Verification of IL-17A and IL-17F in oral tissues and modulation of their expression pattern by steroid hormones.

Interleukin (IL-) 17A and IL-17F mediate immune responses by inducing both proinflammatory and regulatory mechanisms. Immunological processes are modulated by steroids, which also affect periodontal pathophysiology. It was the aim of this study to investigate the expression profile of IL-17A and IL-17F in periodontal tissues and to analyze the significance of testosterone and estradiol on IL-17 expression in periodontal cells. In vivo incidence of IL-17A and IL-17F was immunohistochemically quantified in human periodontal tissues. In vitro expression of IL-17A and IL-17F was analyzed in human gingival epithelial cells, gingival fibroblasts and periodontal ligament cells via qRT-PCR. Gene expression alterations of IL-17 were assessed following challenge with testosterone and 17β-estradiol under simulated inflammatory conditions (±IL-1β). Analyses proved IL-17 expression in periodontal hard and soft tissues and in resident cells, showing distinct patterns for the subtypes IL-17A and IL-17F. IL-17F was discriminatively regulated by testosterone and 17β-estradiol in resident periodontal cells.