FIG. 4.

Osteogenic, adipogenic, and chondrogenic differentiation of the transfected MSCs or control MSCs. (a) C57BL/6J MSCs were transfected with pMaxGFP (transfection) or not (control) at day 0 and, at day 3, incubated in appropriate differentiation media for osteogenesis, adipogenesis, and chondrogenesis as described in the Materials and Methods section. The mature osteoblasts with mineralization were stained with Alizarin Red S and show as red color; the lipidic vacuoles of adipocytes were stained with Oil-red-O and show as red color; the chondrocytes were stained with toluidine blue and show as dark blue. Original magnification, 100 × for osteoblasts and adipocytes; 200 × for chondrocytes. (b) C57BL/6J MSCs were infected with Lt.BMP2 at MOI = 100 (Lt.BMP2), or transfected with pMaxGFP (GFP), pCDH-CMV-mBMP2-EF1α-copGFP (BMP2), or not (control) at day 0. Cells were cultured in the normal growth medium and harvested at day 3 for measurement of ALP activity (U = μmol/min; n = 3) as described in the Materials and Methods section. The cells infected with Lt.BMP2 were used as a positive control. The data were analyzed by one-way ANOVA followed by the Dunnett's test for multiple comparisons. ***p < 0.001. ALP, alkaline phosphatase; BMP2, bone morphogenetic protein 2. Color images are available online.