【作者】 张娟；

【导师】 吴信；

【作者基本信息】 南昌大学 ， 营养与食品卫生学， 2020， 硕士

【摘要】 肥胖已经成为世界性重要公共卫生问题之一,对早期生命而言,母体孕期营养过剩是造成其肥胖的主要原因之一。研究表明,尿苷可以调控肝脏中脂质代谢,缓解高脂饮食引起的肥胖。但是尿苷是否会通过母鼠影响子代的脂代谢还不清楚。因此,本研究的目的是通过在母鼠妊娠期和哺乳期高脂饮食下补充尿苷来研究尿苷对高脂饮食母鼠和子鼠脂代谢的影响和机理。本研究选择8周龄雌鼠和雄鼠按2:1进行配种。将45只怀孕7天的母鼠随机均匀地分为三组(每组15只),分别为对照组,高脂组和高脂补充尿苷组(尿苷添加量为400mg/kg体重/d)。母鼠分娩后,采集新生子鼠肝脏,21天新生子鼠断奶后,采集断奶子鼠血清和肝脏,母鼠血清和肝脏组织。最后对所有样品进行实验室分析。主要研究结果如下:(1)高脂日粮可增加母鼠的体重和肠系膜脂系数,提高母鼠血清GLU,TG,TC,HDL和LDL的含量,显著降低母鼠肝脏中Lxrβ,Cyp27a1,Fxr和Shp基因的表达量(P<0.05)。补充尿苷可以降低母鼠肠系膜脂系数、提高母鼠皮下脂系数,降低血清中TG,TC,HDL,LDL和TBA的含量,显著降低了母鼠肝脏中Acc和Fat/cd36的表达水平(P<0.05)。(2)母鼠妊娠中后期饲喂高脂日粮会降低新生子鼠的数量,增加新生子鼠的体重。此外,妊娠期高脂饮食显著降低了 ICR新生子鼠肝脏Fat/cd36基因的表达量,显著上调了Cyp2 7a1基因的表达量(P<0.05)。但是补充尿苷显著增加了Fat/cd36的表达,显著下调了Hmgcr,Lxrβ和Cyp27a1的表达量(P<0.05)。(3)高脂饮食显著提高了断奶子鼠的体重(P<0.05)。高脂饮食显著增加了断奶雄鼠血清中GLU的含量,显著降低了断奶雄鼠血清中总胆汁酸的含量。断奶雌鼠肝脏基因表达结果显示,高脂显著的降低了肝脏中Fasn,Acc,Cyp7a1,Shp的表达,显著提高了Cptla,Cyp27a1和Cyp8b1的表达(P<0.05);高脂饮食状态下补充尿苷显著降低了Cpt1a,Cp27a1和Cyp8b1的表达水平,显著上调了Cyp7a1的表达量(P<0.05)。断奶雄鼠肝脏基因表达结果发现,高脂显著降低了Fasn,Acc,Hmgcr和Shp的表达,显著上调了Cyp8b1的表达(P<0.05),补充尿苷则显著降低了Ppara,Hmgcr和Cyp8b1的表达水平(P<0.05)。(4)母鼠妊娠期高脂饮食下补充尿苷显著改变了母鼠肝脏193个基因的表达,其中显著降低了 58个基因的表达水平,显著上调了 135个基因的表达量。尿苷主要影响了 Toll样受体信号通路和产生IgA的肠道免疫网络信号通路,同时还影响了嘧啶代谢、戊糖和葡萄糖醛酸酯相互转化的信号通路。(5)高通量测序结果表明与高脂组相比,母鼠妊娠期高脂饮食下补充尿苷显著改变了新生子鼠肝脏243个基因的表达水平,其中上调了 132个基因,下调了 111个基因。尿苷主要影响了亚油酸和花生四烯酸的代谢、视黄醇和胆固醇的代谢以及固醇类激素生物合成的信号通路。更多还原

