Chitosan/Sodium Tripolyphosphate/Sodium Alginate/miRNA-34c-5p Antagomir Scaffolds Promote the Functionality of Rabbit Cranial Parietal Repair

Purpose: MicroRNA-34c-5p (miR-34c-5p) plays a pivotal role in bone remodeling, yet its therapeutic potential is hindered by challenges such as instability, limited cellular internalization, and immune responses. This study was aimed at developing innovative scaffolds capable of efficiently delivering microRNAs (miRNAs), specifically miR-34c-5p. Methods: Chitosan (CS)/sodium tripolyphosphate (STPP)/sodium alginate (SA) scaffolds, referred to as CTS scaffolds, were synthesized at a specific ratio and characterized using dynamic light scattering and scanning electron microscopy (SEM). Cytotoxicity assessments were conducted through cell activity staining. The loading capacity and releasing performance of miRNAs were quantified using spectrophotometry. Subsequently, the in vivo efficacy of miR-34c-5p Agomir/Antagomir in regulating bone repair was evaluated in the rabbit cranial bone defect model, with micro-CT scanning and histological analysis conducted at 4, 8, and 12 weeks. Results: CTS scaffolds with a composition ratio of 1:0.2:0.1 were successfully synthesized, exhibiting a mean particle size of 360.1 nm. SEM revealed scaffolds had the porous spongy structure. Cell activity staining confirmed the excellent biocompatibility of the CTS scaffolds. Spectrophotometry demonstrated miR-34c-5p Antagomir were continually released, reaching 91.41% within 30 days. Differential new bone formation was observed between the miR-34c-5p Agomir and Antagomir groups. Micro-CT imaging and histological staining revealed varying degrees of bone regeneration, with notable improvements in the miR-34c-5p Antagomir group. Conclusion: CTS scaffolds with a composition ratio of 1:0.2:0.1 demonstrate favorable biocompatibility and enable efficient loading and sustained release of miR-34c-5p Antagomir. The study suggests potential applications of miR-34c-5p Antagomir in promoting bone repair and highlights the promise of innovative scaffolds for therapeutic miRNAs administration in bone regeneration. Keywords: microRNA, scaffold, bone remodeling, chitosan