Zhang J, Lü J, Cui T, Xie G
Institute of Occupational Medicine, Chinese Academy of Preventive Medicine, Beijing 100050, China.
Wei Sheng Yan Jiu. 2001 Jan;30(1):4-6.
Chronic lead exposure during brain development is known to affect cognitive and behavioral functions in children and animals. The lead exposure on pregnant rats was used as a model to examine the effects of lead on the long-term potentiation(LTP) in hippocampal dentate gyrus(DG) region in vivo and the expression of NMDAR-2A mRNA by in situ hybridization in the off-springs. Female rats were exposed to 0.5 g/L or 2 g/L lead acetate in drinking water since 10 days before mating to weaning. The filial rats of 70-90 days old with blood lead levels below 100 micrograms/L were prepared for recording their DG-evoked population spike(PS) in the hippocampal DG area in vivo. The results showed that the range of LTP were (136 +/- 31)% in low lead group, (145 +/- 30)% in high lead group, and (319 +/- 114)% in control group. The reduction of NMDAR-2A mRNA expression 34%-44% in the granule and pyramidal cell layers caused by lead were seen in 21 days old rats. It indicated that the cognitive deficits induced by low-level lead exposure in early stage of life may persist to adulthood, and the modified NMDAR gene expression may play a key role in the cognitive deficits associated with lead exposure during development.
已知在大脑发育过程中慢性铅暴露会影响儿童和动物的认知及行为功能。以妊娠大鼠铅暴露为模型，在体研究铅对后代海马齿状回（DG）区长期增强效应（LTP）的影响，并用原位杂交法检测NMDAR - 2A mRNA的表达。从交配前10天至断奶，雌性大鼠饮用含0.5 g/L或2 g/L醋酸铅的水。选取血铅水平低于100微克/升的70 - 90日龄子代大鼠，在体记录其海马DG区诱发的群体峰电位（PS）。结果显示，低铅组LTP幅度为（136±31）%，高铅组为（145±30）%，对照组为（319±114）%。在21日龄大鼠中可见，铅导致颗粒细胞层和锥体细胞层中NMDAR - 2A mRNA表达降低34% - 44%。这表明生命早期低水平铅暴露所致的认知缺陷可能持续至成年期，且NMDAR基因表达改变可能在发育期间铅暴露相关的认知缺陷中起关键作用。
