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

口腔异味是由包括甲硫醇在内的挥发性硫化物(VSCs)引起的。几项研究表明，甲硫醇的数量与更多的口袋相关。此外，最近的研究表明，牙周病原菌会产生VSC。因此，提出了甲硫醇作为致病因子在牙周病的发生和发展中的作用(S)。最近的研究发现，在牙周病的深部或出血区发现了许多死亡的上皮细胞。然而，目前尚不完全清楚该细胞的细胞毒性机制。因此，我们研究了甲硫醇通过口腔上皮细胞系KB细胞诱导细胞死亡的可能性，并观察到VSC通过坏死的方式对KB细胞产生细胞毒作用。牙周病是一种以牙周炎和牙周组织中的牙槽骨吸收为特征的慢性疾病。最近的研究表明，致病菌的毒力因子，如脂多糖，能够刺激炎性细胞因子(IL-1、肿瘤坏死因子-α和IL-6)，这些细胞因子也是骨吸收的诱导者，这些细胞因子与牙周病的进展密切相关。由于这些细胞因子是由巨噬细胞大量产生的，因此细胞凋亡是炎症结束所必需的。因此，抑制巨噬细胞的凋亡加重了本病，我们用RAW 264.7细胞研究了甲硫醇对细胞凋亡的影响，观察到血管紧张素转换酶对一氧化氮诱导的细胞凋亡有强烈的抑制作用。

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.