Aspirin loaded extracellular vesicles inhibit inflammation of macrophages via switching metabolic phenotype in periodontitis

Changes of macrophage in the local immune microenvironment of periodontitis cause alveolar bone resorption. This study aims to investigate the effect of a new drug delivery method of aspirin on the immune microenvironment of periodontitis to promote alveolar bone repair, and to explore mechanism of aspirin's effect on macrophage.We isolated extracellular vesicles (EVs) from periodontal stem cells (PDLSCs) and loaded with aspirin by sonication, and then evaluated the treatment efficacy of aspirin-loaded vesicles (EVs-ASP) in periodontitis model in mice. In vitro, we explored the role of EVs-ASP in the regulation of LPS-induced macrophages. The underlying mechanism by which EVs-ASP regulates phenotypic remodeling of macrophages in periodontitis was further investigated.EVs-ASP inhibited the inflammatory environment of LPS-induced macrophage, and promoted anti-inflammatory macrophages formation both in vivo and in vitro, and reduced bone loss in periodontitis models. Moreover, EVs-ASP enhanced oxidative phosphorylation and suppressed glycolysis in macrophages.Consequently, EVs-ASP improves the periodontal immune microenvironment by enhancing oxidative phosphorylation (OXPHOS) in macrophages, resulting in a certain degree of regeneration of alveolar bone height. Our study provides a new potential strategy for bone repair in periodontitis therapy.