Abstract
Introduction
Bioactive glasses (BGs) promote osteogenic differentiation of bone progenitor cells by releasing therapeutically active ions. The well-described 45S5-BG (in mol%: SiO2 46.13; P2O5 2.60; CaO 26.91; Na2O 24.35) was supplemented with CaF2 and NaF being added to the batch at nominal 5 (F5-BG) and 25 mol% (F25-BG), respectively. While the effect on physical and chemical properties has already been characterized, the biological properties require further studies. This study investigates the effects of fluoride-supplemented BGs on the osteogenic and angiogenic properties of human bone marrow mesenchymal stromal cells (BMSCs) in vitro.
Method
BMSCs were co-cultured with melt-derived 45S5-BG, F5-BG, or F25-BG in ascending concentrations (1, 2 and 3 mg/ml). At 7 days, cell number was determined by 4,6-diamidine-2-phenylindole (DAPI) staining and cell viability by fluorescein diacetate (FDA) assay. The osteogenic potential of the BGs was evaluated through alkaline phosphatase (ALP) gene expression and activity, along with bone morphogenetic protein-2 (BMP2) gene expression and protein concentration. Vascular endothelial growth factor (VEGF) gene expression and protein concentration assessed angiogenic potential. As control, BMSCs were cultured without BG exposure.
Result
All BGs significantly promoted cell number and viability, with F25-BG showing the highest count at 3 mg/ml. Osteogenic markers showed a significant decrease in ALP gene expression and activity, especially at higher concentrations. All BG groups demonstrated increased BMP2 protein concentration and gene expression compared to the control, with higher BG and fluoride concentrations correlating with greater increases in BMP2. VEGF gene expression increased in all analysed BGs. The fluoride-free BG group had the highest VEGF protein concentrations, while the F25 BG group showed the highest VEGF gene expression.
Conclusion
The fluoride-substituted BGs exhibit excellent cytocompatibility, enhance BMSC proliferation and positively affect BMP2 gene expression and levels, suggesting their potential for osteogenic differentiation. Further research is necessary to assess their proangiogenic effect and potential advantages over 45S5-BG.
