Repair of mandibular defects by bone marrow stromal cells expressing the basic fibroblast growth factor transgene combined with multi-pore mineralized Bio-Oss.

The aim of the present study was to evaluate the effect of combining Bio‑Oss with bone marrow stromal cells (BMSCs) transfected with the basic fibroblast growth factor (bFGF) gene on bone regeneration during mandibular distraction of rabbits. BMSCs obtained from rabbits were transfected with bFGF gene‑encoding plasmids and proliferation rate and the differentiation marker alkaline phosphatase activity were measured. Following seeding into Bio‑Oss collagen and 9‑day culture in vitro, the surface morphology of the Bio‑Oss was assessed using scanning electron microscopy analysis. Three mandibular defects were induced in the lower border of the bilateral mandibular ramus in each New Zealand white rabbit (total n=6). Three scaffolds, group A (seeded with BMSCs/bFGF), B (seeded with BMSCs/pVAX1) and C (cell‑free), which had been cultured in vitro under standard cell culture conditions for 18 days, were implanted into mandibular defects under sterile conditions. Animals were sacrificed by anesthesia overdose 12 weeks following surgery and the scaffolds were extracted for bone mineral density and histological analyses. Results indicate that bFGF was successfully transfected into BMSCs. Proliferation and osteoblast differentiation of BMSCs were stimulated by bFGF in vitro. No differences were identified in surface morphology for Bio‑Oss loaded with variable groups of cells. At week 12 following implantation of Bio‑Oss scaffolds, mineralization of BMSCs in Bio‑Oss scaffolds was observed to be increased by bFGF. New bone and cartilage formation was revealed in hematoxylin and eosin‑stained sections in Bio‑Oss scaffolds and was most abundant in group A (BMSCs transfected with bFGF). In the current study, the bFGF gene was transfected into BMSCs and expressed successfully. bFGF promoted proliferation and differentiation of BMSCs in vitro and implantation of bFGF‑expressing BMSCs combined with Bio‑Oss enhanced new bone regeneration more effectively than traditional methods.