镉毒性肾损害与镉、锌结合蛋白——Ⅰ.尿金属硫蛋白对镉毒性肾损害的检测价值

Cadmium-induced renal damage and Cd, Zn-binding proteins. I. Role of urinary metallothionein in early detecting toxic renal damage induced by cadmium.

采用Sephadex G-75凝胶柱色谱技术对亚急性镉毒性肾损害大鼠肝、肾、血、尿中金属硫蛋白(MT)进行了分离测定。结果表明,镉暴露后,肝、肾、血、尿中MT增多。MT是体内镉的主要存在形式,其在体内镉的运转、蓄积及排泄过程起最重要的作用。尿中MT增高是镉毒性肾损害最早出现的变化之一,它作为低分子蛋白质是肾小管功能障碍的灵敏指标。同时,作为一种镉金属结合蛋白,在反映镉性肾损害有其特异性。

Using a model of subacute Cd-indued renal damage of male Wistar rats treated with CdCl_2(0.592mg Cd^(2+)/kg body wt., ip., 5 times a week up th 9 weeks), metallothionein in the urine, blood and 150000g supernatants of liver and renal cortex homogenates were isolated by Sephadex G-75 column chromatography and measured by UV-AAS. Metallothionein (MT) levels in all those specimen were increased after cadmium exposure. Most of the cadmium were bound to metallothionein. These indicate that MT may play a major role in transportation, accumulation and excretion of cadmium in the body. Increase of urinary MT level was not only the earliest change of renal tubular disturbance by the appearance of low molecular weight protein, but also the specific index of Cd-induced renal damage as a Cd-binding protein.