长期饮用纯净水加重铅对大鼠海马NMDA受体以及空间学习记忆能力的抑制

目的 比较长期饮用纯净水和自来水对血脑铅蓄积以及铅神经毒性的差异.方法 断乳雄性SD大鼠104只,计算机编程完全随机化实验设计分为4对8组,饮水分别为自来水、纯净水、自来水含铅(醋酸铅)50 mg/L、纯净水含铅50 mg/L、自来水含铅200 mg/L、纯净水含铅200mg/L、自来水含铅800 mg/L、纯净水含铅800 mg/L.各组食物及其他处理因素完全一致.分别在12、24周时对大鼠进行Morris水迷宫实验中的定向航行、空间探索和可视平台实验.28周时处死大鼠取材,采用原子吸收分光一石墨炉法测定血铅和脑铅,采用RT-PCR法检测海马NMDA受体NR1、NR2A和NR2B亚基mRNA的表达.结果 铅染毒剂量相同时,不同的饮水对大鼠血铅的影响未显示差异,但饮用纯净水的大鼠脑铅均高于饮用自来水的大鼠,其中对照组及高铅组的增高差异具有统计学意义;饮用纯净水的大鼠其NR1、NR2A、NR2B亚基mRNA的表达均低于饮用自来水的大鼠,其中低铅组的NR2A亚基表达差异具有统计学意义;24周水迷宫实验中,饮用纯净水的大鼠其定向航行实验的逃逸潜伏期长于自来水组,其中低、中铅剂量组差异都具有统计学意义,且差异来自于实验的前2 d.结论 与饮用自来水相比较,长期饮用纯净水可增加大鼠脑组织铅蓄积,降低NMDA受体NR1,NR2A,NR2B亚基mRNA的表达,同时迟滞其空间学习记忆能力.低剂量铅暴露下上述效应更为明显.

Long-term drinking purified water my aggravate the inhibition of NMDA expression and spatial learning ability induced by lead on rat

Objective To compare brain lead acctunulation and neurotoxicity induced by had under drinking purified water and tap water Oil rat.Methods AU 1 04 male weaning SD rats were randomly divided into eight groups,matched-four pairs according to drinking water:tap water,purified water,tap water with lead 50 mg/L(1ead acetate water-solution).purified water with lead 50 mg/L,tap water with lead 200 ms/L.purified water with lead 200 mg/L.tap water with lead 800 mg/L All were fed witlI normal food and endronmental cognitions kept consistent.Morris water maze(including Place Navigation,Spatial Probe Test, Visible Platform Trial)was measured to test rat spatial learning at the 12 and 24 week.At the end of the experiment(28 week),rats were killed and the lead of brain and blood was measured by Graphite furnace atomic absorption spectrometric method;the NRl,NR2A,NR2B 0f NMDAR(N.methyl.D.aspartame receptor)in hippocampus were analyzed by RT-PCR Results Under the sanle lead exposure.nO significant differences were observed in blood lead.however.brain lead level showed hisher in drinking purified water group than that in tap water group.Expression of NRl.NR2A and NR2B in hippocampus of the rats drinking purified water WaS lower than those drinking tap water,especially at low lead exposure(50 ms/L)(P