ABSTRACT
Objective To investigate the effects of intervention with the fluoxetine and the enriched environment on chronic stress induced depression behavior of rats,and the changes of myelin basic protein in hippocampus and prefrontal regions.Methods 50 adult male SD rats were randomly divided into control group,fluoxetine group,model group,enriched environment (EE) group and EE plus fluoxetine group.Fluoxetine group,model group,EE group and EE plus fluoxetine group underwent chronic unpredictable stress stimulus in the first to third week,and fluoxetine group,EE group,EE plus fluoxetine group underwent the intervention with EE and (or) fluoxetine in the fourth to sixth week.The changes of behavior in rats were evaluated by sucrose water consumption,open field test and weight changes.The content of MBP in each subregion of hippocampus and prefrontal regions of rats was measured with immunocytochemical methods.Results At the third weekend,the assessed behaviors of stressed rats decreased significantly compared with control group (P＜0.05);and at the sixth weekend,the behaviors of stressed rats restored after treated with EE and (or) fluoxetine.The content of MBP in the rat hippocampus CA1,DG area and prefrontal area of model group declined clearly compared with control group (mean density of model group orderly:0.199±0.024,0.204±0.021,0.225±0.028;control group orderly:0.279±0.034,0.288±0.043,0.308±0.053,P＜0.05).The content of MBP in the rat of fluoxetine group,EE group and EE plus fluoxetine group increased obviously compared with model group (fluoxetine group orderly:0.259± 0.047,0.266± 0.052,0.284 ± 0.031;EE group orderly:0.257±0.038,0.258±0.042,0.286±0.037;EE plus fluoxetine group orderly:0.271± 0.046,0.279±0.040,0.289±0.041,P＜0.05).Conclusion The depression-like behavior of rats induced by chronic unpredictable stress is associated with the change of the content of MBP in hippocampal CA1,DG area and prefrontal area;and the depression-like behavior and the content of MBP decrease are reversed after the intervention with fluoxetine and EE.