【Abstract】 Obesity has become one of the most rigorous public health problems in the world,and for newborn life,maternal overnutrition during pregnancy is one of the main reasons for its obesity.The content of nucleotides in milk is very high,of which uridine monophosphate accounts for the highest proportion,and uridine is the precursor of uridine monophosphate.Accumulated studies have shown that uridine can regulate lipid metabolism in the liver and alleviate obesity caused by high fat diet.However,it is unclear whether uridine will affect the lipid metabolism of the offspring mice through the maternal mice.Therefore,the purpose of this study was to study the effects and mechanism of uridine supplementation on lipid metabolism in maternal and the offspring mice under high-fat diet during pregnancy and lactation.In this study,8-week-old female and male mice were bred after 2 weeks of adaptation and according to the ratio of 2:1.Forty-five mice pregnant 7-days were randomly divided into three groups(n=15),a control group,a high-fat group,and a high-fat uridine supplemented group(uridine supplemented with 400 mg/kg body weight/d),respectively.After the maternal mice were delivered,the liver of the neonatal mice was collected,and after 21 days of weaning,the serum and liver of the weaned mice and the serum and liver tissue of the maternal mice were collected.Finally analyzed all samples in the laboratory.The main results are as follows:(1)The results of maternal mice showed that high-fat diet increased the body weight and mesenteric fat coefficient of the ICR maternal mice,increased the levels of GLU,TG,TC,HDL and LDL in the serum,and significantly reduced the expression of Lxrβ,Cyp27a1,Fxr and Shp in the liver(P<0.05).Uridine supplementation reduced the mesenteric fat coefficient of the maternal mice,increases the subcutaneous fat coefficient,reduces the content of TG,TC,HDL,LDL and TBA in the serum,and significantly reduces the relative expression of Acc and Fat/cd36 in the liver of maternal mice(P<0.05).(2)Results of neonatal mice showed that the feeding of high-fat diets during pregnancy reduced the number of newborn mice and increased their weight.In addition,high fat diet significantly reduced the expression of Fat/cd36 in the liver of ICR newborn mice,and significantly increased the expression of Cyp27a1(P<0.05);while uridine supplementation significantly increased the expression of Fat/cd36 and significantly reduced the expression of Hmgcr,Lxrβ and Cyp27a1 in the liver of neonatal mice(P<0.05).(3)Results of weaned mice showed that high-fat diet during pregnancy and lactation significantly increased the body weight of weaned mice(P<0.05).A high-fat diet significantly increased the content of glucose in the serum of weaned-male mice and significantly reduced the content of total bile acids in the serum of weaned-male mice(P<0.05).The results of liver gene expression in weaned-female mice showed that high fat significantly reduced the expression of Fasn,Acc,Cyp7a1 and Shp in the liver,and significantly increased the expression of Cpt1a,Cyp27a1 and Cyp8b1(P<0.05);urine supplementation under high-fat diet significantly down-regulated the expression levels of Cpt1a,Cyp27a1 and Cyp8b1,and significantly up-regulated the expression level of Cyp7a1(P<0.05).The results of liver gene expression in weaned-male mice showed that high fat significantly reduced the expression of Fasn,Acc,Hmgcr and Shp,and significantly increased the expression of Cyp8b1(P<0.05).High fat diet and supplemented with uridine significantly decreased the expression of Pparα,Hmgcr and Cyp8b1(P<0.05).(4)RNA sequencing results showed that uridine supplementation significantly changed the expression of 193 genes in the liver of maternal mice,and increased the expression of 135 genes and down-regulated the expression of 58 genes.Uridine has effect on Toll-like receptor signaling pathway and intestinal immune network for IgA production signaling pathway,besides,uridine administration also has influences on the signaling pathways of pyrimidine metabolism and the conversion of pentose and glucuronate.(5)RNA sequencing results showed that uridine supplementation significantly changed the expression of 243 genes in the liver of neonatal mice.Uridine supplementation increased 132 genes and down-regulated 111 genes.The pathways involved in these genes are the metabolism of linoleic acid and arachidonic acid,the metabolism of retinol and cholesterol,and the biosynthesis of steroid hormones.更多还原