本文選題：葉酸 + DNA甲基化��； 參考：《天津醫(yī)科大學(xué)》2017年碩士論文

【摘要】：目的孕期母體的營養(yǎng)狀況與子代發(fā)育之間存在關(guān)聯(lián),葉酸作為一碳單位載體可參與體內(nèi)多種甲基化反應(yīng),而DNA甲基化在子代個體神經(jīng)系統(tǒng)發(fā)育中又起到重要作用。但孕期葉酸干預(yù)是否通過DNA甲基化途經(jīng)調(diào)節(jié)子代神經(jīng)發(fā)育,及其作用的具體基因位點(diǎn)目前尚不明確,本研究擬通過大鼠生殖實驗,探討孕期葉酸營養(yǎng)水平是否通過調(diào)節(jié)細(xì)胞周期蛋白依賴性激酶5(cyclin-dependent kinase 5,CDK5)、Toll樣受體4(Toll-like receptors 4,TLR4)甲基化改善子代幼年大鼠神經(jīng)發(fā)育,為孕期葉酸合理補(bǔ)充提供科學(xué)依據(jù)。方法40只SPF級雌性Sprague-Dawley(SD)大鼠隨機(jī)分為4組:(1)葉酸缺乏組(folate-deficient diet group,DD)飼以葉酸缺乏飼料;(2)葉酸正常組(folate-normal diet group,ND)飼以葉酸正常飼料;(3)葉酸短期補(bǔ)充組(folate-added diet short-period group,FD-S)在合籠交配期飼以葉酸補(bǔ)充飼料10天,其余時間段飼以葉酸正常飼料;(4)孕前孕后葉酸全程補(bǔ)充組(folate-added diet long-period group,FD-L)全程飼以葉酸補(bǔ)充飼料。孕鼠分娩當(dāng)日記作子代新生鼠出生后第1天(Postnatal day 1,PD1),于PD1-PD14,每日監(jiān)測仔鼠的體重變化情況,記錄仔鼠完成各項生理發(fā)育指標(biāo)的達(dá)標(biāo)日齡,采用平面翻正反射、負(fù)性趨地反射、懸吊實驗、懸崖回避反射及感官反射5項指標(biāo)檢測仔鼠神經(jīng)發(fā)育;檢測母鼠血清葉酸、血漿同型半胱氨酸(homocysteine,Hcy)、SAM與S-腺苷同型半胱氨酸(S-adenosylhomocysteine,SAH)含量;檢測仔鼠血清及腦組織葉酸,腦組織Hcy、SAM、SAH水平及DNA甲基轉(zhuǎn)移酶(DNA methyltransferases,DNMTs)活性及總DNA甲基化水平,并檢測仔鼠腦組織CDK5、TLR4啟動子甲基化與表達(dá)水平。結(jié)果孕期葉酸干預(yù)對雌性子代幼年大鼠的早期體重具有一定的影響(P0.05),對子代幼年大鼠的早期生理發(fā)育各項指標(biāo)差異均無統(tǒng)計學(xué)意義(P0.05);孕期葉酸缺乏可使子代幼年大鼠平面翻正反射、負(fù)性趨地反射、懸吊實驗、懸崖回避反射及感官反射等神經(jīng)反射行為出現(xiàn)延遲,葉酸補(bǔ)充可改善其表現(xiàn)。孕期葉酸補(bǔ)充可提高子代新生鼠血清與腦組織中的葉酸含量,降低其腦組織中Hcy,SAH含量,升高SAM/SAH比值;孕期葉酸缺乏則降低仔鼠腦組織葉酸含量、提高了仔鼠腦組織中Hcy、SAH含量,降低了SAM/SAH比值(P0.05)。孕期葉酸補(bǔ)充可提高仔鼠腦組織總DNMTs活性及其m RNA與蛋白表達(dá),提高DNA總甲基化水平;孕期葉酸缺乏則降低總DNMTs活性及其表達(dá),降低DNA總甲基化水平(P0.05)。孕期葉酸補(bǔ)充可以提高CDK5、TLR4基因啟動子區(qū)甲基化水平,從而下調(diào)其表達(dá);孕期葉酸缺乏則降低了CDK5、TLR4基因啟動子區(qū)甲基化水平,促進(jìn)其表達(dá)(P0.05)。結(jié)論本研究結(jié)果顯示孕期葉酸補(bǔ)充可改善子代幼年大鼠神經(jīng)行為學(xué)發(fā)育。機(jī)制研究提示孕期葉酸補(bǔ)充能夠提高子代大鼠血清及腦組織中葉酸、SAM水平,降低Hcy、SAH水平,提高子代大鼠腦組織甲基化潛能及DNMTs活性和總甲基化水平。孕期葉酸補(bǔ)充能夠上調(diào)子代腦組織CDK5、TLR4基因啟動子區(qū)甲基化水平,使其發(fā)生靜默,降低其表達(dá)水平。孕期葉酸補(bǔ)充調(diào)節(jié)CDK5、TLR4基因甲基化改善子代幼年大鼠神經(jīng)行為發(fā)育。
[Abstract]:Objective the relationship between the maternal nutrition status and the offspring development during pregnancy, folic acid as a single carbon carrier can participate in various methylation reactions in the body, and DNA methylation plays an important role in the development of the neural system of the offspring, but whether the intervention of folic acid during pregnancy through DNA methylation through the modulation of modulated nerve development and its effect Specific gene loci are not yet clear. This study is intended to explore whether the level of folic acid nutrition during pregnancy can improve the neurodevelopment of young rats by modulating cyclin dependent kinase 5 (cyclin-dependent kinase 5, CDK5) and Toll like receptor 4 (Toll-like receptors 4, TLR4) during pregnancy. Methods 40 SPF grade female Sprague-Dawley (SD) rats were randomly divided into 4 groups: (1) folate deficiency group (folate-deficient diet group, DD) was fed with folic acid deficiency diet; (2) the normal folic acid group (folate-normal diet group, ND) was fed with Ye Suanzheng constant feed; (3) short term folic acid supplementation group (3) D-S) supplemented with folic acid for 10 days during the mating period and the rest of the time with folic acid normal feed; (4) the whole course of folic acid supplementation