2015•Zhonghua xingwei yixue yu naokexue zazhiRequires access
Effects of enriched environment on synaptic plasticity in hippocampal CA1 region in senescence accelerated mouse
Jianzhong Li, Xinghua Hao, Huixian Cui, Xuemin Liu, Zhibing Wu, Ming Li, Haiping Wu
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Abstract
Objective
To explore the effects of enriched environment on synaptic plasticity in hippocampal CA1 region in senescence accelerated mouse.
Methods
Both twenty-four five-month-old healthy male SAMP8 and twenty-four five-month-old healthy male SAMR1 were randomly divided into enriched environment(EE) group and standard environment(SE) group(12 mice in each group). Mice in the 2 groups were subjected to the two different environments for 60 days. The apical dendritic thorns density in hippocampal CA1 region was measured by Golgi staining. The expression of synaptophysin in hippocampal CA1 was determined by immunohistochemical staining and image analysis system. The synaptic number density(Nv)and surface density(Sv) in hippocampal CA1 region were observed and analyzed by transmission electron microscope, stereology and image analysis system.
Results
For SAMP8 in EE group, the density of dendritic spines in hippocampal CA1 region was (1.223±0.062)/μm, the average absorbance of synaptophysin was (0.111±0.021) and the parameters of Nv and Sv were (3.742±0.052)/μm3 and (0.151±0.018)μm2/μm3. For SAMP8 in SE group, the density of dendritic spines in hippocampal CA1 region was (1.142±0.070)/μm, the average absorbance of synaptophysin was (0.091±0.022) and the parameters of Nv and Sv were (3.626±0.049)/μm3 and (0.124±0.018)μm2/μm3. For all indicators, there was a significant difference between two groups (P<0.01). There was statistically significant difference in all indicators between SAMR1 in EE group and SAMR1 in SE group(P<0.05).
Conclusion
Enriched environment can adjust synaptic plasticity in hippocampal CA1 neurons, significantly increase the density of dendritic spines, the expression of synaptophysin, synaptic number density and surface density, which may be the mechanism of enriched environment improving the learning and memory ability in mice with dementia.
Key words:
Enriched environment; Hippocampal CA1 region; Dendritic spine; Synaptic plasticity; Synaptophysin