Abstract: ObjectiveTo explore the combined effect of calcium and selenium on learning and memory of mice with lead exposure.MethodsTotally 36 three weeks weaning Kunming mice(clean level)were randomly divided into three groups:control, lead group,calcium and selenium combined group.Twenty days after the administration of the exposure,the water labyrinth test was conducted.The contents of lead,nitric oxide(NO)and the activites of nitric oxide synthase (NOS),inducible nitric oxide synthae(NiOS)in blood and brain tissues of the mice were also detected.ResultsThe blood lead level of the calcium and selenium combination group(469.59±58.31 μg/L)was lower than that of the lead group and higher than that of control group with significant difference(P<0.01).The cerebral NO content(8.29±1.22 μmol/g),NOS(4.39±0.98)and NiOS activity(1.65±0.28)of calcium and selenium combination group were lower than that of control group and higher than that of the lead group and the difference was statistically significant(P<0.01).The times of incubation period of water labyrinth of control group(43.8±8.9s),calcium and selenium combination group (44.1±11.7s)were shorter than that of the lead group with statistically significant difference(P<0.01).ConclusionThe combined application of calcium and selenium can effectively resist adverse effect of lead exposure in mice.