發(fā)布時間：2018-02-10 19:27

  本文關(guān)鍵詞： 葉酸 核黃素 亞甲基四氫葉酸還原酶(MTHFR) 多重聚合酶鏈?zhǔn)椒磻?yīng)-限制性片段長度多態(tài)(Multiplex PCR-RFLP) 胞質(zhì)阻滯微核分析(CBMN) 遺傳穩(wěn)定性　出處：《云南師范大學(xué)》2006年碩士論文　論文類型：學(xué)位論文

【摘要】：葉酸是人體正常發(fā)育的重要微營養(yǎng)物質(zhì)，其涉及dUMP到dTMP的合成，同時通過同型半胱氨酸(HC)合成甲硫氨酸(Met)和S-腺苷甲硫氨酸(SAM)的生化過程影響DNA的甲基化。在葉酸代謝中，亞甲基四氫葉酸還原酶(MTHFR)催化5，，10-亞甲基四氫葉酸(5，10-methylene THF)向5-甲基四氫葉酸(5-methylTHF)轉(zhuǎn)化，MTHFR基因位點(diǎn)突變可導(dǎo)致MTHFR活性降低，同型半胱氨酸水平升高。黃素腺嘌呤二核苷酸(FAD)是MTHFR的輔酶，而FAD的前體為核黃素。因此，葉酸、核黃素缺乏及MTHFR基因多態(tài)性可能對DNA結(jié)構(gòu)和DNA甲基化過程、基因表達(dá)、染色體分離等形成一定的脅迫作用。 本研究采用多重聚合酶鏈?zhǔn)椒磻?yīng)-限制性片段長度多態(tài)(Multiplex PCR-RFLP)技術(shù)篩查MTHFR基因677位點(diǎn)、1298位點(diǎn)基因型在正常個體與乳腺癌患者中的多態(tài)分布特點(diǎn)；以胞質(zhì)阻滯微核分析(CBMN)研究各種MTHFR基因型個體淋巴細(xì)胞在葉酸、核黃素缺乏以及不同濃度組合條件下產(chǎn)生的遺傳與細(xì)胞毒性效應(yīng)，評價不同MTHFR基因型、葉酸與核黃素不同組合對人類基因組穩(wěn)定性的影響。 研究表明： 1、677位點(diǎn)突變純合體(TT)在乳腺癌患者(n=122)和對照組(n=99)中的分布頻率分別為18.03％和9.09％，無顯著性差異；1298位點(diǎn)突變純合體(CC)在乳腺癌患者(n=119)和對照組(n=98)中的分布頻率分別為9.25％和7.15％，也未表現(xiàn)顯著性差異；677、1298位點(diǎn)組合基因型在乳腺癌患者和對照組中的分布頻率無顯著性差異。 2、在本實(shí)驗(yàn)濃度范圍內(nèi)，乳腺癌患者及對照個體遺傳損傷和細(xì)胞損傷指標(biāo)均具有以下趨勢：高葉酸低核黃素組合濃度(HFLR)＜高葉酸高核黃素組(HFHR)＜低葉酸高核黃素組(LFHR)＜低葉酸低核黃素組(LFLR)。提示在葉酸含量較低時，過量的核黃素會對細(xì)胞造成損傷。分析各種因素對損傷的貢獻(xiàn)發(fā)現(xiàn)，葉酸對遺傳物質(zhì)穩(wěn)定性的影響最大，乳腺癌背景及核黃素對遺傳物質(zhì)穩(wěn)定性的影響不顯著。 3、本實(shí)驗(yàn)還討論了基因型、葉酸、核黃素對淋巴細(xì)胞遺傳損傷的影響及三者對造成遺傳損傷的交互作用。結(jié)果發(fā)現(xiàn)葉酸、677位點(diǎn)基因型對細(xì)胞遺傳損傷有顯著影響，而核黃素僅對核質(zhì)橋(NPB)的產(chǎn)生有顯著影響，三者對造成遺傳損傷
[Abstract]:Folic acid is an important micronutrient in the normal development of human body. It involves the synthesis of dUMP to dTMP, and the biochemical process of synthesis of methionine (Meta) and S-adenosine methionine (S- adenosine methionine), which affects the methylation of DNA. Methylene tetrahydrofolate reductase (MTHFR) catalyzes the transformation of 5-methyl-tetrahydrofolate 510-methylene to 5-methyl-tetrahydrofolate (5-methyl-tetrahydrofolate). The mutation of MTHFR gene site can lead to the decrease of MTHFR activity and increase of homocysteine level. Flavin adenine dinucleotide (Fad) is a coenzyme of MTHFR. Therefore, folic acid, riboflavin deficiency and MTHFR gene polymorphism may exert some stress on DNA structure and DNA methylation, gene expression and chromosome segregation. In this study, multiplex polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique was used to screen the polymorphism distribution of MTHFR gene 677 locus and 1298 locus in normal individuals and breast cancer patients. Cytoplasmic block micronucleus analysis was used to study the genetic and cytotoxic effects of individual lymphocytes of various MTHFR genotypes on folic acid, riboflavin deficiency and combination of different concentrations, and to evaluate different MTHFR genotypes. Effects of different combinations of folic acid and riboflavin on the stability of human genome. Research shows that:. The distribution frequencies of 1,677 locus homozygote in breast cancer patients were 18.03% and 9.09, respectively. There was no significant difference in the frequency of 1,677 locus mutation homozygotes in breast cancer patients (n = 119) and control group (n = 9.25%). There was no significant difference in genotype distribution between breast cancer patients and controls. 2, within the concentration range of this experiment, The genetic damage and cell damage index of breast cancer patients and control individuals showed the following trends: high folic acid low riboflavin concentration (HFLR) < high folate high riboflavin group (HFHRs) < low folate high riboflavin group (LFLRR) < low folate low riboflavin group (LFLRR). When folic acid content is low, Analysis of the contribution of various factors to the damage found that folic acid had the greatest influence on the stability of genetic material, while the background of breast cancer and riboflavin had no significant effect on the stability of genetic material. 3. The effects of genotype, folic acid and riboflavin on genetic damage of lymphocytes and their interaction with genetic damage were also discussed. Riboflavin only had a significant effect on the production of NPB, and three of them caused genetic damage.
【學(xué)位授予單位】：云南師范大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2006
【分類號】：R346

【引證文獻(xiàn)】

相關(guān)碩士學(xué)位論文 前2條

1 何晶偉;2型糖尿病患者血漿同型半胱氨酸相關(guān)因素分析及葉酸、維生素B_（12）、核黃素干預(yù)效果研究[D];華北煤炭醫(yī)學(xué)院;2010年

2 梁雅麗;葉酸、p16甲基化、MeCP2蛋白表達(dá)在宮頸癌變中的作用[D];山西醫(yī)科大學(xué);2010年

本文編號：1501258