Osteogenesis of large segmental radius defects enhanced by basic fibroblast growth factor activated bone marrow stromal cells grown on non-woven hyaluronic acid-based polymer scaffold

Osteogenesis of large segmental radius defects in a rat model was studied by implanting a biodegradable non-woven hyaluronic acid-based polymer scaffold (Hyaff ®11) alone or in combination with bone marrow stromal cells (BMSCs). These cells had been previously grown in vitro in mineralising medium either supplemented with basic fibroblast growth factor (bFGF) or unsupplemented. The healing of bone defects was evaluated at 40, 80, 160 and 200 days and the repair process investigated by radiographic, histomorphometric (assessment of new bone growth and lamellar bone) and histological analyses (toluidine blue and von Kossa staining). Mineralisation of bone defects occurred in the presence of the Hyaff ® 11 scaffold alone or when combined with BMSCs grown with or without bFGF, but each process had a different timing. In particular, bFGF significantly induced mineralisation from day 40, whereas 160 days were necessary for direct evidence that a similar process was developing under the other two conditions tested (scaffold alone or with BMSCs). Radiographic score, new bone growth and lamellar bone percentage were highly correlated. The present outcomes were further confirmed by toluidine blue and von Kossa staining. According to these in vivo findings, the Hyaff ® 11 scaffold is an appropriate carrier vehicle for the repair of bone defects; additionally, it can significantly accelerate bone mineralisation in combination with BMSCs and bFGF.