Ammonia Induced Macrophage Death Aggravates Periodontitis

Ammonia accumulation disrupts immune homeostasis and induces cell death. however, its role in the progression of periodontitis remains largely unclear. This study aimed to investigate whether ammonia-induced macrophage death contributes to the progression of periodontitis. Gingival crevicular fluid (GCF) was collected from periodontitis patients and healthy controls to quantify ammonia levels. An in vitro inflammatory model was established using LPS-stimulated rat bone marrow-derived macrophages. NH₄Cl was subsequently used to induce intracellular ammonia accumulation. Cell proliferation and viability were assessed via CCK-8 and live/dead staining. The expression of ammonia transporters (RHAG, RHBG, RHCG), autophagy markers (LC3, P62), and pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) was assessed using qRT-PCR, Western blotting, and ELISA. All procedures were approved by the institutional Ethics Committee. GCF from periodontitis patients showed significantly higher ammonia concentrations than the controls. NH₄Cl treatment led to intracellular ammonia buildup, increased expression of ammonia transporters, impaired autophagic flux, reduced cell proliferation, and elevated cytokine expression under inflammatory conditions. These findings indicate that ammonia induces a distinct form of macrophage cell death associated with autophagy disruption, potentially contributing to the progression of periodontitis. Targeting ammonia metabolism in macrophages may provide a novel therapeutic strategy for periodontal disease.