Figure 4

Effects of pentosan polysulfate on proteoglycan deposition by mesenchymal precursor cells in micromass cultures. Photomicrographs of mesenchymal precursor stem cell micromass cultures maintained in the absence and presence of pentosan polysulfate (PPS) for 10 days then stained with Alcian blue as described in the text: (a) 0.0 μg/ml PPS, (b) 1.0 μg/ml PPS, (c) 2.5 μg/ml PPS, (d) 5.0 μg/ml PPS, (e) 10.0 μg/ml PPS, and (f) 20 μg/ml PPS. Note the more intense staining with the dye at concentrations ≥ 2.5 μg/ml PPS, indicating the presence of higher levels of proteoglycans in these cultures.