PPAR-γ Inhibits Chronic Apical Periodontitis by Facilitating Macrophage Efferocytosis

This study aimed to elucidate the role of peroxisome proliferator-activated receptor-γ (PPAR-γ) in regulating macrophage efferocytosis during the pathogenesis of chronic apical periodontitis (CAP). Clinical specimens, rat periapical lesion models, and an in vitro model simulating the CAP inflammatory milieu were employed to examine the contribution of PPAR-γ to efferocytosis throughout disease progression. The expression of PPAR-γ in vivo was assessed by single-cell RNA sequencing and immunohistochemical (IHC) staining. Pearson's correlation and linear trend tests were conducted to investigate the association between PPAR-γ and macrophage efferocytosis during CAP progression. Pharmacological modulation of PPAR-γ was further conducted using rosiglitazone (RSG) as an agonist and GW9662 as an antagonist, followed by an assessment of efferocytosis-related parameters and inflammatory responses. Both clinical specimens and animal models demonstrated a progressive reduction in PPAR-γ expression and macrophage efferocytosis during CAP. Notably, PPAR-γ attenuated efferocytosis impairment and significantly reduced pathogen-induced inflammatory responses in macrophages. These findings indicate that defective macrophage efferocytosis contributes to the exacerbation of CAP severity, whereas targeting PPAR-γ may represent a promising therapeutic strategy to alleviate inflammation in periapical lesions by restoring efferocytic capacity. Collectively, this study highlights PPAR-γ as a potential therapeutic target warranting further investigation in CAP treatment.