Lau J C, Jackson-Boeters L, Daley T D, Wysocki G P, Cherian M G
Department of Pathology, University of Western Ontario, Ont., N6A 5C1, London, Canada.
Arch Oral Biol. 2001 Nov;46(11):1015-20. doi: 10.1016/s0003-9969(01)00069-3.
Amalgam tattoos occur when small particles of dental amalgam, composed largely of silver (Ag) and mercury (Hg), are inadvertently implanted into oral soft tissues during dental procedures. Metallothioneins (MTs) are ubiquitous, low molecular weight, cysteine-rich, metal-binding proteins that are inducible by many agents including metals and may be involved in the detoxification of toxic metals such as Hg. In this study, the correlation between MT expression and amalgam tattoos in human gingiva was investigated using energy-dispersive X-ray microanalysis (EDX) and immunohistochemical techniques. Light microscopically, amalgam tattoos presented as either fine granular particles or larger discrete opaque globular particles in connective tissues. EDX revealed the smaller particles to be silver sulphide (Ag(2)S), while the larger particles exhibited a shell of Ag(2)S that contained irregularly distributed masses of Ag and Hg. Particles of tin (Sn) were also found. No MT staining was observed in collagen, fibroblasts or blood vessels in areas exhibiting abundant amounts of embedded fine granular Ag(2)S particles. Blood vessels exhibiting relatively few amalgam particles stained positively for MT. Cells with the morphological features of histiocytes located directly adjacent to larger pieces of amalgam showed intense MT staining. These results indicate that amalgam tattoos contain no Hg or free Ag except in large globular pieces of amalgam, which still contain Hg and which induce MT expression in adjacent histiocytes. This suggests that Hg leaching from impacted dental amalgam particles induces MT, while residual Ag(2)S and Sn particles do not. MT may therefore act to reduce Hg exposure in patients with amalgam tattoos.
银汞合金纹身是指在牙科治疗过程中，由主要含银（Ag）和汞（Hg）的牙科银汞合金的小颗粒意外植入口腔软组织而形成的。金属硫蛋白（MTs）是普遍存在的、低分子量、富含半胱氨酸的金属结合蛋白，可被包括金属在内的多种物质诱导产生，可能参与汞等有毒金属的解毒过程。在本研究中，使用能量色散X射线微分析（EDX）和免疫组织化学技术研究了人牙龈中MT表达与银汞合金纹身之间的相关性。光学显微镜下，银汞合金纹身在结缔组织中表现为细颗粒状或较大的离散不透明球状颗粒。EDX显示较小的颗粒为硫化银（Ag₂S），而较大的颗粒呈现出一层Ag₂S外壳，其中含有不规则分布的Ag和Hg团块。还发现了锡（Sn）颗粒。在显示大量嵌入细颗粒状Ag₂S颗粒的区域，胶原、成纤维细胞或血管中未观察到MT染色。银汞合金颗粒相对较少的血管MT染色呈阳性。直接毗邻较大银汞合金块的具有组织细胞形态特征的细胞显示出强烈的MT染色。这些结果表明，除了大球状银汞合金块中仍含有Hg并在相邻组织细胞中诱导MT表达外，银汞合金纹身中不含Hg或游离Ag。这表明从受影响的牙科银汞合金颗粒中浸出的Hg诱导MT，而残留的Ag₂S和Sn颗粒则不会。因此，MT可能起到减少银汞合金纹身患者Hg暴露的作用。
