Besides, AhR activation by several endogenous ligands, including 6-Formylindolo(3,2-b)carbazole (FICZ), kynurenine and 1,25-dihydroxyvitamin D3 (VD3), could inhibit the NF-κB signaling pathway and reduce IL-1β expression in periodontitis, glioblastoma and colitis (Yu et al. 2018; Takenaka et al. 2019; Li et al. 2019). This evidence concerns the gene AHR and periodontitis.