【摘要】 该文旨在研究雌激素缺乏不同时间段对APP/PS1双转基因小鼠学习记忆及海马区细胞增殖和成熟的影响及探究潜在的机制。将3月龄APP/PS1双转基因AD雌性小鼠行双侧卵巢切除(AD-OVX),以假手术AD小鼠(AD-Sham)及同月龄正常野生型小鼠(WT)作为对照,于术后1周(模拟绝经早期)和3月(模拟绝经中晚期), Morris水迷宫行为测试结果显示,在APP/PS1双转基因AD小鼠中, OVX后1周, AD-OVX组与AD-Sham组比较,其逃避潜伏期、搜索路径以及穿越平台的次数无明显差异(P>0.05);而OVX后3月, AD-OVX组小鼠找到平台的时间和搜索路径显著延长(P<0.05),穿越平台的次数也相应减少(P<0.05);子宫重量结果、EDU细胞增殖状况、老年斑、脑内NeuN蛋白和芳香酶的变化水平分别显示,在APP/PS1双转基因AD小鼠中, OVX后1周, AD-OVX组与ADSham组比较,循环雌激素水平无明显变化;小鼠脑内未见老年斑;小鼠海马区新生阳性细胞数量和NeuN的表达反应性增多(P<0.05);此时小鼠脑内芳香酶表达也呈反应性升高(P<0.05)。而OVX后3月, AD-OVX组小鼠循环雌激素水平明显降低(P<0.05);脑内老年斑显著增加(P<0.05);小鼠海马区新生阳性细胞数量和NeuN的表达减少(P<0.05);此时小鼠脑内芳香酶水平也显著降低(P<0.05)。以上结果说明,雌激素缺乏早期可反应性地增加痴呆小鼠海马区细胞的增殖和成熟,对小鼠学习记忆无影响;但随着雌激素缺乏时间的延长,痴呆小鼠出现学习记忆的损害及海马区细胞增殖和成熟减少;该作用可能与脑内芳香酶水平的变化密切相关。更多还原

【Abstract】 To investigate the effects of different estrogen deficiency time on learning, memory and hippocampal cell proliferation, maturation in APP/PS1 double transgenic mice, exploring its possible mechanisms, 3-month-old APP/PS1 double transgenic AD female mice underwent bilateral ovariectomy(AD-OVX), shamoperated AD mice(AD-Sham) and wild-type mice(WT) of the same age were used as controls. 1 week ovariectomy(simulating early menopause) and 3 months(simulating mid-late menopause) respectively, Morris water maze showed that in APP/PS1 double transgenic AD mice, 1 week after OVX, there was no significant difference in escape latency, escape length and passing times between AD-OVX group and AD-Sham group(P>0.05); However, after OVX 3 months, the time and escape length of the AD-OVX group were significantly prolonged(P<0.05), and the passing times were also decreased(P<0.05). uterine weight, EDU, immunofluorescence, Western blot were used to reflect estrogen levels, cell proliferation status, senile plaques, NeuN protein and aromatase levels in the brain of APP/PS1 double transgenic mice respectively. In APP/PS1 double transgenic AD mice, 1 week after OVX, circulating estrogen level was no obvious change. No senile plaques were found in the brain of mice. The number of neonatal positive cells in the hippocampus of mice and the expression of NeuN were increased in reactivity(P<0.05). At this time, the expression of aromatase was also increased(P<0.05). However, after OVX 3 months, the circulating estrogen level was significantly decreased(P<0.05). The senile plaques in the brain were increased significantly(P<0.05). The number of neonatal positive cells and the expression of NeuN in the hippocampus of mice were significantly decreased(P<0.05). At this time, the level of aromatase was decreased significantly(P<0.05). This results indicate that the early estrogen deficiency increases the proliferation and maturation of hippocampus cells in dementia mice reactively, and has no effect on learning and memory in mice. However, with the prolongation of estrogen deficiency, learning and memory impairment and proliferation and maturation cells in hippocampus are reduced in dementia mice. This effect may be closely related to changes in aromatase levels in the brain.更多还原