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. Author manuscript; available in PMC: 2013 Nov 26.
Published in final edited form as: Cell Transplant. 2012 Apr 2;21(10):10.3727/096368912X636821. doi: 10.3727/096368912X636821

Figure 3.

Figure 3

Osteogenesis is diminished in MSCs harvested from aged compared to young dogs. First passage cultures of MSCs obtained from bone marrow of young and aged donors were cultured in control and osteogenic media. The effect of age on MSC response to osteoinduction was assessed by: quantitating alkaline phosphatase (AP) activity, osteogenic marker induction and mineralization. (A) Following 6 days of osteogenic induction, AP activity was determined and normalized on the basis of cell number. Each box represents the interquartile range (25th to 75th percentiles). The horizontal line within each box represents the median. Comparison of AP activity normalized to cell number revealed a significant decrease of AP in aged dog samples cultured under osteogenic conditions relative to those obtained from young dogs (*p < 0.05). (B) MSCs harvested from the femoral BM cavity of young and aged donors cultured in osteogenic conditions showed mRNA induction of both bone sialoprotein (BSP) and osteocalcin (OCN) compared to control cultures (14 and 21 days after induction, respectively), although cultures of MSCs from aged donors had a diminished response to osteo inducers relative to those harvested from young donors. Fold induction of OCN expression is significantly diminished in MSCs harvested from aged dogs relative to young dogs (*p < 0.05). (C) Analysis of quantified Alizarin red S extracted from the matrix of femoral bone marrow MSC cultures from young and aged donors cultured under either control or osteogenic conditions for 14 days reveals a significant effect of age on matrix mineralization. MSCs from both young and aged dogs respond to osteoinducers but those from aged donors are significantly less responsive than those from young donors (*p < 0.05). (D) Alizarin red S staining of mineralized matrix in representative cultures from a young and an aged donor showing increasing deposition of a richly mineralized matrix in the young donor cells as compared to aged donor cells at 7, 14, and 21 days. Mineralization also increases over time in aged dog MSC cultures, albeit at a diminished amount relative to young dogs at corresponding time points.