多不饱和脂肪酸对神经管畸形和自然流产的影响及机制研究

发布时间：2018-08-01 18:01

【摘要】：神经管畸形(NTD)及自然流产均为胚胎发育过程中出现的疾病。NTD是胚胎神经管无法完成正常闭合而导致的一种先天畸形。叶酸缺乏所引起的叶酸-同型半胱氨酸Hcy)代谢紊乱是导致NTD发生的最主要原因。此外肌醇代谢通路异常、炎症反应等也是导致NTD发生的原因。自然流产是指非人为地在自然状态下发生的流产,其发病原因主要包括染色体异常,感染、免疫及炎症,内分泌功能紊乱,叶酸—Hcy代谢异常等。多不饱和脂肪酸(PUFA)是神经系统的重要结构组分。PUFA代谢产生的类花生酸TXA2、PGI2(二者的稳定代谢产物分别为TXB2及6-keto-PGF1α)能够参与调控营养物质由母亲经胎盘到胎儿的转运。此外,PUFA对叶酸-Hcy代谢通路及炎症反应也具有调控作用。基于前人的这些研究结果,本文提出假设:PUFA能够通过调控类花生酸代谢、叶酸-Hcy代谢、炎症反应以及弥补机体PUFA的不足而对NTD及自然流产的发生起到一定的预防作用。本论文通过病例对照实验分析PUFA与NTD及自然流产的相关性,进而通过动物实验研究PUFA的摄入对子代NTD及流产发病率的影响及其机制。主要研究结果如下:(1)病例对照实验发现胎盘中C18:2n-6、C18:3n-6、C20:3n-6、C18:3n-3、C20:3n-3、C20:5n-3、C22:5n-3 含量过低及 C20:4n-6/C20:5n-3、TXB2/6-keto-PGF1α的比值过高与胎儿NTD发病风险的升高密切相关,表明这些PUFA的缺乏及类花生酸代谢紊乱是NTD的风险因素。(2)病例对照实验发现,孕早期自然流产妇女胎盘绒毛和蜕膜中必须脂肪酸C18:3n-3、蜕膜中总n-3 PUFA、绒毛中必需脂肪酸C18:2n-6的含量均显著低于健康孕妇,表明这些PUFA的缺乏与孕早期自然流产发生的密切相关。孕早期自然流产妇女绒毛中C20:4n-6/C20-5n-3的比值显著高于健康孕妇,而C20:4n-6代谢产生的类花生酸PGI2及C20:5n-3代谢产生的类花生酸HEPE、LTB5、TXB3的水平显著低于健康孕妇,表明胎盘绒毛中类花生酸代谢紊乱是孕早期自然流产发生的风险因素。此外,胎盘蜕膜和绒毛中溶血磷脂及绒毛中甘油二酯的含量偏低也是孕早期自然流产发生的潜在风险因素。(3)动物实验发现,孕鼠PUFA的摄入对丙戊酸钠(VPA)诱导的NTD及流产的发生具有预防作用,并且n-3 PUFA的效果优于n-6 PUFA。PUFA的摄入有效减轻了 VPA引起的胎盘中类花生酸TXB2及6-keto-PGF1α的过量合成,并且n-3 PUFA的摄入降低了胎盘中TXB2/6-keto-PGF1α的比值,表明PUFA调控胎盘中类花生酸的合成是其预防NTD及流产发生的机制之一。(4)动物实验发现,孕鼠腹腔注射VPA抑制了孕鼠肝脏中叶酸-Hcy的代谢通路关键基因(DHFR、MTRR、CSE、GAMT及CBS)的mRNA和蛋白表达,。与孕鼠肝脏中的结果相反,孕鼠VPA的注射升高了胚胎中叶酸-Hcy代谢通路关键基因(DHFR、MTRR、CSE、GAMT、CBS 及 MTHFR)的 mRNA 及蛋白表达水平。孕鼠 n-3 PUFA 或 n-6 PUFA的摄入均有效减轻了 VPA所引起的孕鼠肝脏及胚胎中叶酸-Hcy代谢紊乱,并且n-3 PUFA的效果优于n-6 PUFA。这很好的阐明了 n-3 PUFA及n-6 PUFA能够降低VPA诱导的NTD及流产发病率并且n-3 PUFA的效果优于n-6 PUFA的机制。此外,孕鼠VPA的注射降低了孕鼠肝脏中C18:2n-6、C20:4n-6及C22:6n-3的含量,而n-3 PUFA及n-6 PUFA的摄入有效的弥补了 VPA所引起的孕鼠肝脏中这三种PUFA的不足,这可能也是PUFA预防NTD及流产发生的机制之一。综上所述,本论文通过人体病例对照实验发现PUFA的缺乏及类花生酸代谢异常均与NTD及自然流产的发生密切相关。动物实验发现孕鼠n-3 PUFA或n-6 PUFA的摄入均能有效预防NTD及流产的发生,并且n-3 PUFA的效果优于n-6 PUFA。动物实验表明,PUFA的摄入能够降低NTD及流产发病率主要是通过调控类花生酸代谢、叶酸-Hcy代谢及弥补机体PUFA的不足而实现。
[Abstract]:Neural tube malformation (NTD) and spontaneous abortion are the diseases that occur during embryonic development..NTD is a congenital malformation caused by the failure of the embryonic neural tube to complete normal closure. The metabolic disorder of folic acid - homocysteine Hcy caused by folic acid deficiency is the most important cause of the occurrence of NTD. In addition, the inositol metabolic pathway is abnormal, and the inflammatory reaction is It is also the cause of the occurrence of NTD. Spontaneous abortion refers to the spontaneous abortion of non human beings. The main causes include chromosomal abnormalities, infection, immunity and inflammation, endocrine dysfunction, folic acid Hcy metabolism, and so on. Polyunsaturated fatty acids (PUFA) are the important structural components of the nervous system produced by.PUFA metabolism. Arachidic acid TXA2, PGI2 (two stable metabolites are TXB2 and 6-keto-PGF1 alpha, respectively) can regulate the transfer of nutrients from the mother through the placenta to the fetus. Furthermore, PUFA also regulates the metabolic pathway and inflammatory response of folate -Hcy. Based on these results, this paper hypothesized that PUFA can be regulated by the control class. The metabolism of arachidic acid, the metabolism of folic acid -Hcy, the inflammatory response and the deficiency of PUFA in the body play a certain preventive role in the occurrence of NTD and spontaneous abortion. In this paper, the correlation between PUFA and NTD and spontaneous abortion was analyzed by a case-control experiment, and the effects of PUFA intake on the incidence of NTD and abortion in the progeny of the progeny were studied by animal experiments. The main results are