行为训练对胎儿生长受限子鼠学习记忆能力及海马NR2B、GluR1表达的影响

Effect of behavioral training on learning and memory capacity and changes of hippocampal NR2B and GluR1 expressions in FGR offspring rats

目的探讨行为训练对胎儿生长受限(FGR)子鼠学习记忆能力及海马谷氨酸受体NR2B和GluR1表达的影响。方法被动吸烟法建立大鼠FGR模型,将子鼠分为FGR组及正常组,两组再各自随机分为训练组和非训练组,于生后2、4月行Morris水迷宫行为训练,应用避暗实验和跳台实验检测学习记忆能力,采用免疫组织化学法观察海马脑区谷氨酸受体NR2B及GluR1的表达情况。结果学习记忆成绩比较,FGR组差于正常组,训练组优于非训练组;FGR训练组学习成绩提高明显,模型因素及训练因素有交互效应(P<0.05);NR2B、GluR1在海马CA1区、CA3区的表达比较,FGR组低于正常组;训练组CA1区GluR1、NR2B的表达量明显高于非训练组;2月龄CA1区GluR1的表达,模型因素及训练因素有交互效应(P<0.05)。结论行为训练可提高FGR子鼠学习记忆能力,可能与海马CA1区谷氨酸受体NR2B、GluR1的表达上调有关。

Objective To study the effect of behavioral training on the learning and memory abilities and changes of NR2B and GluR1 expressions in the hippocampus of offspring rats with fetal growth retardation （FGR）.Methods A FGR model was established in SD rats by passive smoking.The offspring rats were divided into FGR group and control group,each then randomized into training and untrained group.Morris water maze behavioral training was carried out in postnatal months 2 and 4,and the learning and memory abilities of the young rats were assessed using dark-avoidance test and step-down test.NR2B and GluR1 expression in the hippocampus of the rats were detected by immunohistochemistry.Results In the dark-avoidance and step-down tests,the FGR rats showed deteriorated learning and memory performance in comparison with the control group,but behavioral training resulted in improved performance of the rats.The performance in FGR group was much improved after behavioral training,and the model factor and the training factor showed a significant interaction （P0.05）.The expression of NR2B and GluR1 in CA1 and CA3 regions of the hippocampus decreased in FGR group,then the their expressions in the CA1 region increased after training in both FGR and control groups,and the increment was especially obvious in GluR1 expression in the CA1 region at postnatal month 2.The two factors showed a significant interaction （P0.05）.Conclusion Behavioral training can improve the learning and memory abilities of FGR offspring rats,the mechanism of which is probably related to increased expression of NR2B and GluR1 in the CA1 region of the hippocampus.