Effect of <scp>ADSCs</scp> ‐Exos on <i>Pg</i> ‐ <scp>LPS</scp> –Induced Osteoclastogenesis in an In Vitro Inflammatory Model

BACKGROUND: Periodontitis is a chronic inflammatory disorder characterized by tissue degradation and bone loss. Lipopolysaccharide (LPS) accelerates disease progression by host immune activation, inducing localized inflammatory infiltration and osteoclastogenesis, and disrupting bone metabolic homeostasis. Adipose-derived mesenchymal stem cells (ADSCs) exert anti-inflammatory, anti-apoptotic, and regenerative effects via paracrine signaling. METHODS: ADSCs were isolated using collagenase digestion and characterized by flow cytometry for surface markers and multilineage differentiation potential (assessed by Oil Red O and Alizarin Red S staining). ADSC-Exos were isolated via size-exclusion chromatography and ultrafiltration and characterized by transmission electron microscopy, nanoparticle tracking analysis, and immunoblotting. In a Pg-LPS-induced in vitro periodontitis model, PKH26-labeled ADSC-Exos were internalized by cells, as shown by confocal microscopy. Their effects on osteoclastic markers (TRAP, MMP-9, and COX-2) and signaling mediators (RANK and TRAF6) were evaluated using real-time PCR and western blotting. RESULTS: ADSCs-Exos suppressed early osteoclast differentiation in Pg-LPS-induced in vitro periodontitis model. Mechanistic studies revealed that ADSCs-Exos mitigated inflammation by modulating the COX-2/TRAF6/RANK signaling axis. CONCLUSIONS: This study investigated the effects of ADSCs-Exos on the early proliferation and differentiation of osteoclasts. Furthermore, in a periodontitis cell model, ADSCs-Exos regulate bone resorption by downregulating the mRNA and protein expression levels of COX-2, RANK, and TRAF6.