Importance and functional rotes of methylmercaptan, one of the main causes of oral malodor, in induction or progression of adult periodontal disease

口腔恶臭是由挥发性含硫化合物（VSC），包括甲基苯丙胺。一些研究表明，甲基苯丙胺的含量与更深的口袋有关。另外，最近的研究表明，牙周病细菌产生的VSC。近年来的研究发现，在牙周病的深部或出血区，有大量死亡的上皮细胞，这些细胞在牙周病的发生、发展过程中起着重要的作用。然而，它是不知道的细胞毒性机制，完全。因此，我们通过口腔上皮细胞株KB细胞研究了甲基强的松龙诱导细胞死亡的可能性，并观察到VSC通过坏死的方式对KB细胞产生细胞毒性作用。牙周病是一种以牙龈炎症和牙周组织牙槽骨吸收为特征的慢性疾病。近年来的研究表明，致病菌的毒力因子脂多糖（lipopolysaccharide，LPS）能够刺激炎症细胞因子IL-1、TNF-α和IL-6的产生，这些炎症细胞因子也是骨吸收的诱导因子，与牙周病的进展密切相关。由于巨噬细胞大量产生这些细胞因子，因此细胞凋亡是炎症结束的必要条件。因此，我们认为抑制巨噬细胞凋亡是本病的重要因素。我们用Raw 264.7细胞观察了甲基强的松龙对细胞凋亡的影响，发现VSC强烈抑制一氧化氮诱导的细胞凋亡。

Oral malodor is caused by volatile sulfur compounds (VSCs) including methylmercaptan. Several studies showed that amount of methylmercaptan are correlated with deeper pockets. In addition, resent studies show that periodontopathic bacteria produce the VSC. Therefore, it is proposed us that methylmercaptan plays a functional role (s) as pathogen factor for induction and progression of periodontal disease.Resent studies have investigated that many dead epithelial cells are detected in the area of deeper or bleeding pockets. However, it is not known the cytotoxic mechanisms of the cells, completely. And so, we examine a possibility that methylmercaptan induces the cell death via using oral epithelial cell line KB cells and observed that the VSC exhibits cytotoxic effect on KB cells via necrosis manner.Periodontal disease is a chronic disease characterized by inflammation of gingival and resorption of alveolar bone in periodontal tissues. Resent studies indicated that virulence factors of pathogenic bacteria, such as lipopolysaccharide (LPS), are able to stimulate inflammatory cytokines (IL-1, TNF-α, and IL-6), which are also inducers of bone resorption, and then, these cytokines closely contribute to progression of periodontal disease. Since these cytokines is abundantly produced by macrophage, the cellular apoptosis is requisite for the end of inflammation. Therefore, it is suggested that inhibition of the apoptosis of macrophage aggravates this disease, and we investigated effect of methylmercaptan on the cellular apoptosis vie using Raw 264.7 cells and observed that the VSC strongly inhibit nitric oxide-induced the apoptosis.