Effect of hydrogen sulphide on the expression of osteoprotegerin and receptor activator of NF-κB ligand in human periodontal ligament cells induced by tension-force stimulation.

OBJECTIVE: Hydrogen sulphide (H2S) is an endogenous gaseous signalling molecule, the generation rate of which is affected by mechanical force in cells. Recently, it was reported that mechanical force plays an important role in some pathways such as osteoprotegerin (OPG) and the receptor activator of nuclear factor kappa B (NF-κB) ligand (RANKL) in human periodontal ligament cells (hPDLCs). Here, we investigated whether H2S played a regulatory role within the periodontal remodelling process by addressing the expression level of OPG/RANKL in hPDLCs.
DESIGN: hPDLCs were first applied with tension force for 0-120min to select the optimal time for force application. These cells were treated with H2S for 24h followed by stimulation with tension-force application. Cell proliferation and apoptosis were assessed by the methyl thiazolyl tetrazolium (MTT) assay and flow cytometry analysis. For OPG, RANKL and cystathionine-γ-lyase (CSE), real-time polymerase chain reaction (PCR) was used to analyse the messenger RNA (mRNA) expression; enzyme-linked immunosorbent assay (ELISA) was used to detect the secretion of OPG and soluble RANKL (sRANKL).
RESULTS: Tension force promoted the mRNA expression of CSE and the optimal application time was 60min. The expression of OPG was increased in a concentration-dependent manner by H2S treatment. Importantly, the relative OPG/RANKL expression ratio was significantly increased upon induction by H2S, an effect that was enhanced by tension-force application.
CONCLUSIONS: H2S could promote osteogenic differentiation by regulating the relative OPG/RANKL expression ratio of hPDLCs, which is enhanced by tension force. These findings may be valuable for understanding the mechanism of H2S in the periodontal remodelling, especially in the process of tooth movement.