Investigating the anti-inflammatory and bone repair-promoting effects of an injectable porous hydrogel containing magnesium ions in a rat periodontitis mode

Periodontitis is associated with several systemic diseases, and advanced periodontitis is often linked to an extensive inflammatory microenvironment and irregularly shaped alveolar bone defects. However, eliminating periodontal inflammation in a minimally invasive manner while repairing irregularly shaped bone defects is clinically challenging. In comparison to traditional bone grafts, a thermo-sensitive hydrogel can be injected into deep periodontal pockets, forming and filling the alveolar bone defects in situ. In this study, porous injectable thermo-sensitive hydrogels containing magnesium ions were prepared by adding magnesium particles (MPs) to a glycerophosphate solution and combining this mixture with a chitosan solution. The incorporation of MPs created interconnected pores in the hydrogel, exhibiting high cytocompatibility and maintaining cell viability, proliferation, spreading, and osteogenesis in vitro. Evaluation on an experimental periodontitis rat model, using micro-computed tomography and histological analyses, demonstrated that this Mg²⁺-containing hydrogel effectively reduced periodontal inflammation, inhibited osteoclast activity, and partially repaired inflammation-induced alveolar bone loss. These results suggest that Mg²⁺-containing thermo-sensitive porous hydrogels might be promising candidates for treating periodontitis.