Figure 4.

Immunohistochemical analyses for cartilage matrix proteins of mesenchymal stem cell aggregate culture after chondrogenic induction. Cells were infected with (b) Ad.IHH, (c) Ad.IHH + Ad.TGF-β1, (d) Ad.IHH + Ad.BMP-2, or (a) Ad.GFP (control) at 5 × 10² virus particles/cells, and immunohistochemical stainings were performed on culture days 10 and 21 or representative sections for collagen type II (left panels) and chondroitin-4-sulfate (right panels). Regions of positive immunostaining appear red. Panels are reproduced at low (50×; bar = 200 μm) and high (200×; bar = 50 μm) magnification as indicated. Ad., adenoviral vector; BMP, bone morphogenetic protein; IHH, Indian hedgehog; TGF-β, transforming growth factor beta.