Collagen hydrogel incorporated with ginsenoside Rg1-loaded chitosan nanoparticles and adipose-derived stem cells enhances nasal bone fracture healing in rats

Facial bone fractures are extremely common with nasal bone fractures being among the most frequently fractured bones in the body. However, therapeutic approaches for nasal bone fracture treatment have focused primarily on mechanical reduction and stabilization of the fracture site without biologically stimulating tissue repair. The goal of this study was to engineer a nanocomposite collagen hydrogel therapeutic system loaded with ginsenoside Rg1-loaded chitosan nanoparticles (G.Rg1-CNPs) and adipose-derived stem cells (ASCs) to enhance nasal bone fracture healing. To accomplish this objective, G. Rg1-CNPs were synthesized by ionotropic gelation and characterized for encapsulation efficiency, drug loading capacity, release kinetics, and particle morphology. These nanoparticles were combined with collagen hydrogels with and without ASCs to create the hydrogel system. In vitro characterization evaluated included scanning electron microscopy (SEM), cell viability assay, degradation profile, and radical scavenging assay. In vivo evaluations were conducted using rat nasal bone fracture model and included histology, histomorphometry, and ELISA-based biomarker analysis. Following optimization, nanoparticles exhibited moderate encapsulation efficiency and loading capacity with burst release kinetics initially transitioning to sustained release profiles until 72 h. SEM imaging was used to confirm nanoparticle morphology and demonstrated porous interconnected microstructures formed when collagen gels were allowed to polymerize. Metabolic activity assays revealed ASCs incorporated into hydrogels maintained cellular viability and metabolism up to 7 days in vitro. Degradation studies indicated all hydrogel groups experienced steady degradation throughout the 12-day period. Antioxidant capacity studies showed G.Rg1-CNPs had significantly higher activity compared to blank nanoparticles. Animal studies demonstrated hydrogels containing ASCs and G.Rg1-CNPs had the highest overall healing response with improved tissue organization, collagen deposition, new bone formation, decreased expression of pro-inflammatory cytokines, increased anti-inflammatory cytokines, and angiogenic/osteogenic growth factor biomarkers when compared to all other treatment groups. Overall, this nanocomposite hydrogel system enhanced nasal bone fracture healing by creating an optimal regenerative microenvironment.