Fig. 4

Histochemical analyses for hypertrophy of MSC pellet cultures after chondrogenic induction with adenoviral gene transfer of SOX9 compared to TGFB1 or IGF1 alone, or in combination. MSC pellet cultures genetically modified 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 (f) were maintained in serum-free medium for 21 days. Representative sections after 10 and 21 days are shown, which were stained histochemically for alkaline phosphatase (ALP). Uninfected, with recombinant TGF-β1 treated pellets after 21 days of culture are shown for comparison (g). (a-g) Panels are reproduced at low (50x; bar = 200 μm) or high (200x; bar = 50 or 100 μm) magnification as indicated, and regions of positive staining for ALP appear blue