环境镉接触人群尿金属硫蛋白排泄与镉致骨损伤效应

目的研究环境镉接触人群尿金属硫蛋白(UMT)的排泄与镉致骨损伤效应的关系。方法镉污染区居民为环境镉接触人群,非污染区居民为对照人群。人群尿镉(UCd)与血镉(BCd)用原子吸收分光光度法测定,用环境接触量估测总镉摄入量(TCd)。UMT、尿β2微球蛋白(UB2M)、尿视黄醇结合蛋白(URBP)及尿白蛋白(UALB)用ELISA法测定,尿N-乙酰-β-D-氨基葡萄糖苷酶(UNAG)和UNAG同工酶B(UNAGB)用荧光分析法测定,均用尿肌酐校正。单光子骨密度仪测定人群前臂骨密度。结果UMT能反映机体接触镉时镉负荷的变化。而高剂量接触镉可先后导致肾功能障碍及骨质疏松。人群UMT排泄量与骨密度的关系同UMT排泄量本身是否异常有关。根据各指标与尿镉的剂量-反应曲线计算得到的基准剂量95%低限水平BMDL值,从小到大排列为UNAGB、UNAG、UB2M、UMT、URBP、T评分及UALB。结论镉致骨质疏松的发生与镉致肾功能障碍有关并迟于后者。UMT不仅能特异而敏感的反映镉致肾的毒性,而且能在一定程度上反映镉对骨骼的损伤。

Excretion of urinary metallothionein and osteal damage induced by cadmium in an environmentally cadmium exposed population

Objective To observe the relationship between urinary metallothionein excretion and osteal damage induced by cadmium in a general population. Methods The inhabitants living in both cadmium polluted and non-polluted areas were asked to participate in this study. Urinary cadmium (UCd) and blood cadmium(BCd) were measured by GF-AAS. Total cadmium(TCd)was evaluated with environmental cadmium exposure. URBP, UB2M, UALB and UMT were measured by ELISA method. UNAG,UNAGB were measured by fluorescence analysis method. Forearm bone mineral density in human were mensurated by SPA. Results UMT can reflect the change of cadmium body burden. Renal dysfunction and osteoporosis would appear successively after high level of cadmium exposure. UMT had a complex relationship with bone mineral density which related to the amount of UMT excretion. The BMDLs of UCd were calculated using software of BMDS Version1.3.2 for these biomarkers. The values of BMDL of these biomarkers were arranged: UNAGB