边缘型维生素A缺乏对幼鼠学习记忆的影响及干预效果  

Effects of marginal vitamin A deficiency and intervention on learning and memory in young rats

作　　者：春婷[1] 李廷玉[1] 刘友学[1] 瞿平[1] 

机构地区：[1]重庆医科大学附属儿童医院儿保科,400014

出　　处：《中华儿科杂志》2005年第7期526-530,共5页Chinese Journal of Pediatrics

基　　金：国家自然科学基金资助项目(30471462)

摘　　要：目的了解胚胎期开始的边缘型维生素A缺乏(MVAD)对幼鼠学习记忆的损害及幼年期干预的效果。方法实验分为正常对照组、边缘型维生素A缺乏组(MVAD组)、维生素A干预组(VAI组)。正常对照组(幼鼠10只)母鼠和幼鼠均给予VA充足饲料;MVAD组(幼鼠19只)母鼠和幼鼠均给予边缘型维生素A缺乏饲料;VAI组(幼鼠9只)母鼠给予边缘型维生素A缺乏饲料,幼鼠于生后4周开始给予VA充足饲料。待各组幼鼠长至7周龄,用穿梭箱主动回避反应实验测试学习记忆功能,离体脑片检测海马长时程增强(LTP),激光共聚焦检测脑片强直刺激后细胞内钙离子浓度的变化。结果(1)穿梭箱主动回避反应实验达到学会标准的训练次数:VAI组(28.8±4.1)次和MVAD组(45.6±12.1)次分别多于正常对照组(17.1±4.4)次(P<0.01),MVAD组的训练次数多于VAI组(P<0.05);(2)海马脑片诱发LTP的场兴奋性突触后电位(fEPSP)斜率增加的百分比:MVAD组(22.9±9.4)%和VAI组(29.5±13.7)%小于正常对照组(57.5±27.3)%(P<0.01),VAI组与MVAD组差异无统计学意义;(3)激光共聚焦检测脑片强直刺激后细胞内相对荧光强度:MVAD组(65.1±17.0)和VAI组(85.8±17.1)低于正常对照组(113.6±20.5)(P<0.01),MVAD组低于VAI组(P<0.05)。结论胎儿期开始的MVAD可导致幼鼠学习记忆功能和海马LTP受损,生后4周给予VA干预,其学习记忆功能有部分恢复;VA可以通过调节细胞钙离子内流而影响LTP。Objective Previous studies have demonstrated that vitamin A and its active derivatives function as essential competence factors for long-term synaptic plasticity within the adult brain. But little is known if marginal vitamin A deficiency (MVAD) beginning from embryonic period affects the brain development and the ability of learning and memory in young rats. The aim of this study was to identify the effects of MVAD and vitamin A intervention (VAI) on learning, memory and the hippocampal CA1 long-term potentiation (LTP) in young rats. Methods Rats were divided into control, MVAD and VAI groups in this study. In control group (10 young rats) the dams and pups were fed with normal diet (VA 6500 IU/kg). In MVAD group (19 young rats) the dams and pups were fed with MVAD diet (VA 400 IU/kg). In VAI group (9 young rats) the dams were fed with MVAD diet and the pups were fed with normal diet from postnatal week 4. All the young rats were killed at the age of 7 weeks. During the last week of the experiment, the shuttle box active avoidance reaction tests were carried out. At week 7, the hippocampal CA1 LTP was detected by electrophysiological technique and relative intensity of fluorescence in cells in hippocampal slices was measured by confocal laser scanning microscopy labeled by fluo-3. Results (1) The times to reach the learning standard in both VAI group (28.8±4.1) and MVAD group (45.6±12.1) were more than control group (17.1±4.4) (P<0.01), and that of MVAD group was more than VAI group (P<0.05) in active avoidance reaction tests. (2) The changes of field excitatory postsynaptic potentials (fEPSP) slope for MVAD group (22.9%±9.4%) and VAI group (29.5%±13.7%) were less than that of control group (57.5%±27.3%), respectively (P<0.01). No significant difference was found between VAI and MVAD groups (P>0.05). (3) No significant differences of relative intensity of fluorescence in cells were found among the three groups before the tetanus stimulation. However, the significantly low relative intensity of fluorescence

关 键 词：维生素A缺乏 边缘型 幼鼠 干预效果 学习记忆功能 正常对照组 细胞内钙离子浓度 兴奋性突触后电位 主动回避反应 海马长时程增强 激光共聚焦 相对荧光强度 强直刺激 VAI 海马LTP 钙离子内流 实验测试 离体脑片 海马脑片 

分 类 号：R723[医药卫生—儿科]