Differential production of macrophage inflammatory protein-1α, stromal-derived factor-1, and IL-6 by human cultured periodontal ligament and gingival fibroblasts challenged with lipopolysaccharide from P. gingivalis

Background: Fibroblasts are considered important cells in periodontitis. When challenged by different agents, they respond through the release of cytokines that participate in the inflammatory process. The aim of this study is to evaluate and compare the expression and production of macrophage inflammatory protein (MIP)-1α, stromal-derived factor (SDF)-1, and interleukin (IL)-6 by human cultured periodontal ligament and gingival fibroblasts challenged with lipopolysaccharide (LPS) from Porphyromonas gingivalis. Methods: Fibroblasts were cultured from biopsies of gingival tissue and periodontal ligament of the same donors and used on the fourth passage. After confluence in 24-well plates, the culture medium alone (control) or with 0.1 to 10 μg/ml of LPS from P. gingivalis was added to the wells, and after 1, 6, and 24 hours, the supernatant and the cells were collected and analyzed by enzyme-linked immunosorbent assay and realtime polymerase chain reaction, respectively. Results: MIP-1α, SDF-1, and IL-6 protein production was significantly greater in gingival fibroblasts compared to periodontal ligament fibroblasts. IL-6 was upregulated in a time-dependent manner, mainly in gingival fibroblasts (P <0.05), which secreted more MIP-1α in the lowestconcentration of LPS used (0.1 μg/ml). In contrast, a basal production of SDF-1 that was inhibited with the increase of LPS concentration was detected, especially after 24 hours (P <0.05). Conclusion: The distinct ability of the gingival and periodontal ligament fibroblasts to secrete MIP-1α, SDF-1, and IL-6 emphasizes that these cells may differently contribute to the balance of cytokines in the LPS-challenged periodontium.