Moore K, Kramer J M, Rodriguez-Sallaberry C J, Yelich J V, Drost M
Department of Animal Sciences, Institute of Food and Agriculture Sciences, University of Florida, Gainesville, FL 32611-0910, USA.
Theriogenology. 2007 Sep 15;68(5):717-27. doi: 10.1016/j.theriogenology.2007.06.001. Epub 2007 Jul 12.
Embryos produced through somatic cell nuclear transfer (NT) or in vitro production (IVP) are often associated with increased abortion and abnormalities thought to arise from disruptions in normal gene expression. The insulin-like growth factor (IGF) family has a major influence on embryonic, fetal and placental development; differences in IGF expression in NT- and IVP-derived embryos may account for embryonic losses during placental attachment. In the present study, expression of IGF-I, IGF-II, IGF-I receptor (IGF-IR), and IGF-IIR mRNAs was quantitated in Day 7 and 25 bovine embryos produced in vivo, by NT, IVP, or parthenogenesis, to further understand divergent changes occurring during development. Expression of the IGF-I gene was not detected in Day 7 blastocysts for any treatment. However, there were no differences (P>0.10) among Day 7 treatments in the amounts of IGF-IR, IGF-II, and IGF-IIR mRNA. For Day 25 conceptuses, there was higher expression of IGF-I mRNA for NT and IVP embryonic tissues than for in vivo embryonic tissues (P<0.05). Furthermore, embryonic tissues from NT-derived embryos had higher expression of IGF-II mRNA than IVP embryonic tissues (P<0.05). Placental expression of IGF-IIR mRNA was greater for NT-derived than in vivo-derived embryos (P<0.05). There were no differences in IGF-IR mRNA across all treatments and tissues (P>0.10). In conclusion, these differences in growth factor gene expression during early placental attachment and rapid embryonic growth may directly or indirectly contribute to increased losses and abnormalities in IVP- and NT-derived embryos.
通过体细胞核移植（NT）或体外生产（IVP）产生的胚胎通常与流产增加和异常情况相关，这些异常被认为是由正常基因表达的破坏引起的。胰岛素样生长因子（IGF）家族对胚胎、胎儿和胎盘发育有重大影响；NT和IVP来源胚胎中IGF表达的差异可能是胎盘附着期间胚胎损失的原因。在本研究中，对体内、通过NT、IVP或孤雌生殖产生的第7天和第25天牛胚胎中IGF-I、IGF-II、IGF-I受体（IGF-IR）和IGF-IIR mRNA的表达进行了定量，以进一步了解发育过程中发生的不同变化。任何处理的第7天囊胚中均未检测到IGF-I基因的表达。然而，第7天的处理之间，IGF-IR、IGF-II和IGF-IIR mRNA的量没有差异（P>0.10）。对于第25天的孕体，NT和IVP胚胎组织中IGF-I mRNA的表达高于体内胚胎组织（P<0.05）。此外，NT来源胚胎的胚胎组织中IGF-II mRNA的表达高于IVP胚胎组织（P<0.05）。NT来源胚胎的胎盘IGF-IIR mRNA表达高于体内来源胚胎（P<0.05）。所有处理和组织的IGF-IR mRNA均无差异（P>0.10）。总之，早期胎盘附着和胚胎快速生长期间生长因子基因表达的这些差异可能直接或间接导致IVP和NT来源胚胎的损失增加和异常。
