Effects Of Exercrise On The Neurons In The Hippocampus Of Early APP/PS1 Transgenic Mouse

Part OneObjective:To investigate the early changes of the the neurons in the hippocampus CA1 subfield, in the hippocampus CA3 subfield and in the dentate gyrus (DG) in the transgenic mouse model of Alzheimer’s disease with the stereological methods.Methods:Ten 10-month-old male APP/PS1 transgenic mouse and Ten 10 month-old male littermate wild-type mouse were used. Morris water maze was used to test the spatial learning and memory ability for seven consecutive days. From day 1 to day 6, the time latency was recorded for the spatial cognition capability. On the 7 day, the target zone frequency and the percentage of time in target quadrant zone were recorded for learning memory capability. After the Morris water maze,6 mouse were randomly sampled from each group, and the stereological methods were used to investigate the volumes of each subfield of the hippocampus and the entire hippocampus, and the number of the neurons in the CA1, CA3 subfield and DG.Results:We found that when compared to wild-type group, the escape latency of APP/PS1 group was significantly increased, the number of cross platform and the time percentage of platform quadrant were not significantly different, and the volume of the hippocampus and the volumes of the CAl, CA3 subfield and DG of the hippocampus were significantly different by 16.1%,17.1%,14.5%,27.8%, repectirely(p< 0.01, p< 0.05,p< 0-05, p< 0.01), and the the number of neurons in CA1 subfield, CA3 subfield and DG of APP/PS1 group were significantly reduced by 33.3%,34.3%,58.39%, repectirely (p< 0.05, p< 0.05, p< 0.01).Conclusions:1.10-month-old transgenic AD mouse had started to appear behavioral changes.2. The hippocampus volume and the the number of neurons in CA1 subfield, the CA3 subfield and DG in the 10-month-old transgenic AD mice were significantly reduced when compared to the wild-type group, which might be one of the morphological bases for the behavioral deficits of the 10-month-old transgenic mouse model of AD.Part TwoObjective:To investigate the effects of the exercise on the number of the neurons in the hippocampus CA1 subfield, in the hippocampus CA3 subfield and in the dentate gyrus (DG) of early transgenic AD mouse with the stereological methods.Methods:Twenty 6-month-old male APP/PS1 transgenic mouse were randomly divided into running group and control group(10 mouse per groop). The running group mice ran for four months, the control group mouse was housed in standared condition without running. Then, the behaviors of the mice from both groups were assessed with the Morris water maze test, and the volume of the hippocampus and the volumes of the hippocampal CA1, CA3 subfield and DG and the mumber of the neurons in the CA1, CA3 subfield and DG were investigated with the stereological methods.Results:We found that when compared to control group, the escape latency of running group was significantly shortened, the time percentage of platform quadrant and the number of cross platform were significantly increased, the volume of the hippocampus and the volume of the CA1, CA3 subfield and DG were significantly increased by 13.3%,42.8%, 37%,27.3%, repectively (p< 0.05,p< 0.01,p< 0.01,p< 0.05), and the the number of neurons in CA1, CA3 subfield and DG of running group were significantly increased by 61.8%,40.5%,62.2%, repectively(p< 0.01, p< 0.01, p< 0.05).Conclusions:1. The present results suggested that exercise could delay the decline in the learning and spatial memory ability of early AD mouse.2. Exercise could delay the progress of the hippocampcal atrophy. 3. Exercise could delay the progress of the neuron death in the CA1, CA3 and DG of early transgenic AD mouse.