Fig. 1
Characterization of AC- and MSC-derived engineered cartilage. Biphasic osteochondral units were seeded with 5 × 105 human articular chondrocytes (AC) or mesenchymal stromal cells (MSC) and cultured for 3, 21 or 35 days under chondrogenic conditions. A Standard paraffin sections were stained with Safranin O/Fast Green to visualize GAG deposition (scale bar: 50 μm, overview pictures are presented as insets (scale bar: 1 mm); representative pictures are shown; n = 4-8 donors per group). B Mean GAG content ± SD of AC- and MSC-seeded neocartilage measured by DMMB assay, referred to the DNA content (n = 3–10 constructs per time point and group). Two-tailed t-test, *p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001 in comparison to day 3. C Construct hardness over culture time was assessed in VLRH units (n = 3–8 constructs per time point and group). Hardness of native cartilage plugs is indicated as a dotted line. D Pearson correlation of VLRH and GAG/DNA (n = 27 samples)