Potential association of lead exposure during early development of mice with alteration of hippocampus nitric oxide levels and learning memory.
OBJECTIVE
Chronic lead (Pb) exposure during development is known to produce learning deficits. Nitric oxide participates in the synaptic mechanisms involved in certain forms of learning and memory. This study was designed to clarify whether Pb-induced impairment in learning and memory was associated with the changes of nitric oxide levels in mice brains.


METHODS
Sixty Balb/c mice aged 10 days were chosen. A model of lead exposure was established by drinking 0.025%, 0.05%, 0.075% lead acetate, respectively for 8 weeks. The controls were orally given distilled water. The ability to learn and memorize was examined by open field test, T-water maze test. In parallel with the behavioral data, NO level of hippocampus tissue was detected by biochemical assay.


RESULTS
Compared with control groups, (1) the weight of 0.075% group was significantly reduced (P<0.05); (2) The number of times in mice attaining the required standards in T-water maze test was lower in 0.075% group (P<0.01). No significant difference was found between experimental and control groups in open field test (P>0.05); (3) NO level of mouse hippocampus tissue was decreased in 0.075% group (P<0.01).


CONCLUSIONS
The findings suggest that decreased hippocampus NO level may contribute to the Pb-induced deficits in learning and memory processes.
Sun
Li
L
The Affiliated Children Hospital of Medical School, Zhejiang University, Hangzhou 310003, Zhejiang, China. hjsl@mail.hz.zj.cn
Zhao
Zheng-Yan
ZY
Hu
Jian
J
Zhou
Xie-Lai
XL
D000818:Animals; D004305:Dose-Response Relationship, Drug; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism*; D008568:Memory / Q000187:drug effects* / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D009569:Nitric Oxide / Q000378:metabolism*; D009942:Organometallic Compounds / Q000633:toxicity*; D015431:Weight Loss
D009942:Organometallic Compounds; D009569:Nitric Oxide; C008261:lead acetate