Interleukin-35 inhibits alveolar bone resorption by modulating the Th17/Treg imbalance during periodontitis.

Cafferata, Emilio A; Terraza-Aguirre, Claudia; Barrera, Romina; Faúndez, Nicolás; González, Nicolás; Rojas, Carolina; Melgar-Rodríguez, Samanta; Hernández, Marcela; Carvajal, Paola; Cortez, C; González, Fermín E; Covarrubias, Cristian; Vernal, R

AIM T lymphocytes play a central role during the pathogenesis of periodontitis, and the imbalance between the pathogenic T-helper type 17 (Th17) and protective T-regulatory (Treg) lymphocytes determines the tooth-supporting alveolar bone resorption. Interleukin (IL)-35 is a novel anti-inflammatory cytokine with therapeutic properties in diseases whose pathogenesis is associated with the Th17/Treg imbalance; however, its role during periodontitis has not been established yet. This study aimed to elucidate whether IL-35 inhibits the alveolar bone resorption during periodontitis by modulating the Th17/Treg imbalance. MATERIALS AND METHODS Mice with ligature-induced periodontitis were treated with locally or systemically administrated IL-35. As controls, periodontitis-affected mice without IL-35 treatment and non-ligated mice were used. Alveolar bone resorption was measured by micro-computed tomography and scanning electron microscopy. The Th17/Treg-pattern of the immune response was analyzed by qPCR, ELISA, and flow cytometry. RESULTS IL-35 inhibited alveolar bone resorption in periodontitis mice. Besides, IL-35 induced less detection of Th17 lymphocytes and production of Th17-related cytokines, together with higher detection of Treg lymphocytes and production of Treg-related cytokines in periodontitis-affected tissues. CONCLUSION IL-35 is beneficial in the regulation of periodontitis; particularly, IL-35 inhibited alveolar bone resorption and this inhibition was closely associated with modulation of the periodontal Th17/Treg imbalance.