Physiologic Levels of Endogenous Hydrogen Sulfide Maintain the Proliferation and Differentiation Capacity of Periodontal Ligament Stem Cells

Background: Many invading oral bacteria are known to produce considerable amounts of hydrogen sulfide (H2S). The toxic activity of exogenous H2S in periodontal tissue has been demonstrated, but the role of endogenous H2S in the physiologic function of periodontal tissue remains poorly understood. The purpose of the present study is to investigate the biologic functions of H2S in the proliferation and differentiation of human periodontal ligament stem cells (PDLSCs).Methods: PDLSCs were isolated from periodontal ligament tissues of periodontally healthy volunteers or patients with periodontitis. Immunocytochemical staining, flow cytometry, and Western blot analysis were used to examine the expression of H2S-synthesizing enzymes cystathionine-β-synthase (CBS) and cystathionine-γ-lyase (CSE). The proliferation capacity of PDLSCs was determined by cell counting kit-8 assay, carboxyfluorescein succinimidyl ester analysis, and 5-ethynyl-2′-deoxyuridine assay. The osteogenic potential of PDLSCs was tested using ...