Department of Animal Sciences, Center for Nutrition and Pregnancy, North Dakota State University, Fargo, North Dakota 58108, USA.
Reproduction. 2011 Apr;141(4):529-40. doi: 10.1530/REP-10-0505. Epub 2011 Jan 27.
To characterize early fetal placental development, gravid uterine tissues were collected from pregnant ewes every other day from day 16 to 30 after mating. Determination of 1) cell proliferation was based on Ki67 protein immunodetection; 2) global methylation was based on 5-methyl-cytosine (5mC) expression and mRNA expression for DNA methyltransferases (DNMTs) 1, 3a, and 3b; and 3) vascular development was based on smooth muscle cell actin immunolocalization and on mRNA expression of several factors involved in the regulation of angiogenesis in fetal membranes (FMs). Throughout early pregnancy, the labeling index (proportion of proliferating cells) was very high (21%) and did not change. Expression of 5mC and mRNA for DNMT3b decreased, but mRNA for DNMT1 and 3a increased. Blood vessels were detected in FM on days 18-30 of pregnancy, and their number per tissue area did not change. The patterns of mRNA expression for placental growth factor, vascular endothelial growth factor, and their receptors FLT1 and KDR; angiopoietins 1 and 2 and their receptor TEK; endothelial nitric oxide synthase and the NO receptor GUCY13B; and hypoxia inducing factor 1 α changed in FM during early pregnancy. These data demonstrate high cellular proliferation rates, and changes in global methylation and mRNA expression of factors involved in the regulation of DNA methylation and angiogenesis in FM during early pregnancy. This description of cellular and molecular changes in FM during early pregnancy will provide the foundation for determining the basis of altered placental development in pregnancies compromised by environmental, genetic, or other factors.
为了描述早期胎儿胎盘的发育情况，每隔一天从配种后第 16 天到第 30 天收集怀孕母羊的妊娠子宫组织。通过以下方法确定 1）细胞增殖：基于 Ki67 蛋白免疫检测；2）整体甲基化：基于 5-甲基胞嘧啶（5mC）表达和 DNA 甲基转移酶（DNMTs）1、3a 和 3b 的 mRNA 表达；3）血管发育：基于平滑肌细胞肌动蛋白免疫定位和胎儿膜（FM）中参与血管生成调节的几个因子的 mRNA 表达。在整个早孕期间，标记指数（增殖细胞的比例）非常高（21%）且没有变化。5mC 的表达和 DNMT3b 的 mRNA 减少，但 DNMT1 和 3a 的 mRNA 增加。在妊娠第 18-30 天检测到 FM 中的血管，其在组织面积中的数量没有变化。胎盘生长因子、血管内皮生长因子及其受体 FLT1 和 KDR；血管生成素 1 和 2 及其受体 TEK；内皮型一氧化氮合酶和 NO 受体 GUCY13B；以及缺氧诱导因子 1α 在 FM 中的 mRNA 表达模式在早孕期间发生了变化。这些数据表明，在 FM 中，细胞增殖率高，整体甲基化和参与 DNA 甲基化和血管生成调节的因子的 mRNA 表达发生变化。这些关于 FM 在早孕期间的细胞和分子变化的描述将为确定因环境、遗传或其他因素而受损的妊娠中胎盘发育改变的基础提供依据。
