Porous Se@SiO(2) nanocomposite promotes migration and osteogenic differentiation of rat bone marrow mesenchymal stem cell to accelerate bone fracture healing in a rat model

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@SiO(2) 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@SiO(2) nanocomposite which was then coated with polyvinylpyrrolidone (PVP) and etched in hot water to synthesize porous Se@SiO(2) nanocomposite. We used XRD pattern to assess the phase structure of the solid Se@SiO(2) nanocomposite. The morphology of porous Se@SiO(2) nanocomposite were evaluated by scanning electron microscope (SEM) and the biocompatibility of porous Se@SiO(2) 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@SiO(2) 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@SiO(2) nanocomposite. Results: In vitro, intervention with porous Se@SiO(2) nanocomposite can promote migration and osteogenic differentiation of BMSCs, and protect BMSCs against H(2)O(2)-induced inhibition of osteogenic differentiation. In vivo, we demonstrated that the porous Se@SiO(2) nanocomposite accelerated bone fracture healing using a rat femur fracture model. Conclusion: Porous Se@SiO(2) nanocomposite promotes migration and osteogenesis differentiation of rat BMSCs and accelerates bone fracture healing, and porous Se@SiO(2) nanocomposite may provide clinic benefit for bone tissue engineering.