雌激素替代治疗对中老年卵巢切除大鼠认知能力及海马内有髓神经纤维髓鞘作用的研究

发布时间：2018-04-03 16:19

本文选题：雌激素替代治疗　切入点：髓鞘　出处：《重庆医科大学》2014年硕士论文

【摘要】：已有大量研究表明，雌激素可直接作用于中枢神经系统，对学习、记忆、情感等功能有重要影响。流行病学结果显示，，绝经后女性罹患阿尔茨海默病（Alzheimer's disease,AD）的风险明显高于男性；且在围绝经期使用雌激素治疗可以延缓AD的发生，提高老年大脑的认知能力。我们选用中老年雌性大鼠行双侧卵巢切除术（ovariectomy，OVX），将成功去势的大鼠随机分为两组，雌激素替代治疗组（OVX+E组）给予17-β雌二醇皮下注射，安慰剂对照组（OVX+O组）给予安慰剂皮下注射。运用Morris水迷宫测试大鼠空间记忆能力；并运用透射电子显微镜和新的体视学方法研究大鼠海马CA1区有髓神经纤维髓鞘的改变。第一部分 1.材料与方法 1.119只雌性SD大鼠（10～12月龄）行双侧卵巢切除术，术后连续阴道涂片及测定循环雌激素浓度筛选成功去势大鼠，随机分为OVX+E组（10只）和OVX+O组（9只）。 1.2OVX+E组给予连续4周17-β雌二醇皮下注射，OVX+O组给予连续4周安慰剂皮下注射。最后一天注射后测定大鼠循环雌激素浓度，分离取出子宫进行称重。 1.3运用Morris水迷宫测试两组大鼠的空间记忆能力。 2.结果 2.1OVX+O大鼠体内循环雌激素水平显著低于OVX+E组大鼠（P0.05）, OVX组大鼠的子宫较OVX+E组大鼠显著萎缩（P0.05）。 2.2OVX+E组大鼠Morris水迷宫的平均潜伏期较OVX+O组大鼠显著性缩短（P0.05）。第二部分 1.材料与方法 1.1从OVX+E组随机挑选6只、OVX+O组随机挑选5只大鼠大脑半球制作1mm连续切片，并用解剖显微镜拍照。 1.2在连续脑片上随机抽取5～7块包含海马CA1的组织块制成超薄切片，每张切片随机抽取5～10个视野在透射电子显微镜下放大20000倍拍照，每只动物共拍摄50张照片。 1.3运用体视学方法计算海马CA1体积、CA1有髓神经纤维及其髓鞘体积。 1.4测量海马CA1内有髓神经纤维直径、有髓神经纤维轴突直径及有髓神经纤维髓鞘厚度。 2.结果 2.1OVX+O组海马CA1体积为26.83±1.17mm3，OVX+E组大鼠海马CA1体积为27.85±1.15mm3，两组之间无显著性差异（P0.05）。两组大鼠的有髓神经纤维体积不存在显著性差异（P0.05）。两组大鼠的有髓神经纤维髓鞘体积也没有显著性差异（P0.05）。 2.2OVX+E组大鼠海马CA1有髓神经纤维平均直径与OVX+O组的比较无显著性差异（P0.05），两组大鼠有髓神经纤维轴突平均直径的比较亦不具有显著性差异（P0.05）。 2.3OVX+E组大鼠直径为0.6~0.7μm的有髓神经纤维髓鞘厚度比OVX+O组大鼠显著性增加14.1%（P0.05）。OVX+E组大鼠直径为0.8~0.9μm的有髓神经纤维直径与轴突直径差较OVX+O组大鼠显著性增加18.2%（P0.05）。全文结论 1.连续4周雌激素替代治疗可以改善中老年大鼠的空间参考记忆能力。 2.雌激素替代治疗对中老年大鼠海马CA1体积没有显著性影响。 3.获得了雌激素缺乏及雌激素替代治疗的中老年大鼠海马CA1内有髓神经纤维体积、髓鞘体积、髓鞘厚度的参数，为以后研究雌激素替代治疗延缓大脑衰老、治疗神经退行性疾病等提供了重要的科学依据。 4.雌激素替代治疗可以防止海马内有髓神经纤维髓鞘丢失和/或促进髓鞘形成增加，其中以中等直径的有髓神经纤维髓鞘改变为主。
[Abstract]:A large number of studies have indicated that estrogen can act directly on the central nervous system, learning, memory, emotion has an important influence function. Epidemiological results show that postmenopausal women suffering from Alzheimer's disease (Alzheimer's, disease, AD) the risk is significantly higher than male; and in perimenopausal estrogen therapy can delay the occurrence of AD, improve cognitive ability the old brain. We use in aged female rats underwent bilateral ovariectomy (ovariectomy, OVX), the rats were randomly divided into two groups successfully ovariectomized, estrogen replacement therapy group (OVX+E group) received 17- subcutaneous injection of estradiol, placebo control group (group OVX+O) received placebo subcutaneously by Morris water maze. To test the spatial memory of rats; and by transmission electron microscopy and stereological methods in rat hippocampal CA1 area of myelinated nerve fiber myelin changes.
Part one
1. materials and methods
1.119 female SD rats (10~12 months old) underwent bilateral ovariectomy, and determination of circulating estrogen concentration in ovariectomized rats successfully screened continuous vaginal smear after surgery, were randomly divided into OVX+E group (10 rats) and OVX+O group (9).
Group 1.2OVX+E was given subcutaneous injection of 17- beta estradiol for 4 weeks. OVX+O group was given subcutaneous injection of placebo for 4 weeks. After the last day, the concentration of circulating estrogen was measured, and the uterus was removed and weighed.
