本文選題：體外受精 + 性別失衡�。� 參考：《中國(guó)農(nóng)業(yè)大學(xué)》2016年博士論文

【摘要】：體外受精(in vitro fertilization, IVF)是一種關(guān)鍵的輔助生殖技術(shù),已廣泛應(yīng)用于人類不育治療及家畜優(yōu)良種質(zhì)資源高效利用。盡管絕大部分IVF后代是健康的,但是越來(lái)越多的大樣本人流行病學(xué)調(diào)查數(shù)據(jù)及小鼠、家畜等動(dòng)物模型實(shí)驗(yàn)證據(jù)表明,IVF存在一系列潛在的短期和長(zhǎng)期健康風(fēng)險(xiǎn),例如：流產(chǎn)、早產(chǎn)、出生缺陷、性別比例失衡、較高的代謝疾病甚至癌癥風(fēng)險(xiǎn)。目前,已有觀點(diǎn)認(rèn)為IVF引發(fā)的表觀修飾異常是造成這些健康問(wèn)題的主要因素。然而,這些表觀修飾異常的性質(zhì)以及其在IVF相關(guān)健康問(wèn)題中的作用知之甚少,這使得IVF相關(guān)的問(wèn)題始終不能從根本上解決。在這些健康問(wèn)題中,IVF引發(fā)的性別失衡問(wèn)題受到廣泛的關(guān)注。自1991以年,這一現(xiàn)象在牛、豬和人上得到反復(fù)證實(shí),但是具體機(jī)制一直沒(méi)能得到解析。作為生殖健康的一個(gè)非常重要的指標(biāo),性別比例出現(xiàn)失衡會(huì)對(duì)社會(huì)穩(wěn)定和群體行為造成長(zhǎng)期的嚴(yán)重影響。IVF引發(fā)的性別失衡意味著IVF胚胎發(fā)育存在性別傾向性的發(fā)育缺陷�？紤]到IVF引發(fā)的表觀修飾錯(cuò)誤可能是造成這些健康問(wèn)題的主要原因,我們推測(cè)IVF可能擾亂了性別特異性的表觀修飾事件,進(jìn)而引起性別傾向性的發(fā)育缺陷及出生性別比例失衡。在此,利用小鼠、兔子、牛為研究模型,通過(guò)足夠的樣本數(shù)量(每組n500)首次證實(shí)小鼠IVF胎兒存在出生性別比例失衡問(wèn)題(57.17%vs.50.89%),這是由于圍植入期雌性胚胎傾向性的發(fā)育異常所致；此外,發(fā)現(xiàn)雌性IVF附植前胚胎存在Xist表達(dá)抑制和印跡X染色體失活(imprinted X-chromosome inactivation, iXCI)不足的表觀修飾錯(cuò)誤。通過(guò)功能性補(bǔ)償實(shí)驗(yàn)校正了IVF出生性別比例,證實(shí)IVF附植前胚胎中Rnf12/Xist基因低表達(dá)引發(fā)iXCI不足,造成圍植入期雌性傾向性地發(fā)育異常,導(dǎo)致出生性別失衡。最終,發(fā)現(xiàn)在胚胎體外培養(yǎng)液中適時(shí)添加適量的視黃酸可以校正IVF引發(fā)的iXCI不足問(wèn)題,并有效地校正出生性別比例。該研究表明IVF引起的表觀錯(cuò)誤在IVF引起的健康問(wèn)題中具有重要作用,揭示這些表觀錯(cuò)誤有助于預(yù)防IVF健康問(wèn)題。此外,比較E3.5、E7.5和E10.5三個(gè)重要發(fā)育階段的體內(nèi)胚胎(in vivo, IVO)和IVF胚胎的microRNA-seq數(shù)據(jù),發(fā)現(xiàn)失調(diào)的microRNAs主要通過(guò)調(diào)控與癌癥發(fā)生、遺傳信息加工、葡萄糖代謝、細(xì)胞骨架組成及神經(jīng)發(fā)生等過(guò)程的基因。進(jìn)一步,發(fā)現(xiàn)IVF組胚胎中僅有miR-199a-5p從E3.5到E10.5持續(xù)低表達(dá)。通過(guò)功能性缺失與補(bǔ)償性實(shí)驗(yàn),證實(shí)IVF引發(fā)的miR-199a-5p低表達(dá)是造成IVF胚胎糖酵解率高、發(fā)育潛能降低、附植后胚胎存活率低的主要原因。綜上,預(yù)防m(xù)iR-199a-5p低表達(dá)可能是改善IVF圍植入期胚胎發(fā)育的有效策略。本研究表明IVF操作及環(huán)境引發(fā)的表觀修飾錯(cuò)誤是導(dǎo)致IVF胚胎及出生后代健康問(wèn)題的主要原因,發(fā)現(xiàn)并校正這些表觀錯(cuò)誤可有效預(yù)防這些健康問(wèn)題。這一思想對(duì)于該領(lǐng)域的研究具有指引作用。將來(lái)針對(duì)其他的IVF健康問(wèn)題,仍需要大量研究探索是由哪些具體的表觀修飾錯(cuò)誤引發(fā)的,進(jìn)而提出針對(duì)性的解決方案。最終,實(shí)現(xiàn)IVF更加安全地應(yīng)用。
[Abstract]:In vitro fertilization (IVF) is a key assisted reproductive technology. It has been widely used in the treatment of human infertility and the efficient utilization of fine germplasm resources of domestic animals. Although the vast majority of the offspring of IVF are healthy, more and more large samples of epidemiological survey data and experimental evidence of animal models, such as mice and livestock, are used. IVF has a series of potential short-term and long-term health risks, such as abortion, preterm birth, birth defects, gender imbalance, higher metabolic disease and even cancer risk. At present, there is a view that apparent modification abnormality caused by IVF is the main factor causing these health problems. However, the nature of these apparent abnormalities and the nature of these apparent modifications, There is little knowledge about the role of IVF related health problems, which makes IVF related problems never fundamentally solved. In these health problems, the problem of gender imbalance caused by IVF is widely concerned. Since 1991, this phenomenon has been repeatedly proved in cattle, pigs and people, but