Expression of antimicrobial peptides and interleukin-8 during early stages of inflammation: An experimental gingivitis study.

ABSTRACT

BACKGROUND AND OBJECTIVES: In the oral cavity, the epithelial surface is constantly exposed to a number of different microorganisms that are organized in a well-structured biofilm. The aim of this study was to monitor gingival expression of antimicrobial peptides (AMPs) and interleukin-8 (IL-8) in an early gingivitis model. MATERIAL AND METHODS: Experimental gingivitis was allowed to develop in healthy volunteers (n = 17). Bleeding on probing (BOP%) and gingival crevicular fluid volume (GCF) were assessed at baseline and day 1, 3, 5, 7 and 14. Expression of AMPs (human beta-defensin-2, hBD-2; CC-chemokine ligand 20, CCL20; psoriasin, pso/S100A7) and IL-8 was analyzed by immunohistochemistry in gingival biopsies. In addition, hBD-2 and IL-8 protein expression was monitored in GCF using the ELISA technology. RESULTS: Experimental gingivitis gradually developed with an increase in BOP scores and GCF volume over time. In GCF, elevated concentrations of hBD-2 and IL-8 were monitored at day 1, 5 and 7 (p ≤ 0.0002). Immunohistochemical analysis of gingival sections demonstrated increased staining for hBD-2 at day 3, whereas the CCL20, pso/S100A7, and IL-8 expression was increased at later time points (p < 0.05). CONCLUSION: For the first time, this study showed the time-dependent regulation of AMPs, following clinical signs of experimentally induced gingival inflammation. Differential temporal expression for AMPs may ensure a constant antimicrobial activity against changes in the bacterial composition of the growing dental biofilm.