雌激素对SAMP8小鼠学习记忆及海马CA1区神经元的影响

目的 观察雌激素对SAMP8鼠学习记忆及海马神经元的影响. 方法 将6月龄SAMP8鼠45只分为假手术组(sham组)、去卵巢组(OVX组)和去卵巢+雌激素组(OVX+E组)3组,并用同龄正常老化SAMR1小鼠作为同源对照组.采用Morris水迷宫实验检测小鼠学习记忆能力,苏木素-伊红染色和免疫组织化学显示海马CA1区神经元及神经型一氧化氮合酶(nNOS)阳性神经元的变化,流式细胞术检测其nNOS的表达量. 结果 OVX组与sham组相比,逃避潜伏期明显延长(P<0.05),跨越平台次数显著减少(P<0.05).雌激素补充治疗能改善学习记忆能力,与sham组比较差异无统计学意义(P>0.05);OVX组海马CA1区神经元病变严重,且CA1区nNOS阳性神经元的数量、吸光度和海马nNOS荧光指数(FI)值均低于sham组(P<0.05);给予雌激素后,OVX+E组各项实验结果与OVX组相比差异有统计学意义(P<0.05),与sham组相比,差异无统计学意义(P>0.05). 结论 雌激素能够改善小鼠的学习记忆能力,有效保护海马CA1区的神经元,提高海马CA1区nNOS阳性神经元的表达.

Effects of estrogen on cognitive functions and on the neurons in CA1 region of hippocampus of the SAMP8 mouse

Objective To investigate the effects of estrogen on the cognitive function and on the hippocampus neurons of SAMP8 mouse. Methods Forty five 6-month-old female SAMP8 were divided into three different groups: sham group, OVX group, OVX+E group, and SAMR1 mice were used as comparision of homologization. Morris water maze test was used to test the ability of learning and memory. HE staining and immunohistochemistry technique were used to reveal the neurons and neuronal nitric oxide synthase(nNOS) positive neurons in the CA1 subregion. Flow cytometry was used to detect the quantities of the nNOS in the hippocampus. Results The escape latency of the OVX group was that of the sham group（EM>P/EM><0.05）and the total number of crossing the platform of the OVX group was fewer than that of the sham group（EM>P/EM><0.05）. Estrogen replacement therapy could improve the learning and memory ability（EM>P/EM>>0.05）; The OVX group of the CA1 was significantly changed, and the nNOS positive neurons, average absorbance and the nNOS fluorescence index (FI) of the OVX group of the CA1 were shorter than that of the sham group（EM>P/EM><0.05）. The OVX+E group and the sham group showed no difference in results（EM>P/EM>>0.05）. Conclusion The present study suggests that estrogen can improve the ability of learning and memory, protect