停止暴露后铅染毒小鼠铅负荷的恢复状况研究

Recovery of biological effects induced by lead exposure in mice after cessation of exposure

目的观察终止染铅对铅中毒小鼠各项生物学指标的影响。方法将4-6周龄清结级雄性昆明种小鼠随机分为对照组、染铅15 d A组、染铅30 d B组、染铅15 d排铅15 d C组,染铅途径为自由饮用经酸化处理的1.0 g/L三水合乙酸铅水溶液。限制小鼠日粮,分别在15 d和30 d检测小鼠血铅、骨铅及锌原卟啉水平。结果在各时间节点,各组小鼠体质量差异均无统计学意义（P〉0.05）;实验结束后,各组锌原卟啉水平差异无统计学意义（P〉0.05）。A组小鼠血铅水平为（435.73±89.46）μg/L,B组为（445.82±138.49）μg/L,两者差异无统计学意义（P〉0.05）,但两组均显著高于经排铅的C组血铅水平（149.34±27.66）μg/L。A组小鼠骨铅水平为（71.34±18.72）μg/g,B组小鼠持续染铅30 d后,骨铅上升至（114.72±31.52）μg/g,经排铅的C组骨铅水平为（80.63±21.39）μg/g,后者与A组比较差异无统计学意义（P〉0.05）,B组和A、C组比较,差异均有统计学意义（P〈0.01）。结论持续30 d染铅未导致小鼠血铅进一步升高。血铅是铅中毒小鼠脱离铅暴露环境的敏感指标。

Objective To observe the recovery of biological indicators caused by lead exposure in mice after 15-day cessation of exposure. Methods Male KM mice （cleaning grade,4-6 weeks of age） were randomly divided into 5 groups, namely, the control for 15 d,the control for 30 d,the Pb-exposed for 15 d （group A）, the Pb-exposed for 30 d （group B）,and the Pbexposed for 15 d which would recover for 15 d （group C）.The lead was exposed by drinking solution of Lead acetate trihydrate and a restricted diet was adopted. The level of blood Pb, bone Pb and ZPP was measured at the end of the test. Results Compared with the control group, blood Pb and bone Pb of the Pb-exposed groups significantly increased. But there was no difference in weight growth rate and ZPP value among these groups （P 〉 0.05）. There was no significant difference in blood Pb between group A （435.73 ± 89.46μg/L）and group B （445.82 ± 138.49 μg/L）（P 〉 0.05）,while blood Pb in group C was relatively lower （149.34 ± 27.66 μg/L）（P 〈 0.05 ）. Bone Pb in groups A, B and C was （71.34 ± 18.72）μg/g, （114.72 ± 31.52）μg/g and （80.63 ± 21.39） μg/g, respectively. Bone Pb of the group B was significantly higher compared with that of the group A and C （P 〈 0.01 ）. Conclusion These results indicated that blood lead would be stable after long lead exposure while bone Pb would continue to increase. Blood Pb is a sensitive index for the recovery of lead-exposed mice.