Fig. 2
Histological appearance of MSC pellets after chondrogenic induction by adenoviral gene transfer of SOX9 compared to TGFB1 or IGF1 alone or in combination. MSC monolayer cultures were infected with Ad.GFP (Control; a), Ad.SOX9 (b), Ad.TGFB1 + Ad.SOX9 (c), Ad.TGFB1 alone (d), Ad.IGF1 + Ad.SOX9 (e), or Ad.IGF1 alone (f) at 5 × 102 vp/cell, seeded into aggregates 24 h after infection and cultured in serum-free medium for 21 days. Representative sections after 10 and 21 days are shown, which were stained with H & E for evaluation of cellularity and cell morphology (left panels), and with alcian blue (right panels) for detection of matrix proteoglycan. Uninfected, with recombinant TGF-β1 treated pellets after 21 days of culture are shown for comparison (g). Panels (a-g) are reproduced at low (50x; bar = 200 μm) or high (200x; bar = 50 or 100 μm) magnification as indicated