Adipose-derived mesenchymal stem cells combined with platinum nanoparticles accelerate fracture healing in a rat tibial fracture model

BACKGROUND: At present, bone union delay or failure remains challenging for clinicians. It has been reported that adipose-derived mesenchymal stem cells (ADMSCs) offer a promising way to promote bone fracture healing. In recent years, nanomaterials have been applied in regenerative medicine. This study aimed to investigate whether ADMSCs combined with platinum nanoparticles (PtNPs) could further improve fracture healing on the basis of ADMSCs. METHODS: ADMSCs were co-cultured with PtNPs in vitro to investigate the effect of PtNPs on the differentiation of ADMSCs. Twenty Sprague-Dawley (SD) rats were randomly divided into four groups (with five rats in each group). The left tibias of all rats were fractured. Phosphate-buffered saline (PBS), PtNPs, ADMSC, and ADMSC mixed with PtNPs were then injected into the fracture sites based on the group classifications. The fracture was monitored by X-ray immediately after the fracture and on days 14 and 28 post-fracture. The tibias of the rats were subsequently harvested after the last X-ray and evaluated by micro computed tomography (micro-CT), histological analysis, and immunohistochemical detection. RESULTS: PtNPs significantly enhanced the osteogenic differentiation of ADMSCs in vitro. On days 14 and 28 post-fracture, the radiographic score of the ADMSC + PtNPs group was higher than that of the ADMSC group, the score of the ADMSC group was higher than that of the PtNPs and control groups, and there was no significant difference between the PtNPs and control groups. Micro-CT confirmed that combined ADMSCs with PtNPs were more effective than using ADMSCs alone in promoting fracture healing. The histological and immunohistochemical results further supported this conclusion. CONCLUSIONS: Our findings demonstrated that PtNPs could promote osteogenic differentiation of ADMSC in vitro. ADMSCs combined with PtNPs could accelerate fracture healing further in vivo and are a promising a potential method for the treatment of fracture healing.