Figure 4

Co-culture of hBMSCs and hACCs improved cartilage formation in an ex vivo cartilage defect model. Cell pellets (ACCs, BMSCs, and ACCs+BMSCs) were seeded into an ex vivo cartilage defect after 3 weeks of chondrogenic induction and sealed in matrigel before being implanted subcutaneously in SCID mice for a further 3 weeks. (a) After 3 weeks both the ACCs-only pellets and mixed cell pellets can be seen underneath a smooth, white surface, showing no signs of blood vessels invasion. By contrast, with the BMSCs-only pellets and empty controls there was clear evidence of blood vessel formation. Representative images are shown from experiments from three pellets per group, sourced from three different patients; scale bar=50 μm. (b) Safranin-O staining was used to assess ECM proteoglycan deposition following 3 weeks subcutatneous implantation in SCID mice. There was significantly more intense staining in the mixed ACCs+BMSCs group, followed by the ACCs group compared with the BMSCs and empty control group. (c) Bern scores of cartilage formation in ACCs (n=3), BMSCs (n=3), and ACCs+BMSCs groups (n=3). Results are representative of studies performed on three different patient samples with three technical replicates. Data are reported as means±s.d.; *P<0.05.