脑发育不同阶段慢性铅暴露对大鼠在体海马不同时间一氧化氮含量及合酶活性的影响

Effect of chronic lead exposure at brain different developmental stages and different time on NO and NOS in rat hippocampus in vivo

目的:比较脑发育不同阶段低浓度慢性铅暴露对大鼠在体海马一氧化氮含量及合酶活性的差异。方法:分别在仔鼠出生21天、42天、63天时测定对照组、断乳后暴露组、母体暴露组和持续暴露组仔鼠血铅含量和海马NO含量和NOS活性,并与对照组进行比较。结果:各暴露组在不同时间血铅含量均高于对照组(P<0.05)。断乳后铅暴露组和持续铅暴露组NOS活性与对照组相比均有显著性差异(P<0.05),出生21天时明显高于对照组,而42天和63天明显低于对照组。持续暴露组NO含量与对照组相比有明显差异,出生21天时明显高于对照组,而42天和63天明显低于对照组。结论:脑发育任一阶段的慢性铅暴露均对海马NO含量和NOS活性有影响。与发育成熟海马相比,未成熟期海马对铅的神经毒性更为敏感,突触可塑性更易受损。

Objective： To investigate the effects of chronic lead exposure at brain different developmental stages on NO and NOS in rat hippocampi in vivo. Methods：Concentration of lead in blood , concentration of NO and activity of NOS in rat hippocampus were detected at the 21,42 or 63 days after the young rat were born. Results：The concentration of lead in blood was significantly differences at different times between the control and the three Pb-exposed groups. The activity of NOS and concentration of NO in rat hippocampus between lead-expoesd depart from latex group, lead-expoesd continously group and control group were significantly difference. Conclusion： Chronic lead exposure during brain any developmental stage may have effect on the concentration of NO and the activitr of NOS in rat hippocampi. The immature hippocampus might be higher vulnerable as compared with the mature one to lead neurotoxicity.