慢性强迫游泳应激抑郁模型大鼠行为学及海马Ca^(2+)/钙调蛋白依赖性激酶Ⅱ的变化

Changes of behavior,Ca^(2+)/CaMKⅡ in hippocampus of rats with chronic forced swimming stress model

目的探讨慢性强迫游泳应激(CFSS)模型大鼠行为学的改变和海马神经元Ca2+/钙调蛋白依赖性激酶Ⅱ(CaMKⅡ)的表达变化。方法成年健康雄性Wistar大鼠60只,随机分为对照组(30只)和慢性强迫游泳应激组(30只)。慢性强迫游泳组强迫游泳4周,制备慢性强迫游泳应激模型;糖水偏好实验、开场实验和Morris水迷宫检测大鼠行为学改变;荧光探针标记法测定海马神经元内Ca2+浓度;胶体金免疫电镜、免疫印迹和RT-PCR检测CaMKⅡ的表达变化。结果慢性强迫游泳应激组糖水消耗量和糖水偏好百分比分别为4.114±0.644和86.610±4.450,对照组为8.157±1.105和94.930±2.893,差异有统计学意义(P<0.01);开场实验中慢性强迫游泳应激组和对照组的直立次数分别为1.75±0.96和6.00±0.82,差异有统计学意义(P<0.05);水迷宫实验逃避潜伏期分别为(20.762±3.236)s和(5.632±1.065)s,差异有统计学意义(P<0.01);海马神经元内游离Ca2+浓度分别为(498.94±40.45)nmol/L和(288.91±32.42)nmol/L,差异有统计学意义(P<0.01);CaMKⅡ蛋白和mRNA相对表达水平均高于对照组(P<0.01)。结论海马Ca2+及CaMKⅡ的表达上调,可能是抑郁模型大鼠情感行为异常的病理生理基础之一。

Objective To observe the changes of behavior, intracellular free calcium and the expression of calmodulin dependent protein kinase Ⅱ （CaMK Ⅱ ） in the hippocampal neurons of chronic forced swimming stress rats. Methods Male Wistar rats were randomly divided into control group and chronic forced swimming stress group. The behavior was examined using sucrose preference test, open-filed test and Morris water maze. The intracellular free calcium was examined by fluorescence spectrophotometer. The expression of CaMK Ⅱ was detected using colloidal gold immunoelectron microscopy technique, Western blotting and RT-PCR. Results The consumption of sucrose and erect quantity of chronic forced swimming stress group were lower than those of control group（ P 〈 0.01, P 〈 0.05）. The escape latency time in Morries water maze test of chronic forced swimming stress group was higher than that of control group（ P 〈 0.01 ）. The intracetlular free calcium level and the expression of CaMK Ⅱ in the hippocampus was higher than that of control group（ P 〈 0.0l ）. Conclusion The lasting dysfunction of Ca2＋/CaMK Ⅱ signaling cascades in hippocampus may play important roles in the pathogenesis of chronic forced swimming stress rats.