Boric acid alleviates periodontal inflammation induced by IL-1β in human gingival fibroblasts

Background: Boric acid (BA) has been found to have therapeutic effects on periodontal disease through beneficially affecting antibacterial, anti-viral, and anti-inflammatory actions. Methods: This study was conducted to determine the effect of BA on cell viability and on mRNA expressions of proinflammatory and anti-inflammatory cytokines and on oxidative stress enzymes induced by IL-1β (1 ng/mL) in Human Gingival Fibroblasts (HGF) cultured for 24 and 72 h in DMEM media. The BA concentrations added to the media were 0.09 %, 0.18 %, 0.37 %, and 0.75 %. Results: All of the BA concentrations increased the viability of cell cultured in DMEM media only, indicating that these concentrations were not toxic and actually beneficial to cell viability. The addition of 1 ng/m: of IL-1β decreased cell viability that was overcome by all concentrations of BA at both 24 and 72 h. The IL-1β addition to the media increased the expressions of the proinflammatory cytokines IL-1β, IL-6, IL-8, and IL-17; the anti-inflammatory cytokine IL-10; and the oxidative stress enzymes superoxide dismutase (SOD0 and glutathione peroxidase (GPX). The IL-1β induced increase mRNA expression of IL-1β was decreased at 24 h by the 0.37 % and 0.75 % BA additions to the media and decreased in a dose-dependent manner by all concentrations of BA at 72 h. The IL-1β induced increase in the expression of IL-6 was decreased in dose-dependent manner at 72 h by BA. All BA concentrations decreased the IL-1β induced expression of IL-8 at both 24 and 72 h. The induced increase in IL-17 by IL-1β was not significantly affected by the BA additions. The increase in the anti-inflammatory cytokine IL10 induced by IL-1β was increased further by all BA additions in dose dependent manner at both 24 and 72 h. The mRNA expressions of SOD and GPX increased by IL-1β were further increased by the 0.37 % and 0.75 % BA concentrations at 72 h. Conclusions: These findings indicate that BA can significantly modulate the cytokines that are involved in inflammatory stress and reactive oxygen species action and thus could be an effective therapeutic agent in the treatment of periodontal disease.