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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 To investigate the effect of marginal vitamin A deficiency (MVAD) in embryonic stage on learning and memory of juvenile rats and the effect of juvenile intervention. Methods The experiment was divided into normal control group, marginal vitamin A deficiency group (MVAD group) and vitamin A intervention group (VAI group). In the normal control group (10 young rats), the rats and young rats were fed with adequate dietary supplements. The MVAD group (19 young rats) and the young rats were given marginal vitamin A deficiency diet. The VAI group (9 rats) Maternal mice were given marginal vitamin A deficient diet, and young rats were given VA adequate diet 4 weeks after birth. The rats in each group were allowed to grow up to 7 weeks of age. The learning and memory functions of the rats were tested by spontaneous avoidance reaction in the shuttle box. The hippocampal long-term potentiation (LTP) was detected in vitro. The intracellular calcium Changes in concentration. Results: (1) The number of times that the shuttle box actively evacuated the response test to the standard of training was more than that of the normal control group (28.1 ± 4.4) and the MVAD group (17.1 ± 4.4) (P <0.01) ), MVAD group had more training times than VAI group (P <0.05). (2) The percentage of increase in slope of field excitatory postsynaptic potential (fEPSP) induced by LTP in hippocampal slices: (22.9 ± 9.4)% in MVAD group The VAI group (29.5 ± 13.7%) was less than the normal control group (57.5 ± 27.3)% (P <0.01), and there was no significant difference between the VAI group and the MVAD group. (3) The confocal laser scanning confocal microscope Fluorescence intensity was lower in MVAD group (65.1 ± 17.0) and VAI group (85.8 ± 17.1) than that in normal control group (113.6 ± 20.5) (P <0.01), MVAD group was lower than VAI group (P <0.05). Conclusion MVAD can induce learning and memory deficits and impaired hippocampal LTP in young rats. After 4 weeks of life, VA is involved in the learning and memory function. Partial recovery of learning and memory functions may be achieved. VA may affect LTP by regulating calcium influx.