长期接触氯化甲基汞对大鼠不同发育阶段仔鼠海马NMDA受体2A亚单位表达的影响

Effects of chronic exposing to methylmercury chloride on NMDAR-2A subunit expression in hippocampus of newborn rats during developmental stages

目的 :探讨氯化甲基汞 (MMC)对不同发育阶段大鼠幼仔海马组织 N-甲基 - D-天冬氨酸 (NMDA)受体 2 A亚基 (NR2 A)表达的影响。方法 :体重为 (1 2 0± 2 0 ) g雌性大鼠随机分为对照组和实验组 ,连续 90 d每天分别进食含不同剂量 MMC (0 .75、 1 .5 0和 3.0 m g· kg- 1 )的饲料后 ,取其生后 7、 1 4、 2 1和 2 8d的仔鼠海马组织提取 NR2 A蛋白 ,采用 Western blotting法观察 MMC对不同发育阶段大鼠幼仔海马组织 NR2 A表达的影响。结果 :对照组和实验组各发育阶段仔鼠海马组织都有 NR2 A的表达 ,生后 1 4 d达到高峰。实验组大鼠幼仔在生后7、 1 4、 2 1和 2 8d海马组织 NR2 A表达与对照组相比均有不同程度的减少。结论 :NMDA受体参与中枢神经系统发育的调节 ;甲基汞所致发育阶段脑损伤可能与其引起

Objective To study the effects of methylmercury chloride (MMC) on NMDA receptor (NMDAR) 2A subunit (NR2A) in hippocampus of newborn rats chronically exposed to MMC during developmental stages. Methods Female Wistar rats (120±20 g) were randomly divided into control group and experimental group. In experimental group,the rats were fed on forage containing different dosage of MMC (0 75,1 50 and 3 00 mg·kg -1 ) each day for 90 days. NR2A proteins were exacted from hippocampus of newborn rats on P (postnatal days) 7,P14,P21, and P28. NR2A protein expression was investigated with Western blotting. Results NR2A protein was detected in both control and experimental groups. Expression of the NR2A reached the peak at P14. A decreasing tendency appeared in amount of NR2A from hippocampus of MMC exposed rats on P7, 14, 21, and 28 compared with control group. Conclusion NMDAR in rat brain involves in brain developmental process. Decrease of NR2A expression in rat exposed to MMC may be the key molecular mechanism of MMC damage of the developing brains.