Electrospun sandwich mesh structures loaded with naringenin and vitamin K2 polycaprolactone/gelatin nanofibers synergistically promote bone regeneration

Osteoblasts and osteoclasts play a crucial role in the dynamically coupled balance during bone regeneration and remodeling. They complement and restrict each other in the human body. Decreased osteoblasts lead to insufficient bone formation or excessive formation of osteoclasts, leading to increased bone resorption, which will destroy the structure of the bone tissue. This will greatly increase the risk of diseases such as osteoporosis and nonunions caused by bone defects. Herein, gelatin and polycaprolactone were used as substrates, and biomaterial membranes with mesh and sandwich structures were constructed using the electrospinning technology. Naringenin was loaded into the shell, and vitamin K2 was loaded into the core layer of the nanofibrous membrane. The biocompatibility and osteogenic capacity of the membranes were assessed in vitro using mouse bone marrow mesenchymal stem cells (BMSCs). During osteoclast induction, the receptor activator of nuclear factor kappa-Β ligand (RANKL) was used to coculture RAW264.7 cells with various materials. The regulatory effect of various membranes on osteoclast growth was evaluated by detecting the expression levels of osteoclast-related genes and proteins in the cells. Subsequently, we constructed a model of a rat skull defect and implanted different membranes into the defect. Then, we evaluated the new bone formation in the defect using histological staining and micro-computed tomography after 4 and 8 weeks. The results of in vitro experiments confirmed that the incorporation of naringenin and vitamin K2 stimulated the expression of osteogenesis-related genes and the secretion of osteogenesis-related proteins. Simultaneously, the results showed that naringenin and vitamin K2 inhibited the formation and growth of osteoclasts. Therefore, naringenin and vitamin K2 have a synergistic effect in promoting bone growth and regulating osteoclast growth.