Lin Tian, Tai-Yi Jin
Department of Occupational and Environmental Health, School of Public Health and Family Medicine, Capital Medical University, Peijing, PR China.
Environ Toxicol. 2007 Jun;22(3):229-33. doi: 10.1002/tox.20260.
Benchmark dose (BMD) and the lower confidence limit on the benchmark dose (BMDL) of blood lead were estimated to explore the biologic exposure limits for renal dysfunction caused by lead. One hundred thirty-five workers from one storage battery plant were selected as lead exposure group while 143 mechanics as the control. The relationship between the blood lead concentration and the urinary excretion of total protein (TP), beta2-microglobulin (beta2-MG), and N-acetyl-beta-D-glucosaminidase (NAG) was studied. The quantal linear logistic regression model (BMDS Version 1.3.1) was used to calculate BMD and BMDL of blood lead. The results showed that the levels of NAG, beta2-MG, and TP in lead-exposed workers were higher than those of control group and elevated along with rising length of employment. The levels of three indices for renal dysfunction increased with the elevated blood lead. The BMD and BMDL of blood lead for renal dysfunction were from 299.4 to 588.7 microg/L and from 253.4 to 402.3 microg/L, respectively. The BMDL of blood lead was ranged from high to low as TP, beta2-MG, and NAG. It is suggested that the urinary NAG activity could be a sensitive and early biomarker of renal tubular dysfunction induced by lead. When assessing renal function in workers occupationally exposed to lead, a blood lead level of 250 microg/L could serve as a warning signal.
估算血铅的基准剂量（BMD）和基准剂量下限（BMDL），以探索铅所致肾功能障碍的生物暴露限值。选取一家蓄电池厂的135名工人作为铅暴露组，143名机械师作为对照组。研究血铅浓度与总蛋白（TP）、β2-微球蛋白（β2-MG）和N-乙酰-β-D-氨基葡萄糖苷酶（NAG）尿排泄量之间的关系。采用定量线性逻辑回归模型（BMDS 1.3.1版）计算血铅的BMD和BMDL。结果显示，铅暴露工人的NAG、β2-MG和TP水平高于对照组，且随着就业年限的增加而升高。肾功能障碍的三项指标水平随血铅升高而增加。肾功能障碍血铅的BMD和BMDL分别为299.4至588.7μg/L和253.4至402.3μg/L。血铅的BMDL从高到低依次为TP、β2-MG和NAG。提示尿NAG活性可能是铅所致肾小管功能障碍的敏感早期生物标志物。在评估职业性铅暴露工人的肾功能时，血铅水平250μg/L可作为一个警示信号。
