| Objective:Along with the accelerating population aging process, thefertility rate declining and the life expectancy of per capita rising,the emptynest solitary phenomenon has become increasingly prominent and one of theimportant problems that cannot be ignored in the process of our agingpopulation.Through enriched environment intervention, to observe theSAMP8mices on the improvement of their cognitive function, to observe theeffect on the SAMP8mices of social interaction (social or solitary) singlely,and to observe and analyze the effects on hippocampal neurons of enrichedenvironment and social interaction (social or solitary).Imagining todemonstrate the reliability nursing measures and mechanisms of enrichedenvironment and social interaction on elderly patients with dementia, toprovide scientific and objective basis for the early intervention and preventionof alzheimer’s patients.Methods:Thirty-two6-month-old male SAMP8were randomly dividedinto enriched environment and living in groups group(A),enrichedenvironment and living alone group(B),general environment and living ingroups group(C), general environment and living alone group(D).The rest ofthe conditions in each group were similar,feeding in conditions of normaltemperature, light, drinking water, diet and environment.The environmentalintervention time was6weeks totaly.1.Morris water maze(MWM) test. After injection, the SAM mice wereraised2days under the environment of labyrinth laboratory first. Training wasprogressed in every morning between8:00~12:00. The fixed position locationunderway trials: The MWM was dividing equally for4quadrants; the plat wasput among them in one quadrant. The mouse went into water from everyquadrant midpoint towards the wall in pond, and the video frequency acquisition system tracken and recorded escape latency(escape latency:s).Eachmouse was trained in turn in the four quadrants per day. After5days removedthe plat and undertaken space exploring trial, mouse was pointed to the wallinto the water from the furthest away from the platform, we observed theswimming trajectory of the mouse and taken notes the times that the mouseacrossing span flat roof in120s.2.Preparate tissue slices and observe.4mice of every group were takenout, broken right auricle and perfused quickly with0.9%normal saline andsubsequently fixed with4%parafom via left ventricle. The hippocampus wastaken between superior colliculus and optic chiasma to make4sets of paraffinsections using for HE staining, Nissl staining, anti-NMDAR1immunohistochemical staining and negative control.3.The ultramicrostructure observation in CA1region of hippocampalneurons. The hippocampus was dissociated after perfusion, fixed in4%precooling glutaraldehyde, and cutted into thin slice of1mm, then into <1mm31h once more, fixed by osmium acid, dewated, embed and sectioned at athickness of50nm. Cut it using the LKB-5ultramicrotome, thickness50nm.Plumbum-uranium staining, observed the ultrastructure change of neuron byusing the transmission electron microscop.Results:1.In the MWM test, the escape latency of enriched environment andliving in groups group was significantly shoter than that in the other groups(P<0.05), and the times of span flat roof was the most (P<0.05). Enrichedenvironment, living in groups can improve the cognitive functions,and therewas significant difference compared with general environment and living ingroups(P<0.05).2.HE staining results: compared with other groups, in generalenvironment and living alone group neurons of hippocampus CA1area, itspathological change was the most serious, rendering diffuse vacuolesdegeneration, cell swelling, nuclear hyperchromatism and pyknoticphenomenon. but in enriched environment and living in groups group neurons had normal structure than other groups, more layers of cells, neurons arrangedrelatively tight and neat, clear hierarchy.3.Nissl staining results: neurons of hippocampus in enriched environmentand living in groups group were morphological regularly, rich and dense, withstatistical difference (P<0.05). while the neurons in the enriched environmentand living alone group were fairly sparse,and its volume were smaller.Neurons in general environment and living alone group weresparse,disorder,loss seriously,and presented karyopyknosis, turbidness andanachromasis, with less and even desolved Nissl bodies, its neurons weremuch fewer than those in the enriched environment and living alonegroup,with significant statistical difference (P<0.05).Compared with thegeneral environment and living alone group the Nissl bodies in generalenvironment and living in groups group were increased,and the neuronnumber increased, with statistical difference(P<0.05).4.With anti-NMDAR immunohistochemistry, the express of immunereaction products were the least in general environment and living alonegroup,neurons arranged loosely, and lightly dyed;while the express products inenriched environment and living in groups group were much more than othergroups, neurons arranged closely and were deeply dyed.Analysis of opticaldensity value showed the optical density value in enriched environment andliving in groups group was the highest, while in general environment andliving alone group,it showed a minimum set of optical density value.5.Electron microscopy ultrastructure observation: the nuclear membraneof neurocyte in enriched environment and living in groups group was clear,smooth, with proportionate cytoplasm, low electron density.Karyotype ofneurons in enriched environment and living alone group were irregular,organelles capacity were less, and a little lipofuscins deposited.While in thegeneral environment and living in groups group,the gap between nuclearsexpansion, nucleoplasmic were mildly enrichment,and a little lipofuscinsdeposited.And in the general environment and living alone group,nuclearmembrane disappeared melting partially, cytoplasm swelling pale, forming irregular crumbs of high electron density, lipofuscins deposited,and organellesdecreased significantly.Conclusions:1.Rich environment and social (increase social interaction) can improvethe cognitive function of SAMP8mouse.2.Rich environment and social (increase social interaction) can improvethe pathological injury in hippocampal neuron of SAMP8mouse, reduce thedegeneration and loss of Nissl bodies，neuron and organelles.3.Rich environment and social (increase social interaction) can increaseNMDAR1protein expression in hippocampal CA1area.4.The effects of rich environment and social (increase social interaction)on protecting hippocampal neurons and improving the cognitive functions ofthe SAMP8mouse were independent,no interaction between them. |
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