Similar protective roles have been shown in the case of FICZ (tryptophan photooxidation product 6-formylindolo[3,2-b]carbazole, a physiological ligand for the mammalian aryl hydrocarbon receptor to which it binds inducing expression of cytochrome P450) and molecules in the aryl hydrocarbon receptor axis in relation to alveolar bone loss and inflammation in experimental (murine) periodontitis (Huang et al., 2019). Here, AHR is linked to periodontitis.