人类胚胎（图）

PLoS ONE的最新一项研究报道发现，在那些极为肥胖或患有II型糖尿病的女性的卵巢中可能含有高水平的饱和脂肪酸，这会影响胚胎的发育。

来自比利时、英国和西班牙的科学家研究发现那些暴露在高水平脂肪酸的胚胎通常细胞数较少，这会影响基因的表达并改变其代谢活力，最终影响发育能力。

尽管这项研究中使用的是牛的卵细胞，但结果也可以用来解释为何肥胖或糖尿病的女性容易引起新陈代谢紊乱并难以受孕。她们会代谢较多的体内脂肪，导致卵巢中的脂肪酸含量较高，使得卵细胞难以正常发育。

该研究的负责人，比利时安特卫普大学的Jo Leroy教授说道：“我们在母牛体内诱导了类似了代谢紊乱，并导致这些动物卵细胞质量和受孕率下降。虽然在早期的研究我们就已经发现高水平脂肪酸会影响卵巢中胚胎的发育，但这是我们首次证实了其对胚胎存活率确实有负面的影响。”

该论文的研究人员，英国赫尔大学的Roger Sturmey博士说道：“我们的研究发现对妇女们是一个警示：在准备受孕时务必要保持健康的体重。”
科学家们在母牛受精后进行了8天的测试，发现胚泡周围包裹有70到100个细胞。其中胚胎活性的最关键指标是代谢活力，这通过它从周围环境中吸收和释放的物质量可以计算出来。

Sturmey博士说道：“具有活力且能成功受孕的胚胎通常会有较低水平的氨基酸代谢，而这些处在高水平脂肪酸的胚胎显示有较高水平的氨基酸代谢，且对氧气、葡萄糖和乳汁的吸收也发生了改变，所有的现象均表明其代谢失调和活力下降。”

科学家们下一步打算在临床上进行进一步的测试。

英文论文原文摘要：

Elevated Non-Esterified Fatty Acid Concentrations during Bovine Oocyte Maturation Compromise Early Embryo Physiology

Elevated concentrations of serum non-esterified fatty acids (NEFA), associated with maternal disorders such as obesity and type II diabetes, alter the ovarian follicular micro-environment and have been associated with subfertility arising from reduced oocyte developmental competence. We have asked whether elevated NEFA concentrations during oocyte maturation affect the development and physiology of zygotes formed from such oocytes, using the cow as a model. The zygotes were grown to blastocysts, which were evaluated for their quality in terms of cell number, apoptosis, expression of key genes, amino acid turnover and oxidative metabolism. Oocyte maturation under elevated NEFA concentrations resulted in blastocysts with significantly lower cell number, increased apoptotic cell ratio and altered mRNA abundance of DNMT3A, IGF2R and SLC2A1. In addition, the blastocysts displayed reduced oxygen, pyruvate and glucose consumption, up-regulated lactate consumption and higher amino acid metabolism. These data indicate that exposure of maturing oocytes to elevated NEFA concentrations has a negative impact on fertility not only through a reduction in oocyte developmental capacity but through compromised early embryo quality, viability and metabolism.