Vitamin D modulatory effect on cytokines expression by human gingival fibroblasts and periodontal ligament cells

BACKGROUND: It has been demonstrated that vitamin D exerts several functions other than those implied in the bone homeostasis. It has been published the vitamin D can act on many cells and tissues behaving also as a modulatory factor in the immune responses. The aim of our study was to evaluate the effect of active vitamin D3 (VD) on the expression of pro-inflammatory and anti-inflammatory cytokines (IL-6, IL-8, IL-10 and IL-12) in human gingival fibroblasts (hGF) and human periodontal ligament cells (hPDLc) triggered by Porphyromonas gingivalis and Streptococcus pyogenes. METHODS: Primary hGF and hPDLc pretreated or not by VD (10(-8) mol/L) were exposed to P. gingivalis and S. pyogenes for 24 h. Production of IL-6, IL-8, IL-10 and IL-12 was evaluated by immunoenzymatic assay. mRNA of the same cytokines were evaluated by PCR. RESULTS: IL-6 secretion increased by 25.2% (+/- 2.1) up to 51% (+/- 3.3) in VD treated hGF and hPDLc exposed to P. gingivalis and S. pyogenes, compared to VD not treated cells. IL-8 secretion decreased approximately by 30% in VD-treated hGF and hPDLc compared to VD not-treated cells. IL-12 secretion decreased by 60%. On the contrary, anti-inflammatory cytokine IL-10 increased by approximately 200%. mRNA PCR confirmed these results. CONCLUSIONS: Within the limits of the study, the obtained results support the hypothesis of a modulatory role of VD on periodontal cells exposed to bacterial infection, reducing their inflammatory response and increasing the secretion of anti-inflammatory and modulatory cytokines. Consequently, it could be speculated that vitamin D assessment, and its possible implementation in deficiency cases, could play a role in periodontal treatment.