Satoh Masahiko, Koyama Hiroshi, Kaji Toshiyuki, Kito Hideaki, Tohyama Chiharu
Environmental Health Sciences Division, National Institute for Environmental Studies, Tsukuba 305-8506, Onogawa, Japan.
Tohoku J Exp Med. 2002 Jan;196(1):23-32. doi: 10.1620/tjem.196.23.
Since there are a plethora of studies on cadmium toxicity and poisoning in laboratory animals and humans, we have limited this review to studies that are relevant to human health issues by focusing on carcinogenicity, genotoxicity, circulatory disease, nephrotoxicity and life expectancy. Cadmium exposure has been established to induce cancer in various tissues of laboratory animals. Contrary to early findings of the lack of genotoxicity by cadmium, recent findings of mammalian cell culture studies have revealed genotoxic effects. Furthermore, cadmium exposure at relatively low doses induces circulatory diseases in laboratory animals. Despite such results of various cadmium toxicities in animal studies, data from human studies are lacking and insufficient to support the cause-effect relationship. Although cadmium is currently considered to be a human carcinogen by the International Agency for Research and Cancer, it is inappropriate to conclude that sufficient evidence on the carcinogenicity of cadmium in humans exists. It is also thought that epidemiological studies so far reported do not support the occurrence of cadmium-induced circulatory disease in humans. Since there are inconsistent reports on the relationship of cadmium exposure with the life expectancy of people living in cadmium-polluted areas, further studies are needed for clarification. It is also necessary to examine apparent discrepancies in result between humans and experimental animals. It has been established that long-term exposure to cadmium causes renal dysfunction in both humans and experimental animals, and whether there are any differences in the inducibility of metallothionein in the kidney warrants further study.
由于关于实验室动物和人类镉毒性及中毒的研究众多，我们将本综述限定为通过关注致癌性、遗传毒性、循环系统疾病、肾毒性和预期寿命等与人类健康问题相关的研究。已证实镉暴露会在实验室动物的各种组织中诱发癌症。与早期关于镉缺乏遗传毒性的研究结果相反，哺乳动物细胞培养研究的最新发现揭示了镉的遗传毒性作用。此外，相对低剂量的镉暴露会在实验室动物中诱发循环系统疾病。尽管动物研究中有各种镉毒性的此类结果，但人类研究的数据匮乏且不足以支持因果关系。虽然国际癌症研究机构目前认为镉是人类致癌物，但得出镉对人类致癌性存在充分证据的结论是不合适的。还认为迄今为止报道的流行病学研究不支持人类中发生镉诱导的循环系统疾病。由于关于镉暴露与镉污染地区居民预期寿命之间关系的报道不一致，需要进一步研究以澄清。还需要研究人类和实验动物之间结果的明显差异。已证实长期接触镉会导致人类和实验动物出现肾功能障碍，肾脏中金属硫蛋白的诱导能力是否存在差异值得进一步研究。
