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《中国神经再生研究：英文版》
>Short-term versus long-term water maze training effects on hippocampal neuronal synaptic plasticity in a rat model of senile dementia
Short-term versus long-term water maze training effects on hippocampal neuronal synaptic plasticity in a rat model of senile dementia
BACKGROUND:Changes in synaptic plasticity might underlie senile dementia,and might be the neurobiological basis for learning and memory dysfunctions in patients with Alzheimer's Disease.OBJECTIVE:To investigate the effects of water maze training on hippocampal neuronal synaptic plasticity in rats with senile dementia,and to compare changes in synaptic plasticity between short-and long-term water maze training sessions.DESIGN,TIME AND SETTING:A randomized,controlled,neuromorphological observation with animal models of senile dementia was performed at the laboratory of College of Pharmacy,Chongqing Medical University between November 2006 and April 2007.MATERIALS:Fifty male,Sprague Dawley rats were randomized into five groups,with 10 rats per group:model,control,sham-operated,short-term water maze training,and long-term water maze training.METHODS:In the model group,senile dementia was induced by fimbria-fornix lesion method.The control rats remained untreated.In the sham-operated group,water maze training was performed without fimbria-fornix lesion induction.Rats from the short-term water maze training group underwent 20-day water maze training from day 26 after fimbria-fornix lesion induction.The long-term water maze training group underwent 40-day water maze training beginning at day 6 following fimbria-fornix lesion induction.Beginning at day 41,each group underwent 5-day spatial learning and memory training.MAIN OUTCOME MEASURES:Following experimentation,the morphological parameters of synapses,including synaptic numerical density,synaptic surface density,and the average synapse size were stereologically measured.Through the use of an electron microscope,synaptic morphological changes in the hippocampal CA3 region were observed.RESULTS:Compared with the control group,synaptic numerical and surface densities were significantly decreased in the model group(P < 0.01).Synaptic numerical and surface densities significantly increased in the short-and long-term water maze training groups,compared with the model group(P < 0.01),and these values were also significantly greater in the long-term water maze training group than in the short-term water maze training group.The model group exhibited larger average sizes of synaptic conjunctions,compared with the control group(P < 0.01).Synaptic conjunction size was significantly less in the short-and long-term water maze training groups than in the model group(P < 0.01),and the long-term water maze training group exhibited smaller synaptic conjunction sizes compared with the short-term water maze training group(P < 0.05).Synaptic morphological changes in the hippocampal neurons were in accordance with stereological measurements.CONCLUSION:Water maze training increased synaptic numerical and surface densities in the hippocampal CA3 region,resulting in numerical and functional changes in synaptic plasticity in rats with senile dementia.Long-term water maze training resulted in better therapeutic effects than short-term water mate training.
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