Mechanical Gingival Stimulation Increased Osteogenesis In Inflamed Periodontal Ligaments Cells

There are clinical concerns about excessive force and bone remodelling in periodontitis patients. Mechanical priming of the cells enhances its stem cell and osteogenic potential, but the modulation of inflammation or bone remodeling remain unclear. This study investigated the effect of human gingival fibroblasts (hGF) receiving mechanical shear force on human periodontal ligament cells (hPDL). Primary hGFs and hPDLs were derived from extracted 3rd molar (n=3) to mimic bacterial and non-bacterial inflammation, PG-LPS and cytokine cocktail (CC) of IL-1β 1ng/mL, TNF-a 10 ng/mL and IFN-ɣ 100 ng/mL were treated on hPDLs for 24 hours. The conditioned medium of hGFs that received force from shear force apparatus at 500 RPM for 6 hours were collected and transferred to the LPS/CC treated hPDLs and were incubated 24 hrs. Cells were treated under osteogenic condition. RT-qPCR and mineralization assay were performed. The result showed increased of COL1A1 in hGFs and decrease inflammatory gene expression, while no significant differences were observed in inflammation-related genes in hPDLs treated with conditioned medium. After treatment with OM for 14 days, ALP expression in hPDLs showed no difference, while RUNX2 showed upregulation in the PG-LPS-pretreated group. The mineralization assay showed increased mineralization in both hPDL with PG-LPS or CC. In healthy hPDL, mechanical shear forces on hGF did not activate osteogenic activity or inflammation. In inflamed hPDL, mechanical priming promoted osteogenic activity but did not reduce periodontal inflammation either by bacterial or non-bacterial related.