Joint construction of micro-vibration stimulation and BCP scaffold for the enhanced bioactivity and self-adaptability tissue engineered bone graft
The bone defects caused by trauma and disease have become a major difficulty in the treatment of clinical bone defect, and bone tissue engineering became a promising treatment strategy. It was found that mechanical stimulation regulates the development of bone constructs by affecting the distribution and differentiation of cells on them. In this study, tissue-engineered bone grafts with enhanced bioactivity and self-adaptability were constructed by BMSCs and biphasic calcium phosphate (BCP) scaffolds under periodic micro-vibration stimulation (MVS) with frequency at 40 Hz, magnitude at 0.3 g. The results of the material characterization indicated that the BCP scaffolds created a more favourable osteogenic microenvironment with promoted calcium ion release, protein adsorption and mineralization deposition under micro-vibration stimulation. In vitro results showed that apoptosis of BMSCs increased significantly on day 1, but from days 3 on, the proliferation increased and apoptosis decreased. Cells were evenly distributed on the scaffolds, exhibiting tight adhesion in a flat-shape and distinct matrix mineralization. F-actin and ALP expression significantly increased and meanwhile osteogenesis-related genes including Runx2, Col-I, ALP, and OCN were significantly up-regulated. WesternBlotting results suggested that the ERK1/2 and Wnt/β-catenin signalling pathways were involved in the osteogenic behaviour of BMSCs induced by MVS. In vivo experiments showed that grafts had stronger osteoinduction and mechanical adaptability. Taking together, this study suggests that micro-vibration stimulation joint with BCP scaffolds with good osteoinduction could be a promising approach for constructing tissue engineered bone graft with enhanced bioactivity, mechanical adaptability, and bone regeneration repair capability.