镉金属硫蛋白的毒性研究—金属毒理学研究中的一个热点

镉金属硫蛋白(Cd-Mt)是接触镉的生物体内镉存在的主要形式。它在体内的分布、转运和贮存有不同于Cd~(++)的许多特点,肾脏毒性远大于Cd的无机化合物。目前许多研究已阐明,Cd-Mt是镉吸收后由肝向肾损转移的主要形式,它可经肾小球滤过,但能迅速经肾管小管再吸收,并造成镉特有的以肾小管损伤为主的病变。至于Cd-Mt肾损害的机理,目前尚无一致意见,正在进一步深入究究。阐明这一问题,不仅能明确镉中毒的机理,并可进一步弄清金属硫蛋白的作用,对金属毒理学的研究至关重要。

Toxicological Study on Cd-Mt and the Pathogenesis of Nephropathy Induced by Cadmium

It is obvious that cadmium bound to metallothionein ( Cd-Mt ) might play an important role in cadmium toxicity. The distribution, transportation and storage of Cd-Mt have different proberties from those of Cd2+. Nephrotoxicity of Cd-Mt is about 10 times higher than that of CdCl2. Tubular epithelial cell necrosis is the major pathological changes, Cd-Mt can be easily filtrated through glomerulus and reabsorpted by proximal tubular cells. Cd-Mt induced renal damage primarily occurs during the uptake of Cd-Mt by pinocytosis into the cell and subsequent cytotoxic effects. The Cd-induced hepa totoxicity causes leakage of Cd-Mt from liver and hepatic injury may be the prerequisite of the renal damages. The studies on Cd-Mt toxicity start a new way to understand the pathogenesis of cadmium toxicity. It makes possible to explain the nephrotoxicity with hepatotoxicity and even the whole body.