The Robinson Institute, School of Paediatrics & Reproductive Health, University of Adelaide, Adelaide, SA 5005, Australia.
Anim Reprod Sci. 2012 Sep;134(1-2):69-75. doi: 10.1016/j.anireprosci.2012.08.013. Epub 2012 Aug 11.
Successful embryo and fetal development is dependent on the quality of the oocyte from which it was derived. Several studies to date have demonstrated the link between appropriate metabolism and sufficient ATP production with oocyte quality and preimplantation embryo development. Metabolism of fatty acids for the purpose of synthesizing ATP occurs within mitochondria via β-oxidation and entry of fatty acids into this organelle is the rate-limiting step in this process. Transport of activated fatty acids into mitochondria is catalyzed by carnitine palmitoyl transferase-I (CPTI) which also requires the metabolite carnitine. Once inside the mitochondrial matrix, fatty acids are broken down into acetyl CoA molecules which are further metabolized via the TCA cycle and electron transport chain to produce ATP. The potential to improve oocyte quality by modulating fatty acid metabolism and β-oxidation with carnitine in culture media formulations or via dietary supplementation has received little attention. This review summarizes studies to date investigating the developmental importance of β-oxidation through the use of metabolic inhibitors and whether regulation by carnitine, in vitro or in vivo, has beneficial effects on oocyte and embryo development. Overall, there is little evidence to date that dietary carnitine can improve oocyte quality or female fertility; however inclusion of l-carnitine to in vitro oocyte maturation and embryo growth media improves embryo outcomes, most likely by supplying the oocyte and embryo with an essential co-factor required to utilize fatty acids.
胚胎和胎儿的成功发育依赖于卵母细胞的质量。迄今为止，已有多项研究表明，适当的代谢和足够的 ATP 生成与卵母细胞质量和胚胎前体发育之间存在关联。脂肪酸用于合成 ATP 的代谢发生在线粒体中，通过β-氧化，脂肪酸进入该细胞器是这个过程的限速步骤。激活的脂肪酸进入线粒体由肉碱棕榈酰转移酶-I（CPTI）催化，该酶还需要代谢物肉碱。一旦进入线粒体基质，脂肪酸就会分解成乙酰辅酶 A 分子，这些分子通过 TCA 循环和电子传递链进一步代谢，产生 ATP。通过在培养基配方中使用肉碱调节脂肪酸代谢和β-氧化，或通过饮食补充来提高卵母细胞质量的潜力，尚未得到广泛关注。这篇综述总结了迄今为止通过使用代谢抑制剂研究β-氧化对发育的重要性的研究，以及肉碱在体外或体内对卵母细胞和胚胎发育的调节是否有有益的影响。总的来说，目前几乎没有证据表明膳食肉碱可以改善卵母细胞质量或女性生育能力；然而，在体外卵母细胞成熟和胚胎生长培养基中添加左旋肉碱可以改善胚胎结局，这很可能是因为它为卵母细胞和胚胎提供了利用脂肪酸所需的必需辅助因子。
