The Effect Of Enriched Environment On Memory And Synaptic Plasticity On Alzheimer’s Mice

Objective:This experiment try to investigate the effect of enriched environment on the ability of learning and memory in Alzheimer’s mice, and to explore it’s possible mechanism,which can provide the theoretical basis for the enriched environment as a mean of intervention in clinical application for AD.Methods:40healthy kunming mice was divided into four groups,such as:normal group of the standard environment, model group of the standard environment, model group of the enriched environment and normal group of the rich environment.There were10mices in every group. Injecting mice intracerebroventricular of condensed matter of Aβ1-40to establish Alzheimer model in mice,the mice of control group were given physiological saline of same volume in the same injection points. Morris water maze was used to test the ability of learning and memory of the experimental mice, transmission electron microscope was used to observate the change of synapses’s ultrastructural in hippocampal CA1,and detecting synaptophysin in hippocampus through the immunohistochemical form.Results:1. The results of Morris water maze experiment:The escape latency of the mice in model group of the enriched environment was significantly shorter than the model group of standard environment (P<0.05); number of model group of the enriched environment across the platform significantly more than the model group of standard environment, the difference was significant (P<0.01).2. The results of detecting synaptic plasticity:Compared with the model group of standard environment,in the control group of the standard environment synaptic numerical density and the surface density was significantly larger(P<0.01), and the average area was lesser(P<0.01). Compared with the model group of standard environment, in the model group of enriched environment synaptic numerical density and the surface density was significantly larger(P<0.01), and the average area was lesser(P<0.01).3. Immunohistochemical staining synaptophysin expression in hippocampus of the results: the expression of synaptophysin was the most in control group of standard environment and control group of enriched environment, the model group of enriched environment was the second, the model group of standard environment was the least.Quantitative analysis showed:compared with the control group of standard environmental, the average optical density of synaptophysin was significantly lower in the model group of standard environment (P<0.01). Compared with the model group of standard environmental, the average optical density of synaptophysin was significantly higher in the model group of enriched environmental(P<0.01).Conclusion:1. The enriched environment significantly enhanced ability of learning and memory in Alzheimer’s mice.2. The enriched environment reduced the damage to the synapses of Alzheimer’s mice, and promoted the formation of new synapses and synaptic connections.The enriched environment enhanced ability of learning and memory in Alzheimer’s mice,which may be related to synaptic plasticity.3. The enriched environment increased the expression of synaptophysin in hippocampus, prompted the reconstruction of the synapses, thereby improved ability of learning and memory in Alzheimer’s mice.