不同的幼年成长环境对小鼠学习记忆的影响
发布时间：2018-11-05 14:12
【摘要】： 丰富的环境对人和动物的学习记忆能力具有促进作用,并可补偿脑损伤导致的障碍及神经退化,而对中枢神经系统发生影响的生理机制仍不清楚。本研究探讨了丰富和贫乏的环境对幼年昆明小鼠(Mus musculus Km)的空间性学习记忆、情绪性学习记忆的影响及其内在机制。 3周龄幼年昆明小鼠被分为以下3组:对照组,丰富环境组,贫乏环境组。从环境处理第4周开始,每周从各组中随机选取5只动物,每天腹腔注射5-溴尿嘧啶(5-BrdU)(100mg/Kg)1次,连续5天,第6天断头取材进行新生神经元的标记,并用TUNEL法检测各组动物凋亡神经元的数量,连续检测3周,第7周采用水迷宫及电跳台方法对小鼠的空间和情绪性学习与记忆能力进行测试,并测定小鼠的颞皮层及海马匀浆中的MDA(丙二醛)及SOD(超氧化物歧化酶)含量,以此来研究不同环境处理对小鼠行为学改变及机体内氧化应激水平变化之间的关系。 研究结果发现:(1)贫乏环境暴露后,小鼠前期活动力下降,后期攻击力增强,易激怒。而丰富环境暴露的小鼠则比较温顺。(2)水迷宫测试中,与对照组相比,贫乏环境组(impoverished growth environment,IGE)找到平台的潜伏期仅在第3天明显延长;与丰富环境组(enriched growth environment,EGE)相比,第2天、第3天IGE组找到平台的潜伏期均比EGE组明显延长。电跳台测试中,与对照组相比,IGE组第1天跳上平台的潜伏期明显高于后者;对错误次数的统计结果表明,第1天与对照组相比,IGE组的错误次数明显更多,第2天虽然发生错误的次数有所减少,但仍比对照组多;此外,与EGE组相比,IGE组在发生错误的次数上明显高于后者。(3)取10%颞皮层及海马组织匀浆后测得的SOD值与对照组相比,EGE组明显升高,IGE组明显下降;此外,IGE组与EGE组相比SOD值显著下降。在10%颞皮层及海马组织匀浆后测得的MDA值,与对照组相比,EGE组明显下降,IGE组明显升高;此外,IGE组与EGE组相比MDA值显著升高。(4)采用5-BrdU标记法检测海马的CA3区新生神经元,EGE组有较多数量的阳性细胞着色:IGE组则基本没有阳性细胞着色,大多为空泡;对照组则不明显。采用TUNEL法检测凋亡神经元,在海马的CA3区,IGE组有较多数量的阳性细胞着色;EGE组则基本没有;对照组则仅少量或个别阳性细胞着色。 上述结果表明,不同的幼年成长环境对小鼠的空间及情绪性学习记忆能力可发生显著的影响,其机制可能与神经元氧化应激作用和神经元的新生、凋亡有关。
[Abstract]:The rich environment can promote the learning and memory ability of human and animal, and can compensate for the disturbance and nerve degeneration caused by brain injury. However, the physiological mechanism of the effect on the central nervous system is still unclear. The purpose of this study was to investigate the effects of rich and poor environment on spatial learning and memory, emotional learning and memory in young Kunming mice. Three-week old Kunming mice were divided into three groups: control group, rich environment group and poor environment group. From the 4th week of environmental treatment, 5 animals were randomly selected from each group every week. 5 brominouracil (5-BrdU) (100mg/Kg) was injected intraperitoneally once a day for 5 days. The number of apoptotic neurons in each group was detected by TUNEL method, and the ability of spatial and emotional learning and memory in mice was tested by water maze and electric platform method in 7 weeks. The contents of MDA (malondialdehyde) and SOD (superoxide dismutase) in temporal cortex and hippocampal homogenate of mice were measured to study the relationship between the changes of behavior and the level of oxidative stress in mice treated with different environments. The results were as follows: (1) after exposure to poor environment, the activity of mice decreased in Prophase, and increased in later stage. (2) in the water maze test, compared with the control group, the incubation period of the poor environment group (impoverished growth environment,IGE) to find the platform was significantly prolonged on the third day. The latency of finding platform in IGE group was significantly longer than that in EGE group on day 2 and day 3 compared with that in enriched environment group (enriched growth environment,EGE). Compared with the control group, the latency of jumping on the platform in the IGE group was significantly higher than that in the control group on the first day. The results showed that the number of errors in the IGE group was significantly higher than that in the control group on the first day, and the number of errors on the second day was lower, but still more than that in the control group. In addition, the frequency of errors in IGE group was significantly higher than that in EGE group. (3) compared with control group, SOD value of 10% temporal cortex and hippocampal homogenate was significantly increased in EGE group and decreased significantly in IGE group. In addition, the SOD value of IGE group was significantly lower than that of EGE group. Compared with the control group, the MDA values measured after 10% homogenate of temporal cortex and hippocampal tissue were significantly decreased in EGE group and increased in IGE group. In addition, the MDA value of IGE group was significantly higher than that of EGE group. (4) 5-BrdU labeling method was used to detect the new neurons in the CA3 area of hippocampus. In the EGE group, a large number of positive cells were stained. In the IGE group, there were almost no positive cells staining, most of them were vacuoles. The control group was not obvious. TUNEL method was used to detect apoptotic neurons. In the CA3 area of hippocampus, there were a large number of positive cells in IGE group, but no positive cells in EGE group, and only a few or individual positive cells in control group. These results suggest that the spatial and emotional learning and memory abilities of mice can be significantly affected by different juvenile growth environments, and the mechanism may be related to oxidative stress, neuronal regeneration and apoptosis.
