Interleukin-17 receptor antagonist reduces inflammatory response in experimental periodontitis

Aim or Purpose: Interleukin (IL)-17 is one of the inflammatory cytokines caused periodontitis and psoriasis. Psoriasis, a chronic inflammatory skin disease, treats with IL-17 receptor antagonist (brodalumab: BRD). However, little is known about the effect of BRD on periodontitis. This study was evaluated the inhibitory effect of BRD on experimental periodontitis. In addition, we determined the bacterial growth inhibitory effect against Porphyromonas gingivalis (Pg) and inhibitory effect of inflammatory cytokine production in vitro. Materials and Methods: Three-week-old, male, BALB/c mice were orally infected with Pg. BRD was intraperitoneally administered every two days. Fifteen days after the starting of BRD administration, alveolar bone resorption of maxillary samples was evaluated by the distance between cemento-enamel junction and alveolar bone crest, and histopathological examination. To determine the influence of BRD on Pg growth, Pg was inoculated into the bacterial broth containing its antagonist and evaluated the adenosine triphosphate (ATP) activity using a luminometer. The inhibitory effect of inflammatory cytokine production by BRD were analyzed by quantitative polymerase chain reaction. The experimental procedures of this study were approved by the Committee of Ethics on Animal Experiments of Kanagawa Dental University. Results: The volume of alveolar bone resorption was decreased in a concentration-dependent manner. The number of neutrophils and osteoclasts decreased by its administration. The volume of ATP in bacterial broth containing BRD showed a quarter of Pg only cultivation. BRD also reduced the levels of gene expressions on IL-1β, IL-6 and IL-17. These results showed that BRD caused healing of bone and suppressed inflammatory response. Conclusions: Our findings suggest that BRD promotes the prevention of periodontiti