Effects of hydrogen sulfide on the expression of alkaline phosphatase, osteocalcin and collagen type I in human periodontal ligament cells induced by tension force stimulation

Periodontal ligament cells (PDLCs) are important in homeostasis and remodeling in the mechanically-stimulated periodontium. The aim of the present study was to investigate the effects of hydrogen sulfide (H2S) on periodontal tissue remodeling by examining the mRNA and protein expression levels of alkaline phosphatase (ALP), osteocalcin (OCN) and collagen type I (COL-1) in human (h)PDLCs induced by tension force application. Cultured hPDLCs were treated with H2S for 24 h, followed by application of a tension force for 1, 3 and 6 h. Cell proliferation and apoptosis were determined using a Cell Counting Kit 8 assay and flow cytometric analysis, respectively. The mRNA expression levels of ALP, OCN and COL-1 were quantified using reverse transcription-quantitative polymerase chain reaction analysis, and western blot analysis was used to detect the protein levels of ALP, OCN and COL-1. The results demonstrated that the mRNA and protein expression levels of ALP, OCN and COL-1 increased with H2S treatment in a concentration-dependent manner, which was enhanced by the application of tension force in a relatively short period of time. These findings suggested that H2S may be important in periodontal tissue remodeling during orthodontic tooth movement via increasing hPDLC differentiation, tissue mineralization, bone formation and collagen synthesis.