α-tocopherol decreases interleukin-1β and -6 and increases human β-defensin-1 and -2 secretion in human gingival fibroblasts stimulated with Porphyromonas gingivalis lipopolysaccharide

Abstract

Background and objective: Periodontitis, a disease associated with chronic inflammation, results in significant destruction of periodontal tissues. Uncontrolled, periodontal disease negatively affects general patient health. We sought to evaluate the effect of α-tocopherol on gingival fibroblast behavior following exposure to Porphyromonas gingivalis lipopolysaccharide (LPS).

Material and methods: Primary human gingival fibroblasts were cultured for 24 and 48 h with α-tocopherol at various concentrations (0, 50, 100 and 200 μm) in the presence or absence of 1 μg/mL of LPS. At the end of each time point, cell adhesion and growth were evaluated by means of optical microscope observations and MTT assay. The secretion levels of cytokines interleukin (IL)-1β and IL-6 and human β-defensins 1 and 2 were measured by specific enzyme-linked immunosorbent assay. Finally, an in vitro scratch wound assay was performed to investigate the effect of α-tocopherol on fibroblast migration.

Results: α-tocopherol alone had no adverse effect on cell adhesion and morphology. Fibroblast proliferation increased in the presence of α-tocopherol with and without LPS. α-tocopherol alone had no effect on inflammatory cytokine (IL-1β and IL-6) secretion. Interestingly, following cell exposure to P. gingivalis LPS, α-tocopherol significantly (p < 0.01) decreased the secretion of these two cytokines and increased human β-defensin-1 and -2 secretion. Finally, α-tocopherol increased the healing rate of the gingival fibroblasts from 12 h up to 48 h.

Conclusion: These results suggest that α-tocopherol may play an active role in countering the damaging effect of LPS by reducing inflammatory cytokines, increasing β-defensins and promoting fibroblast growth, migration and wound healing.

Keywords: cytokines; gingival fibroblasts; lipopolysaccharide; wound healing; α-tocopherol; β-defensins.