1.3 the Morris water maze was used to test the spatial memory ability of the two groups of rats.
2. results
The level of circulating estrogen in 2.1OVX+O rats was significantly lower than that in group OVX+E (P0.05), and the uterus of group OVX rats was significantly atrophied than that in group OVX+E (P0.05).
The average latency of Morris water maze in group 2.2OVX+E rats was significantly shorter than that in group OVX+O (P0.05).
The second part
1. materials and methods
1.1 from group OVX+E, 6 were selected randomly. Group OVX+O randomly selected 5 rat cerebral hemispheres to make 1mm continuous slices and photographed with an anatomical microscope.
1.2 randomly selected 5~7 blocks containing hippocampal CA1 from the continuous brain slices to make ultrathin slices. 5~10 slices were randomly selected from each slice, and 20000 times were taken up under transmission electron microscope. 50 photos were taken by each animal.
1.3 the volume of hippocampal CA1 was calculated by stereological method, and myelinated nerve fiber and its myelin sheath volume were found in CA1.
1.4 the diameter of the myelinated nerve fibers in the hippocampal CA1, the diameter of the myelinated nerve fiber axons and the myelin sheath thickness of the myelinated nerve fibers were measured.
2. results
In group 2.1OVX+O, the volume of CA1 was 26.83 + 1.17mm3, OVX+E group CA1 of the rat hippocampus volume was 27.85 + 1.15mm3, there was no significant difference between the two groups (P0.05). The two groups of rats of myelinated nerve fiber volume had no significant difference (P0.05). The two groups of rats of myelin volume there were no significant differences (P0.05).
The mean diameter of CA1 myelinated nerve fibers in hippocampus of 2.2OVX+E group was not significantly different from that of OVX+O group (P0.05). There was no significant difference in mean diameter of myelinated nerve axons between two groups (P0.05).
In group 2.3OVX+E, myelin sheath thickness of myelinated nerve fibers with diameter of 0.6~0.7 mu m in group A was significantly increased by 14.1% (P0.05) than that in group OVX+O, and the diameter and diameter of myelinated nerve fibers in 0.8~0.9 group were significantly increased by 18.2% (P0.05) than those in OVX+O group.
Full text conclusion
1. consecutive 4 weeks of estrogen replacement therapy can improve the spatial reference memory ability of middle and old aged rats.
2. estrogen replacement therapy had no significant effect on the volume of CA1 in the hippocampus of middle aged and old rats.
3. the lack of estrogen and estrogen replacement therapy of CA1 in hippocampus in aged rats myelinated nerve fibers in the volume, volume of myelin, myelin sheath thickness parameters, for the study of estrogen replacement therapy to slow brain aging, treatment of neurodegenerative diseases provides an important scientific basis.
4. estrogen replacement therapy can prevent myelin sheath loss and / or myelin formation in the hippocampus, and myelin sheath changes in medium diameter myelinated nerve fibers.

【学位授予单位】：重庆医科大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：R713.6

【参考文献】