after pregnancy (folate-added diet long-period group, FD-L) was fed with folic acid supplementation. Pregnant rats were given birth as a newborn rat first days after birth (Postnatal day 1, PD1), in PD1-PD14, daily prison. The body weight changes of the offspring were measured, and the average age of the offspring was recorded, and 5 indexes were detected by plane reversal reflex, negative chemotactic reflex, suspension test, cliff avoidance reflex and sensory reflex, and serum folic acid, plasma homocysteine (homocysteine, Hcy), SAM and S- adenosine were detected. S-adenosylhomocysteine (SAH) content; detection of serum and brain tissue folic acid, Hcy, SAM, SAH level and DNA methyltransferase (DNA methyltransferases, DNMTs) activity and total DNA methylation level of the brain tissue, and detect the CDK5 of the brain tissue of the offspring and the level of methylation and expression of the TLR4 promoter. Results during pregnancy, folic acid intervened in the female. The early body weight of the young rats had a certain influence (P0.05), and there was no significant difference in the early physiological development indexes of the young adult rats (P0.05). Folic acid supplementation could improve its performance. Folic acid supplementation during pregnancy could increase the content of folic acid in serum and brain tissue of newborn rats, decrease the content of Hcy and SAH in brain tissue, increase the ratio of SAM/SAH, and decrease the content of folic acid in the brain tissue of the offspring, increase the content of Hcy and SAH in the brain tissue of the offspring, and reduce the ratio of SAM/SAH (P0.05). During pregnancy, folic acid supplementation could improve the total DNMTs activity of the brain tissue and the expression of M RNA and protein, increase the total methylation level of DNA, decrease the total DNMTs activity and its expression and decrease the total DNA methylation level (P0.05) during pregnancy, and the folic acid supplementation during pregnancy can improve the methylation level of CDK5, TLR4 gene promoter region and down regulation of the expression of the folic acid supplementation during pregnancy. Folic acid deficiency during pregnancy reduces the level of methylation in the promoter region of CDK5 and TLR4 genes and promotes its expression (P0.05). Conclusion the results of this study suggest that folic acid supplementation during pregnancy can improve the neurobehavioral development of juvenile rats. The mechanism study suggests that folic acid supplementation during pregnancy can improve the level of folic acid, SAM, and decrease Hcy, S in the serum and brain tissue of the offspring of the offspring. AH level, improve the methylation potential and DNMTs activity and total methylation level of the rat brain tissue. During pregnancy, folic acid supplementation can improve the level of methylation of CDK5, TLR4 gene promoter region, make it silent and reduce its expression level. During pregnancy, folic acid supplementation is supplemented by CDK5, TLR4 gene methylation improves the neurologic of young offspring of offspring. For development.

【學(xué)位授予單位】：天津醫(yī)科大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：R715.3

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