早期应激减低C57小鼠认知功能相关的海马神经元树突棘密度

Early-life stress reduces the dendritic spine density of the memory-associated hippocampus neurons in C57 mice

目的:借助高尔基染色法探讨早期应激对海马CA1、CA3区锥体细胞区神经元树突棘密度的影响。方法:自出生后第2~9天,持续改变新生C57小鼠的生存环境1周,建立早年生活应激动物模型。采用ELISA CORT试剂盒检测第9日龄C57小鼠血浆皮质酮含量;针对120日龄小鼠行物体识别实验、物体位置识别实验,检测小鼠的认知功能;运用Golgi染色定量分析第9、21、120日龄3个时间点海马CA1、CA3区锥体细胞神经元树突棘的密度。结果:9日龄应激组小鼠皮质酮含量显著增高(应激组为10.617 ng/ml±2.012 ng/ml,对照组为3.300 ng/ml±0.122 ng/ml);120日龄应激组C 57雄性小鼠对新旧物体的识别能力表现为长期记忆(24 h)能力减低;早期应激所致的负性效应持续损害海马锥体细胞区神经元至成年,表现为120日龄组C 57雄性小鼠神经元树突棘密度(每20μm树突节段树突棘数量)降低。结论:早期应激所致负性效应延缓了海马锥体细胞区神经元树突棘的成熟和稳定,导致机体认知功能发育迟缓。

Objective:To study the impact of early-life stress on the development of spiny neurons in the hippocampus by Golgi staining.Methods:The early-life stress animal model was created by changing the growth environment of new born C57 pups from P2-P9.The Golgi staining,object recognition test,and object location test were employed to investigate the effect of stress on the spines of hippocampus neurons.Results:The high-level corticosterone was found in P9 ES pups(stress group 10.617 ng/ml±2.012 ng/ml;control 3.300 ng/ml±0.122 ng/ml).The discrimination index(DI)of object recognition test and object location test showed that P120 stress group male mice was significantly lower than the control mice in long-term memory test(24 h).The number of mature spines was reduced in stress group male mice.Conclusion:Early-life stress interrupts the dendritic differentiation and postpones the maturation of spines of neurons in the hippocampus pyramidal cell area.