Aston Laboratory for Mass Spectrometry Laboratory, Chemistry Department, Purdue University, 560 Oval Drive, West Lafayette, IN 47907-2084, USA.
Anal Bioanal Chem. 2012 Dec;404(10):2915-26. doi: 10.1007/s00216-012-6426-4. Epub 2012 Oct 4.
Knowledge of the lipids present in individual preimplantation embryos is of interest in fundamental studies of embryology, in attempts to understand cellular pluripotency and in optimization of in vitro culture conditions necessary for the application and development of biotechnologies such as in vitro fertilization and transgenesis. In this work, the profiles of fatty acids and phospholipids (PL) in individual mouse preimplantation embryos and oocytes were acquired using an analytical strategy based on desorption electrospray ionization mass spectrometry (DESI-MS). The methodology avoids sample preparation and provides information on the lipids present in these microscopic structures. Differences in the lipid profiles observed for unfertilized oocytes, two- and four-cell embryos, and blastocysts were characterized. For a representative set of embryos (N = 114) using multivariate analysis (specifically principal component analysis) unfertilized oocytes showed a narrower range of PL species than did blastocysts. Two- and four-cell embryos showed a wide range of PLs compared with unfertilized oocytes and high abundances of fatty acids, indicating pronounced synthetic activity. The data suggest that the lipid changes observed in mouse preimplantation development reflect acquisition of a degree of cellular membrane functional and structural specialization by the blastocyst stage. It is also noteworthy that embryos cultured in vitro from the two-cell through the blastocyst stage have a more homogeneous lipid profile as compared with their in vivo-derived counterparts, which is ascribed to the restricted diversity of nutrients present in synthetic culture media. The DESI-MS data are interpreted from lipid biochemistry and previous reports on gene expression of diverse lipids known to be vital to early embryonic development.
个体植入前胚胎中脂质的知识在胚胎学的基础研究、试图理解细胞多能性以及优化体外培养条件方面具有重要意义，这些条件是体外受精和转基因等生物技术应用和发展所必需的。在这项工作中，使用基于解吸电喷雾电离质谱（DESI-MS）的分析策略获得了个体小鼠植入前胚胎和卵母细胞中脂肪酸和磷脂（PL）的图谱。该方法避免了样品制备，并提供了这些微观结构中存在的脂质信息。对未受精的卵母细胞、二细胞和四细胞胚胎以及囊胚的脂质图谱进行了差异特征分析。使用多元分析（特别是主成分分析）对一组代表性胚胎（N = 114）进行分析，未受精的卵母细胞显示出比囊胚更窄的 PL 种类范围。与未受精的卵母细胞相比，二细胞和四细胞胚胎显示出广泛的 PL 范围和大量的脂肪酸，表明明显的合成活性。数据表明，在小鼠植入前发育过程中观察到的脂质变化反映了囊胚阶段细胞膜功能和结构特化程度的获得。值得注意的是，与体内衍生的胚胎相比，从二细胞到囊胚阶段在体外培养的胚胎具有更均匀的脂质图谱，这归因于合成培养基中存在的营养物质多样性有限。DESI-MS 数据是从脂质生物化学和先前关于对早期胚胎发育至关重要的不同脂质的基因表达报告中进行解释的。
