Background: Delay or failure of bone union is a significant clinical challenge all over the world, and it has been reported that bone marrow mesenchymal stem cells (BMSCs) offer a promising approach to accelerate bone fracture healing. Se can modulate the proliferation and differentiation of BMSCs. Se-treatment enhances the osteoblastic differentiation of BMSCs and inhibiting the differentiation and formation of mature osteoclasts. The purpose of this study was to assess the effects of porous Se@SiO₂ nanocomposite on bone regeneration and the underlying biological mechanisms.
Methods: We oxidized Se^2- to develop Se quantum dots, then we used the Se quantum dots to form a solid Se@SiO₂ nanocomposite which was then coated with polyvinylpyrrolidone (PVP) and etched in hot water to synthesize porous Se@SiO₂ nanocomposite. We used XRD pattern to assess the phase structure of the solid Se@SiO₂ nanocomposite. The morphology of porous Se@SiO₂ nanocomposite were evaluated by scanning electron microscope (SEM) and the biocompatibility of porous Se@SiO₂ nanocomposite were investigated by cell counting kit-8 (CCK-8) assays. Then, a release assay was also performed. We used a Transwell assay to determine cell mobility in response to the porous Se@SiO₂ nanocomposite. For in vitro experiments, BMSCs were divided into four groups to detect reactive oxygen species (ROS) generation, cell apoptosis, alkaline phosphatase activity, calcium deposition, gene activation and protein expression. For in vivo experiments, femur fracture model of rats was constructed to assess the osteogenic effects of porous Se@SiO₂ nanocomposite.
Results: In vitro, intervention with porous Se@SiO₂ nanocomposite can promote migration and osteogenic differentiation of BMSCs, and protect BMSCs against H₂O₂-induced inhibition of osteogenic differentiation. In vivo, we demonstrated that the porous Se@SiO₂ nanocomposite accelerated bone fracture healing using a rat femur fracture model.
Conclusion: Porous Se@SiO₂ nanocomposite promotes migration and osteogenesis differentiation of rat BMSCs and accelerates bone fracture healing, and porous Se@SiO₂ nanocomposite may provide clinic benefit for bone tissue engineering.
Keywords: bone marrow mesenchymal stem cells, porous Se@SiO₂ nanocomposite, antioxidant, migration, osteogenic differentiation