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

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 Pb-exposed 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 ±89.46 μg/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.