本文選題：有髓神經(jīng)纖維 + 海馬結(jié)構(gòu)��； 參考：《重慶醫(yī)科大學(xué)》2010年碩士論文

【摘要】： 海馬結(jié)構(gòu)在學(xué)習(xí)和記憶中起著重要作用。衰老引起的海馬結(jié)構(gòu)功能的退化最初認(rèn)為與海馬神經(jīng)元的死亡有關(guān)。但是,已有研究表明衰老并不會引起海馬結(jié)構(gòu)內(nèi)顯著的神經(jīng)元死亡。由此推斷,空間記憶能力的減退可能與神經(jīng)纖維的退化有關(guān)。大量的研究表明,豐富生存環(huán)境可以提高動物的空間記憶能力、增加樹突分支、促進(jìn)膠質(zhì)細(xì)胞生成、促進(jìn)海馬齒狀回新生神經(jīng)元形成和增加神經(jīng)營養(yǎng)因子mRNA表達(dá)等。動物的空間記憶能力在中老年時期開始下降,因此,在此階段采取行為學(xué)手段的干預(yù)可能有助于預(yù)防或延緩記憶能力的下降。豐富生存環(huán)境干預(yù)是所有行為學(xué)干預(yù)手段中最簡單易行的,那么豐富生存環(huán)境干預(yù)對于中老年時期空間記憶能力降低是否有幫助,同時豐富生存環(huán)境干預(yù)對中老年海馬結(jié)構(gòu)有髓神經(jīng)纖維是否有影響,國內(nèi)外尚未見報道。本研究旨在探討豐富生存環(huán)境對中老年雌、雄性大鼠空間記憶能力、海馬結(jié)構(gòu)及其內(nèi)有髓神經(jīng)纖維的影響。本實驗首先運(yùn)用Morris水迷宮探討豐富生存環(huán)境干預(yù)對中老年雌、雄性大鼠行為學(xué)的作用,然后運(yùn)用透射電子顯微鏡和體視學(xué)方法定量研究豐富生存環(huán)境下中老年雌、雄性SD大鼠海馬結(jié)構(gòu)總體積、海馬內(nèi)有髓神經(jīng)纖維總長度、總體積和平均直徑的改變。 1材料與方法 1.1清潔級14個月Sprague-Dawley雌性大鼠22只。隨機(jī)分為豐富生存環(huán)境組12只和標(biāo)準(zhǔn)環(huán)境組10只。清潔級14個月Sprague-Dawley雄性大鼠22只。隨機(jī)分為豐富生存環(huán)境組12只和標(biāo)準(zhǔn)環(huán)境組10只。豐富生存環(huán)境干預(yù)后,隨機(jī)抽取豐富生存環(huán)境組雌、雄各5只和標(biāo)準(zhǔn)環(huán)境組雌、雄各5只進(jìn)行后續(xù)行為學(xué)測試以及形態(tài)學(xué)分析。 1.2豐富生存環(huán)境組(enriched environment group, EE組)大鼠飼養(yǎng)于大箱子中(120 cm×60 cm×50 cm)飼養(yǎng), 12只/箱,室溫21±2℃,12 h光照與12 h黑夜交替,給予足夠的食物和水。箱內(nèi)設(shè)有各式各樣的物體,每周更換保持新奇感。短期干預(yù)時間為4個月。將標(biāo)準(zhǔn)環(huán)境組(standard environment group,SE組)大鼠在普通標(biāo)準(zhǔn)箱中(40 cm×30 cm×30 cm)飼養(yǎng),5只/箱,給予足夠的食物和水。箱內(nèi)不設(shè)任何物體。飼養(yǎng)時間為4個月。 1.3干預(yù)結(jié)束后,用Morris水迷宮進(jìn)行連續(xù)5天的空間記憶能力的測試。前四天為隱藏平臺實驗,第五天為可見平臺實驗。記錄動物的尋臺時間(從入水到找到平臺且四肢爬上平臺的時間,即潛伏期)。 1.4每只大鼠隨機(jī)抽取一側(cè)大腦半球,再從海馬結(jié)構(gòu)中隨機(jī)抽取4~6個組織塊做成超薄切片,在透射電鏡下每張切片上隨機(jī)抽取15個視野放大9000倍拍照,每只動物拍得75張電鏡照片。 1.5運(yùn)用體視學(xué)方法分別計算出中老年雌、雄組大鼠大腦海馬結(jié)構(gòu)總體積、海馬結(jié)構(gòu)內(nèi)有髓神經(jīng)纖維長度密度和總長度、體積密度和總體積以及有髓神經(jīng)纖維的平均直徑。 2結(jié)果 2.1在隱藏平臺實驗中,18月齡SD雌性大鼠的EE組的潛伏期比SE組顯著縮短(P0.05),雄性大鼠的EE組與SE組的潛伏期之間不存在顯著性差異(P0.05)。在可見平臺試驗中,18月齡雌、雄性大鼠EE組與SE組的潛伏期均沒有顯著性差異(P0.05)。 2.2雌性EE組海馬結(jié)構(gòu)總體積比SE組增加了11.7%,但兩組之間不存在顯著性差異(P0.05)。雄性EE組海馬結(jié)構(gòu)總體積比SE組增加了4.6%,兩組之間也無顯著性差異(P0.05)。 2.3雌性EE組海馬結(jié)構(gòu)內(nèi)有髓神經(jīng)纖維總長度比SE組顯著增加了47.4% (P0.01)。雄性EE組海馬結(jié)構(gòu)內(nèi)有髓神經(jīng)纖維總長度比SE組顯著增加了71.8% (P0.05)。雌性EE組海馬結(jié)構(gòu)內(nèi)有髓神經(jīng)纖維總體積比SE組顯著增加了43.4% (P0.01)。雄性EE組海馬結(jié)構(gòu)內(nèi)有髓神經(jīng)纖維總體積比SE組顯著增加了102.9% (P0.05)。雌性EE組海馬結(jié)構(gòu)內(nèi)有髓神經(jīng)纖維的平均直徑比SE組減少了5.2%,但兩組之間不存在顯著性差異(P0.05)。雄性EE組海馬結(jié)構(gòu)內(nèi)有髓神經(jīng)纖維的平均直徑比SE組增加了33.1%,且差異具有顯著性(P0.01)。雌、雄性EE組和SE組大鼠海馬結(jié)構(gòu)內(nèi)有髓神經(jīng)纖維直徑分布圖表明雌、雄性EE組大鼠有髓神經(jīng)纖維總長度的顯著性增加主要是由于細(xì)小直徑的有髓神經(jīng)纖維增加所致。 全文結(jié)論 1.本實驗首次利用透射電子顯微鏡和體視學(xué)方法定量研究豐富生存環(huán)境下中老年雌、雄性SD大鼠海馬結(jié)構(gòu)總體積、海馬內(nèi)有髓神經(jīng)纖維總長度、總體積和平均直徑的改變,并同時利用Morris水迷宮進(jìn)一步探討了短期豐富生存環(huán)境下雌、雄性中老年大鼠的行為學(xué)改變。 2.本研究發(fā)現(xiàn)短期豐富生存環(huán)境可明顯提高中老年雌性大鼠的空間記憶能力,但不能提高中老年雄性大鼠的空間記憶能力。這一結(jié)果為將來尋找延緩大腦衰老進(jìn)程的行為學(xué)手段提供了重要的理論依據(jù)。 3.本研究首次發(fā)現(xiàn)短期豐富生存環(huán)境能增加中老年雌、雄性大鼠大腦海馬結(jié)構(gòu)內(nèi)有髓神經(jīng)纖維總長度、總體積,增加中老年雄性大鼠大腦海馬結(jié)構(gòu)內(nèi)有髓神經(jīng)纖維的平均直徑。雌、雄性豐富生存環(huán)境組大鼠海馬結(jié)構(gòu)內(nèi)有髓神經(jīng)纖維總長度的顯著性增加主要是由于細(xì)小直徑的有髓神經(jīng)纖維增多所致,這一研究結(jié)果為進(jìn)一步認(rèn)識豐富生存環(huán)境改善大腦功能的機(jī)制提供了重要的形態(tài)學(xué)基礎(chǔ)。
