ARA290 Attenuates Apical Periodontitis via SIRT1/NF-κB/IL-1β Pathway Modulation.

INTRODUCTION AND AIMS: Existing research suggests that ARA290 may possess therapeutic potential for apical periodontitis (AP), although the mechanisms involved remain unclear. This study aims to investigate the protective effects and underlying mechanisms of ARA290 in mitigating pro-inflammatory responses of macrophages in the context of AP. METHODS: Initially, in vivo models of AP were used to assess the aberrant activation of the SIRT1/NF-κB/IL-1β signalling pathway within periapical lesions. Furthermore, the expression levels of the SIRT1/NF-κB/IL-1β signalling pathway in ARA290-treated AP models, both in vivo and in vitro, were evaluated using immunohistochemistry (IHC), Western blotting, and immunofluorescence (IF) techniques to elucidate the role of ARA290 in modulating this signalling pathway during AP pathogenesis. Subsequently, the SIRT1/NF-κB/IL-1β signalling pathway was inhibited using selisistat, and the resultant changes in inflammatory levels and bone resorption in periapical lesions were assessed through haematoxylin and eosin staining, tartrate-resistant acid phosphatase staining, IHC and micro-computed tomography (Micro CT). RESULTS: The in vivo AP model demonstrated a 50% reduction in SIRT1 expression within periapical lesions, accompanied by a 5-fold increase in the expression of acetylated NF-κB (p65) and IL-1β. Additionally, the administration of ARA290 in the AP mouse model significantly reduced inflammatory infiltration, the number of osteoclasts and the extent of bone loss in the periapical region. Notably, ARA290 treatment enhanced SIRT1 expression by approximately 40% while concurrently decreasing the levels of acetylated NF-κB (p65) by around 75% and IL-1β by approximately 62.5% in both in vivo and in vitro AP models. Importantly, inhibition of the SIRT1/NF-κB/IL-1β signalling pathway negated the beneficial effects of ARA290 in attenuating the progression of AP. CONCLUSIONS: ARA290 plays a protective role by modulating the SIRT1/NF-κB/IL-1β signalling pathway in apical periodontitis, which may provide a new direction for the adjuvant treatment of apical periodontitis.