Fig. 1.
hMSCs display growth factor dependent differentiation behaviors at 2 weeks that are not apparent at 24 h. hMSCs were cultured on fibronectin-coated glass substrates at 3,000 cells per cm2 for 2 weeks in either (A) AD media, (B) BA or, (C) OS induction media. Differentiation behaviors for OS and AD phenotype were assessed by Fast Blue Staining (Blue stain) for positive alkaline phosphatase activity or Oil Red O staining (Red stain) for intracellular lipid accumulation respectively (FBOR). Inlays represent corresponding images of fluorescently labeled nuclei. (D) Quantitative analysis of FBOR staining demonstrates 75% fast blue positive cells in OS media and significantly (p < 0.05) less fast blue positive cells and almost no oil red O positive cells in AD and BA media. Error bars represent the standard deviation of N = 2 independent experiments. hMSCs were cultured for 18 h in (E) AD media (F) BA media, and (G) OS media. Cells were fixed and then stained for actin at 24 h of total culture time. (H) Traditional cell shape parameters (cell area and aspect ratio) demonstrated no significant differences between AD, BA, and OS-treated hMSCs at 24 h. Error bars represent the standard deviation for N = 350–437 cells.