[Abstract]:Hippocampal structure plays an important role in learning and memory. Degeneration of hippocampal structure caused by aging is originally thought to be associated with the death of hippocampal neurons. However, it has been suggested that aging does not cause significant neuronal death in the hippocampus. Thus, the deterioration of spatial memory ability may be associated with the degeneration of nerve fibers. A large number of studies have shown that rich living environment can improve the spatial memory ability of animals, increase the branches of the dendrites, promote the formation of glial cells, promote the formation of hippocampal dentate gyrus, and increase the expression of neurotrophic factor mRNA. The spatial memory ability of the animals began to decline during the middle and old years. Therefore, this stage is taken. Intervention for learning methods may help prevent or delay the decline in memory ability. Rich living environment intervention is the simplest of all behavioral interventions. The purpose of this study was to explore the effect of rich living environment on spatial memory, hippocampal structure and intramedullary nerve fibers in male and female rats. First, the Morris water maze was used to explore the behavior of male and middle aged female and male rats. Then, study the quantitative research methods of enriched environment in aged female by transmission electron microscopy and stereology, male SD rat hippocampus hippocampus volume, the total length of the myelinated fibers, the total volume and the average diameter of the change.
1 materials and methods
1.1 14 month Sprague-Dawley female rats of 14 month cleaning grade were randomly divided into rich living environment group 12 and standard environment group 10. 22 male rats of clean grade 14 months were randomly divided into rich living environment group 12 and standard environment group 10. The rich living environment after the prognosis, random extraction of the survival environment group of female, 5 male, 5 Only 5 females and the standard environment group were followed up for behavioral tests and morphological analysis.
1.2 (enriched environment group, EE) rats were raised in large boxes (120 cm * 60 cm x 50 cm), 12 / box, room temperature 21 + 2 C, 12 h light and 12 h night alternately, giving enough food and water. There were a variety of objects in the box to keep the novelty a week. The short-term intervention time was 4 months. The standard was 4 months. The standard was 4 months. The environmental group (standard environment group, SE group) rats in the normal standard box (40 cm * 30 cm * 30 cm) feeding, 5 / box, give enough food and water. The box without any objects. The feeding time is 4 months.
1.3 after intervention, for 5 consecutive days of spatial memory by Morris water maze test. The first four days for the hidden platform experiment, fifth days for the visible platform experiment. Animal records search time (from entering the water to find the platform and limbs climbed up to the platform in time, latent period).
Every 1.4 rats were randomly selected from one side of the brain hemisphere, in the hippocampus of 4~6 randomly selected tissue blocks into ultrathin sections under transmission electron microscope in each section on 15 randomly selected view 9000 times magnification pictures, each animal took 75 photos.
1.5 using stereological methods were calculated in elderly female male group, the total volume of the structure of hippocampus in rat hippocampus, myelinated fiber length density and total length, volume density and total volume and mean diameter of the myelinated nerve fibers.
2 Results
2.1 in the hidden platform experiment, the incubation period of the EE group in the 18 month old SD female rats was significantly shorter than that in the SE group (P0.05). There was no significant difference between the EE group and the SE group in the male rats (P0.05). In the visible platform test, there was no significant difference in the latency between the EE group and the SE group of the male rats (P0.05).
