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The Ultrastructural Features of Hippocampal Neuron of CA1 and Subfornical Organ in Mice with Vascular Dementia

Author: YueHongJuan
Tutor: LvPeiYuan
School: Hebei Medical University
Course: Neurology
Keywords: Vascular Dementia Mice Neurons Hippocampal CA1 region Subfornical Ependymal Transmission electron microscopy Scanning electron microscopy
CLC: R749.16
Type: Master's thesis
Year: 2011
Downloads: 40
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Abstract

Objective: vascular dementia (vascular dementia, VD) and acquired cognitive dysfunction syndrome caused by brain dysfunction caused by cerebrovascular diseases. In recent years, with the aging of the population development and the continuous improvement of the cure rate of stroke, VD incidence presents a clear upward trend, a serious threat to the health of the elderly, but also to society caused heavy mental and economic burden . According to reports, VD senile dementia and hope for the treatment of dementia diseases preventable if early treatment can delay or even reverse the disease development. Therefore, to explore and to clarify the pathogenesis of VD important value and theoretical significance for the clinical development of more rational treatment programs. Learning and memory is the senior activities of the brain. Learning experience and skills obtained, and the memory is the preservation and reproduction of the experience and skill, they are two different but closely linked to neural biological processes. Currently considered higher cognitive functions such as learning and memory, the hippocampus is closely related to whether or not its normal neuronal morphology has important implications for the formation and maintenance of learning and memory. Subfornical organ (subfornical organ, SFO) is located between the lateral ventricles and the third ventricle, the the susceptibility room weeks the organ (senory circumventricular organs SCVOs), one for the site where the blood-brain barrier is not complete, so is the brain chemical signal transduction important sites, immune molecules have an important role in the monitoring. In addition, it is an effective interface for the exchange of information between the blood and central nervous system, neuroendocrine, neuroimmune and signal transduction and other physiological functions are closely related homeostasis mechanism plays an important role in the regulation. This experiment to establish repeated ischemia - reperfusion VD mouse model, mice hippocampus CA1 neurons pathological changes and SFO scanning electron microscope characteristics observed VD, from the angle of the degree of cell biology to explore the pathogenesis of VD. Methods: The study is divided into three parts. Kunming mice as the object of study, the use of bilateral carotid artery ligature method three times repeatedly ischemia - reperfusion prepared VD model and set up the sham group; modeling days 29 and 30 after the first part, the use of step down test and water maze tests of learning and memory tests were two groups of mice, observed behavioral differences of the two groups of mice. And analyzed using SPSS 13.0 statistical software are compared using the t test, P lt; 0.05 or P lt; 0.01 considered statistically significant. Second and third part of a 3% poly-formaldehyde 1% glutaraldehyde fixed mouse brain tissue as the research object, respectively, using electron microscopy and scanning electron microscopy to observe the brain of a mouse hippocampal CA1 neurons and SFO super The micro-structure, the two groups were compared the difference. Results: behavioral evaluation of the two groups of mice model 1.1 academic postoperative day 29, respectively jumping test and water maze test, the test jumping test of reaction time (sec) and the number of errors (number/5min) as academic travel the entire distance of the water maze test time (sec) and the number of errors (number/3min) as academic performance. The jumping test results show: (1) the reaction time of the sham group (21.79 ± 14.94) s and the reaction time of the learning phase of VD model group mice (54.68 ± 26.20) s was significantly longer (P lt; 0.01); (2 ) compared with the sham group, the number of errors (2.79 ± 1.22), VD model group mice learning phase the number of errors (4.05 ± 1.99) was significantly increased (P lt; 0.05). Water maze test results show that: (1) with the sham group travel the entire distance (73.67 ± 19.65) s compare VD model group travel the entire distance learning phase in mice (111.36 ± 26.04) s was significantly longer (P lt; 0.01 ); (2) compared with the sham group, the number of errors (4.08 ± 1.28), VD model group mice learning phase the number of errors (7.18 ± 3.22) was significantly increased (P lt; 0.01). These results suggest that the academic performance of the VD model group than in the sham group reduce. Of 1.2 memory scores after 30 days were jumping test and water maze test, the test platform test latency time (sec) and the number of errors (number/5min) as memory performance, travel the entire distance of the water maze test time (sec) and The number of errors (number/3min) as memory performance. The jumping test results show: (1) the latency of the sham group (174.50 ± 49.91) s VD model group mice memory latency stage (79.45 ± 7.96) s was significantly shorter (P lt; 0.01); (2 ) compared with the sham group, the number of errors (2.75 ± 1.26), VD model group stage of memory in mice the number of errors (4.27 ± 2.21) was significantly increased (P lt; 0.01). Water maze test results show that: (1) with the sham group travel the entire distance time (65.17 ± 13.27) s VD model group mice memory stage travel the entire distance (104.09 ± 28.38) s was significantly longer (P lt; 0.01 ); (2) compared with the sham group, the number of errors (3.42 ± 1.44), VD model group stage of memory in mice the number of errors (5.23 ± 2.56) was significantly increased (P lt; 0.01). These results suggest that the memory performance of the VD model group decreased compared with sham group. 2 electron microscope: 2.1 Transmission electron microscopy observations: (1) sham group: mouse hippocampal CA1 area neuronal morphology normal, uniform distribution of chromatin-rich organelles in the cytoplasm. (2) model group: mouse hippocampal CA1 neurons degeneration, nuclear membrane irregularities, edge blur nucleus enlargement; reduced organelle, mitochondrial degeneration, the most of the ridge and membrane fusion, blurred; rough endoplasmic The visible particles fusion or degranulation endoplasmic reticulum, free ribosomes slightly reduced. The results suggest that the VD model mouse hippocampal CA1 neurons severe injury. 2.2 Scanning electron microscopy results: (1) sham group: SFO surface cilia scarce, most of the area with no or sparse single cilia the cilia surrounding brain regions are more clear ventricle surface boundaries. Ependymal cells visible their rooms, each ependymal cells showed a cobblestone-like bulge cell body sizes, a diameter of about 3-10um clear boundaries between cells; ependymal cells and some smooth surface, some visible on the surface of dense microvilli structure; rich ependymal membrane structure, visible minority ependymal membrane neuron-like cells, and some surface contains 2-3 projections, you can still see the secretory granules, the small number of sizes. (2) model group: SFO surface uneven, ependymal membrane cell surface depressions, cell shape becomes irregular, and various forms of ill-defined in the cell, the ependymal microvilli membrane cells significantly reduced or even disappear, cell secretion relatively large particles, reduced ciliary structure. The results suggest that the the VD model mice SFO ependymal significant pathological changes. Conclusion: The success of an experiment to establish the VD model in mice, after jumping test, water maze test confirmed that the barriers to of VD mice with learning and memory function, able to simulate the clinical VD mental retardation, is a reliable VD animal models , in-depth study of the VD is feasible. 2 transmission electron microscopy observed the VD model mouse hippocampal CA1 neurons severe damage and scanning electron microscopy to SFO ependymal lesions, suggesting that these pathological changes involved in the pathogenesis of VD.

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