCs) cultured on 0.5, 1 and 2% (wt/v) gelatin matrices. (c) The CFU-Fs with the largest diameters were those of BM-MSCs cultured on 1% (wt/v) gelatin matrix. All data shown are means ± S.D. of four independent experiments. Scale bar (large), 400 μm. Scale bar (small), 1 cm. *,** .