【学位授予单位】：华中师范大学
【学位级别】：硕士
【学位授予年份】：2008
【分类号】：R33
本文编号：2312323
[Abstract]:The rich environment can promote the learning and memory ability of human and animal, and can compensate for the disturbance and nerve degeneration caused by brain injury. However, the physiological mechanism of the effect on the central nervous system is still unclear. The purpose of this study was to investigate the effects of rich and poor environment on spatial learning and memory, emotional learning and memory in young Kunming mice. Three-week old Kunming mice were divided into three groups: control group, rich environment group and poor environment group. From the 4th week of environmental treatment, 5 animals were randomly selected from each group every week. 5 brominouracil (5-BrdU) (100mg/Kg) was injected intraperitoneally once a day for 5 days. The number of apoptotic neurons in each group was detected by TUNEL method, and the ability of spatial and emotional learning and memory in mice was tested by water maze and electric platform method in 7 weeks. The contents of MDA (malondialdehyde) and SOD (superoxide dismutase) in temporal cortex and hippocampal homogenate of mice were measured to study the relationship between the changes of behavior and the level of oxidative stress in mice treated with different environments. The results were as follows: (1) after exposure to poor environment, the activity of mice decreased in Prophase, and increased in later stage. (2) in the water maze test, compared with the control group, the incubation period of the poor environment group (impoverished growth environment,IGE) to find the platform was significantly prolonged on the third day. The latency of finding platform in IGE group was significantly longer than that in EGE group on day 2 and day 3 compared with that in enriched environment group (enriched growth environment,EGE). Compared with the control group, the latency of jumping on the platform in the IGE group was significantly higher than that in the control group on the first day. The results showed that the number of errors in the IGE group was significantly higher than that in the control group on the first day, and the number of errors on the second day was lower, but still more than that in the control group. In addition, the frequency of errors in IGE group was significantly higher than that in EGE group. (3) compared with control group, SOD value of 10% temporal cortex and hippocampal homogenate was significantly increased in EGE group and decreased significantly in IGE group. In addition, the SOD value of IGE group was significantly lower than that of EGE group. Compared with the control group, the MDA values measured after 10% homogenate of temporal cortex and hippocampal tissue were significantly decreased in EGE group and increased in IGE group. In addition, the MDA value of IGE group was significantly higher than that of EGE group. (4) 5-BrdU labeling method was used to detect the new neurons in the CA3 area of hippocampus. In the EGE group, a large number of positive cells were stained. In the IGE group, there were almost no positive cells staining, most of them were vacuoles. The control group was not obvious. TUNEL method was used to detect apoptotic neurons. In the CA3 area of hippocampus, there were a large number of positive cells in IGE group, but no positive cells in EGE group, and only a few or individual positive cells in control group. These results suggest that the spatial and emotional learning and memory abilities of mice can be significantly affected by different juvenile growth environments, and the mechanism may be related to oxidative stress, neuronal regeneration and apoptosis.
【学位授予单位】：华中师范大学
【学位级别】：硕士
【学位授予年份】：2008
【分类号】：R33
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