锰暴露致人体外周铁代谢的失衡

目的通过研究锰暴露人群外周铁代谢的变化，探讨锰暴露对作业工人外周铁代谢的影响。方法全部实验对象均来自北京同一单位，暴露组为从事手工电弧焊作业的97名工人（使用焊条为J422型），对照组为非有害作业工人91名；按照国家标准规定的方法对锰暴露者工作场所空气中的锰浓度进行了采样分析；采用石墨炉原子吸收法检测血清锰、血清铁，应用双扰夹心酶联免疫的方法检测血清铁蛋白、转铁蛋白、转铁蛋白受体的浓度。结果3个锰暴露工作场所空气中锰的PC-STEL范围是0．53-2．19mg／m^3，PC-TWA范围是0．29～0．92mg/m^3。暴露组血清转铁蛋白、血清铁、血清锰浓度均高于对照组，差异有统计学患义（P〈0．05，P〈0．01，P〈0．01），而暴露组血清转铁蛋白受体明显低于对照组（P=0．01），虽然血清铁蛋白水平两组比较差异无统计学意义（P〉0．05），但暴露组铁蛋白水平有升高的趋势；暴露组血清铁和血清锰异常率分别是55.67％和67.01％，与对照组异常率比较差异有统计学意义，且暴露组血清转铁蛋白含量异常率也有升高的趋势。单因素方差分析显示，各项指标的变化趋势随着锰暴露工龄的增加而变化，未发现各生物指标与锰暴露时间的线性相关关系（P〉0．05）。结论长期锰暴露可导致铁代谢的失衡，表现在血清铁、转铁蛋白的增高和血清转铁蛋白受体的下降。

Altered Systemic Iron Metabolism in Welders Exposed to Manganese

Objective To investigate the systemic changes of iron metabolism following manganese exposure. Methods Ninety-seven welders and 91 workers with no history of exposure to manganese were recruited from the same factory in Beijing serving as the exposure group and the control group respectively.The welding rods used were type J422. The concentration of the manganese in the air of the work place was determined respectively with the national standard method. The serum iron and manganese, ferritin, transferrin and transferrin receptors were measured with the graphite furnace atomic absorption spectrophotometry and ELISA in both groups. Results The permissible concentration-STEL of ambient Mn in welders' breathing zone ranged from 0.53 mg/m3 to 2.19 mg/m3, while the permissible concentration-TWA of ambient Mn was between 0.29 mg/m and 0.92 mg/m in the breathing zone of the workplace. Serum Mn and Fe concentrations in welders were about 1.40 times (P<0.01) and 1.2 times (P<0.01), respectively, higher than those of control subjects. At the same time, the transferrin concentrations in serum were significantly higher (about 1.2 times, P<0.05) in welders than in controls. In contrast, transferrin receptors were significantly lower (about 1.2 times) in exposed subjects than controls (P=0.001). There was no difference in serum ferritin between the two groups (P=0.112).Although there was no significant trend, the serum ferritin level was increased by 18% in comparison with that of the control.The abnormal percentage of serum Fe and Serum Mn in welders were 55.67 % and 67.01 % respectively, higher than those of control subjects. In addition, the correlations between all indicators and the duration of employment were not observed. Conclusion The long term exposure to the manganese can induce the disorder of the iron metabolism, which is found in the expression of increase of the serum iron and transferrin as well as the decrease of transferrin receptors.