2.2 female EE group hippocampus total volume increased by 11.7% compared with SE group, but there was no significant difference between the two groups (P0.05). The total volume of the hippocampal formation of male EE was 4.6% higher than SE group, between the two groups had no significant difference (P0.05).
2.3 the total length of myelinated nerve fibers in the hippocampal structure in the female EE group was significantly increased by 47.4% (P0.01). The total medullary nerve fiber length in the hippocampal structure in the male EE group was 71.8% (P0.05) significantly higher than that in the SE group. The total medullary nerve fiber volume in the hippocampal structure in the female EE group increased by 43.4% (P0.01) in the hippocampus structure of the female EE group. In the hippocampus of the male EE group, the hippocampus structure was in the male EE group. The total volume of myelinated nerve fibers increased by 102.9% (P0.05) significantly than that in the SE group. The average diameter of the myelinated nerve fibers in the hippocampal structure in the female EE group was 5.2% less than that in the SE group, but there was no significant difference between the two groups (P0.05). The average diameter of the myelinated nerve fibers in the hippocampal structure of the male EE group was 33.1% higher than that in the SE group, and the difference was significant. (P0.01). Female and male EE group and SE group rats hippocampus with diameter distribution chart shows that female myelinated nerve fibers, male EE rats had a significant increase in the total length of the myelinated fibers with small diameter is mainly due to the increase of the myelinated fibers.
Full text conclusion
1. the experiment was for the first time to use transmission electron microscope and stereological method to quantitatively study the total volume of the hippocampus structure, the total length, the total volume and the average diameter of the medullary nerve fibers in the hippocampus of the male SD rats in the rich living environment, and further explore the female and male in the short term rich living environment by using the Morris water maze. Behavioural changes in old and middle aged rats.
2. the study found that the short-term rich living environment can obviously improve the spatial memory ability of the middle-aged and old female rats, but can not improve the spatial memory ability of the middle aged and old male rats. This result provides an important theoretical basis for the future search for the behavioral means to delay the aging process of the brain.
3. for the first time, we found that a short term rich environment can increase the average diameter of the medullary nerve fibers in the hippocampus of the male rats. The average diameter of the medullary nerve fibers in the hippocampus of the male rats is increased. Significant increase in the degree of the mean diameter of the myelinated nerve fibers increased due to the results of this study provide important morphological basis for further understanding of the enriched environment to improve brain function mechanism.
【學(xué)位授予單位】：重慶醫(yī)科大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2010
【分類號】：R329.45

【引證文獻(xiàn)】

相關(guān)博士學(xué)位論文 前1條

1 趙圓宇;豐富生存環(huán)境對中老年雌性大鼠大腦有髓神經(jīng)纖維及少突膠質(zhì)細(xì)胞的作用[D];重慶醫(yī)科大學(xué);2011年

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本文編號：2047070