Histological assessment of chondrogenesis in mesenchymal stem cell aggregates after adenoviral Indian hedgehog gene transfer. Following genetic modification with (a) Ad.GFP (negative control), (b) Ad.IHH (IHH), (c) Ad.IHH and Ad.TGF-β1 (IHH + TGF-β1), (d) Ad.IHH and Ad.BMP-2 (IHH + BMP-2), or (e) Ad.TGF-β1 or Ad.BMP-2 only (positive control; TGF-β1 or BMP-2) at 5 × 102 virus particles/cells, mesenchymal stem cells were maintained as pellets for 3 weeks until aggregates were harvested and processed. Representative sections after 10 and 21 days are shown. Left: H & E staining for evaluation of cellularity and cell morphology. Right: Metachromatic staining with Alcian Blue for detection of matrix proteoglycans. Panels 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.
Steinert et al. Arthritis Research & Therapy 2012 14:R168 doi:10.1186/ar3921