Formation of periodontal pocket by cadmium exposure - Induction of KGF by cadmium in tobacco -

本实验通过体外培养人牙龈成纤维细胞（GF细胞）和牙龈角质形成细胞（GK细胞），用MTT比色法和DNA合成法研究了Cd对细胞的影响。MTT测定的结果显示，对于任一类型的细胞，任何Cd组（10 μ <-8>mM至10 mM）和对照组之间没有明显差异。在镉浓度为10 μ mM及以上时，DNA合成受到抑制<-6>，尽管两种类型的细胞之间的抑制程度存在差异。在上述条件下，GF细胞中IL-6和IL-8在10 μ M的Cd浓度下被诱导<-3>，而GK细胞中观察到轻微的抑制。这一结果表明GF细胞和GK细胞对Cd有不同的细胞反应。与此相反，上述细胞因子的诱导没有观察到在任何镉浓度在GK细胞。这些结果表明GF和GK细胞对Cd的反应是不同的。在GF细胞中，发现在10^至10^ mM Cd暴露48小时的10%至20%的细胞中诱导凋亡<-2><-4>。在暴露于Cd（10 μ <-3>mM）、IL-6（20 ng/mL）或LPS（E. coli，0.1 g/mL）培养24 h。在对照组细胞中不能检测到KGF-1，然而，在处理的细胞中检测到KGF-1的产生。结果表明，香烟中所含的镉对牙龈细胞有损伤作用，并促进牙周袋的形成。

The cadmium (Cd, as CdCl_2) sensitivity of human-derived gingival fibroblasts (GF cells) and gingival keratinocytes (GK cells) was studied by cultivating in media containing Cd, and assessing the effects of the Cd on the cells using an MTT assay and DNA synthesis. The results of the MTT assay revealed there were no clear differences between any of the Cd groups (10^<-8> mM to 10 mM) and the control group for either type of cell. DNA synthesis was inhibited at Cd concentrations of 10^<-6> mM and above, although there were differences in the degree of inhibition between the two types of cells. Under the above conditions, IL-6 and IL-8 were induced at a Cd concentration of 10^<-3> mM in GF cells, while in GK cells slight inhibition was observed. This result suggests that GF cells and GK cells have different cellular responses to Cd. In contrast to this, induction of the above cytokines was not observed at any Cd concentration in GK cells. These findings indicate that the cellular responses of GF and GK cells to Cd are different. In GF cells, it was found that apoptosis was induced in 10% to 20% of cells exposed to 10^<-2> to 10^<-4> mM Cd for 48 hours. The production of KGF-1 in GF cells exposed to Cd (10^<-3> mM), IL-6 (20 ng/mL), or LPS (E. coli, 0.1 g/mL) for 24 hours was also studied. KGF-1 could not be detected in control group cells, however, KGF-1 production was detected in treated cells. The highest concentration was observed in the Cd group, followed by the IL-6 group, and finally the LPS group.Based on the above results, it is believed that Cd contained in cigarettes injures gingival cells and contributes to the formation of periodontal pockets.