不同训练方式建立大鼠空间记忆后海马结构中BDNF表达的变化

摘要

目的：研究短期强化训练能否建立可靠的空间长时记忆；用不同训练方式建立空间记忆后，大鼠海马结构中脑源性神经营养因子（BDNF）的表达是否会发生变化。方法利用Morris水迷宫建立大鼠空间短期记忆、长期记忆和短期强化训练形成的长期记忆3种模型，用激光共聚焦显微镜观察正常（NC）组、短期记忆（ST）组、长期记忆组（LT）和短期强化训练形成的长期记忆（SRT ）组大鼠海马各亚区的BDNF的分布情况。结果 Morris水迷宫定位航行实验中LT组和SRT组间寻找站台平均潜伏期和策略差异均无统计学意义；记忆检测发现，LT组大鼠除了在站台所在象限的停留时间明显长于SRT组，差异有统计学意义（P＜0.05）外，两组大鼠寻找站台潜伏期和策略以及穿越站台次数差异均无统计学意义。LT组与NC组及ST组比较，海马齿状回和CA1区的BDNF免疫荧光反应明显增强，差异有统计学意义（均 P＜0.05）；SRT组与NC组以及ST组比较，海马齿状回和CA1区的BDNF免疫荧光反应明显增强，差异有统计学意义（P＜0.05或 P＜0.01）。LT组与SRT组之间，NC组与ST 组之间，海马各区的BDNF表达差异均无统计学意义。结论短期强化训练可建立与长期训练基本相同的长期记忆。BDN F与空间长期记忆的形成密切相关，其可能不参与空间短期记忆的形成或调节。%Objective To investigate whether short reinforcing training can establish stable spatial long‐term memory and how the brain‐derived neurotrophic factor (BDNF) expression in the hippocampus changes after the establishment of spatial memory with different trainings. Methods Long‐term memory was established by spatial short‐term memory training (ST group) ,spatial long‐term memory training (LT group)or short reinforcing training (SRT group)in Morris water maze.Laser scanning confocal microscopy was used to observe the distribution of BDNF in each area of the hippocampus in normal control group(NC) ,ST ,LT and SRT groups.Results Morris water maze testing showed that there was no significant difference in the mean latency and the target‐seeking strategies between the LT and SRT groups. The examination of the memories following dif‐ferent trainings indicated that the mean latency and the target‐seeking strategies as well as the times of crossing the target in LT group were not significantly different from those in SRT group ,except that the mean time remaining in the platform quadrant in LT group was significantly longer than that in SRT group(P<0.05).The integral absorbance(A)value of BDNF in the dentate gyrus (DG) and CA1 area of the hippocampus was significantly increased in LT and SRT groups compared with that in NC and ST groups(P<0.05 or P<0.01).In addition ,no significant difference in the integral A value of BDNF in CA1 ,CA3 and DG of the hippocampus was observed between NC and ST groups or between LT and SRT groups.Conclusion The short reinforcing training can establish long‐term spatial memory ,which is almost the same as that established by the long‐term training.BDNF is closely associated with spatial long‐term memory formation and it may not be involved in the formation or regulation of spatial short‐term memory.