as follows: (1) case control experiments have found that C18:2n-6, C18:3n-6, C20:3n-6, C18:3n-3, C20:3n-3, C20:5n-3, C22:5n-3 content is too low and C20:4n-6/C20:5n-3, the ratio of TXB2/6-keto-PGF1 A is too high to be associated with high density of the risk of fetal NTD, indicating the lack of PUFA and the metabolic disorder of arachidic acid. Disorder is the risk factor of NTD. (2) case control experiment found that the essential fatty acid C18:3n-3 in placenta and decidua in early pregnancy women, the total n-3 PUFA in decidua, the content of essential fatty acid C18:2n-6 in the villi were significantly lower than that of the healthy pregnant women, indicating that the deficiency of these PUFA was closely related to the occurrence of spontaneous abortion in early pregnancy. The ratio of C20:4n-6/C20-5n-3 in the villi of women with spontaneous abortion was significantly higher than that in healthy pregnant women, while the level of arachidic acid like arachidic acid produced by C20:4n-6 metabolism, HEPE, LTB5, TXB3, was significantly lower than that of healthy pregnant women, indicating that the metabolic disorder of arachidic acid in the placental villi was a risk factor for spontaneous abortion in the early pregnancy. In addition, the low content of lysophosphatidin in the placental decidua and villi is also a potential risk factor for spontaneous abortion in the early pregnancy. (3) animal experiments have found that the intake of PUFA in pregnant mice has a preventive effect on the occurrence of NTD and abortion induced by sodium valproate (VPA), and the effect of n-3 PUFA is better than the intake of n-6 PUFA.PUFA. The excess synthesis of arachidic acid TXB2 and 6-keto-PGF1 alpha in placenta caused by VPA was effectively reduced, and the intake of n-3 PUFA decreased the ratio of TXB2/6-keto-PGF1 alpha in the placenta. It was suggested that PUFA regulation of the synthesis of arachidic acid in placenta is one of the mechanisms to prevent NTD and abortion. (4) animal experiments found that pregnant mice injected VPA in abdominal cavity. MRNA and protein expression of key genes of metabolic pathway (DHFR, MTRR, CSE, GAMT and CBS) in the liver of pregnant rats (DHFR, MTRR, GAMT and CBS). Contrary to the results in the liver of pregnant mice, the injection of VPA in pregnant mice increased the level of the key genes of the -Hcy metabolic pathway in the embryo of the embryo. The intake of n-3 PUFA was better than n-6 PUFA., and the effect of n-3 PUFA and n-6 PUFA was better than that of n-6 PUFA.. The effect of n-3 PUFA and n-6 PUFA on VPA induced NTD and abortion was better than that of n-6 PUFA.. The content of C18:2n-6, C20:4n-6 and C22:6n-3 in the rat liver, and the intake of n-3 PUFA and n-6 PUFA effectively compensate for the deficiency of these three kinds of PUFA in the liver of pregnant mice caused by VPA, which may also be one of the mechanisms for PUFA to prevent NTD and abortion. Metabolic abnormalities are closely related to the occurrence of NTD and spontaneous abortion. Animal experiments have found that the intake of n-3 PUFA or n-6 PUFA in pregnant mice can effectively prevent the occurrence of NTD and abortion, and the effect of n-3 PUFA is superior to n-6 PUFA. animal experiments. The PUFA intake can reduce the incidence of NTD and abortion mainly through the regulation of the metabolism of arachidic acid, folic acid -Hcy metabolism and reparation of the deficiency of PUFA in the body.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：R153.1

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