Chitosan composite scaffold combined with bone marrow-derived mesenchymal stem cells for bone regeneration: in vitro and in vivo evaluation

The study aimed to develop a chitosan (CS)-based scaffold for repairing calvarial bone defects. We fabricated composite scaffolds made of CS and bovine-derived xenograft (BDX), characterized their physicochemical properties including pore size and porosity, absorption, degradation, and compressive strength, compared their efficacy to support in vitro proliferation and differentiation of human jaw bone marrow-derived mesenchymal stem cells (hJBMMSCs), and evaluated their bone regeneration capacity in critical-size rat calvarial defects. The CS/BDX (mass ratio of 40:60) composite scaffold with porosity of 46.23% and pore size of 98.23 μm exhibited significantly enhanced compressive strength than the CS scaffold (59.33 ± 4.29 vs. 18.82 ± 2.49 Kpa). The CS/BDX (40:60) scaffold induced better cell attachment and promoted more osteogenic differentiation of hJBMMSCs than the CS scaffold. The CS/BDX (40:60) scaffold seeded with hJBMMSCs was the most effective in supporting new bone formation, as evidenced by better histomorphometry results, larger new bone area, and more obvious mature lamellar bone formation compared to other groups in rat calvarial defects 8 weeks after implantation. These results suggest that CS/BDX composite scaffold combining with hJBMMSCs has the potential for bone defect regeneration.