the specific mechanism has not been resolved. As a very important indicator of reproductive health, the gender imbalance in the long-term serious impact of.IVF on social stability and group behavior is a gender imbalance in the development of IVF embryos. Considering the apparent mistaken errors caused by IVF may be the main cause of these health problems. For reasons, we speculate that IVF may disrupt sexual specific apparent modification events, resulting in sexual developmental defects and the imbalance of birth sex ratio. Here, mice, rabbits and cattle are used to study models with sufficient samples (each group of N500) for the existence of sex ratio imbalance in the IVF fetus (57.17% Vs.50.89%), this is due to the tendency of abnormal development of female embryos in the peri implantation period. In addition, the apparent modification errors of Xist expression inhibition and imprinting of X chromosome inactivation (imprinted X-chromosome inactivation, iXCI) in female preimplantation embryos were found. The sex ratio of IVF birth was corrected by functional compensation experiments. The low expression of Rnf12/Xist gene in IVF preimplantation embryos leads to the deficiency of iXCI, which causes the female tendency to develop abnormality in the peri implantation period, leading to the birth sex imbalance. Finally, it is found that proper addition of retinoic acid in the embryo culture medium can correct the problem of iXCI deficiency caused by IVF and effectively correct the sex ratio of birth. The apparent error caused by the apparent IVF plays an important role in the health problems caused by IVF. It is revealed that these apparent errors contribute to the prevention of IVF health problems. In addition, the microRNA-seq data of the three important developmental stages of the body embryos (in vivo, IVO) and IVF embryos of E3.5, E7.5 and E10.5 are compared. Gene processing, genetic information processing, glucose metabolism, cytoskeleton composition and neurogenesis. Further, it was found that only miR-199a-5p from E3.5 to E10.5 remained low in IVF embryos. Through functional deletion and compensatory experiments, the low expression of miR-199a-5p caused by IVF was the high glycolysis rate and developmental potential of IVF embryos. The main reason for lower survival rate of implanted embryos is that the prevention of low expression of miR-199a-5p may be an effective strategy to improve the development of IVF peri implantation embryos. This study shows that the apparent modification errors caused by IVF operation and environment are the main causes of the health problems of IVF embryos and offspring, and the apparent errors can be found and corrected. Effective prevention of these health problems. This idea has a guiding role in the field of research. In the future, there is still a lot of research and Exploration on other IVF health problems, which are caused by specific apparent modification errors, and then put forward targeted solutions. Finally, the implementation of IVF is more secure.
【學(xué)位授予單位】：中國(guó)農(nóng)業(yè)大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類號(hào)】：R714.8;S814.8
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本文編號(hào)：1942947