Lowe Jenna L, Bathgate Roslyn, Grupen Christopher G
Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, 425 Werombi Road, Camden, NSW 2570, Australia.
Reprod Fertil Dev. 2019 Mar;31(3):557-569. doi: 10.1071/RD18043.
Porcine oocytes contain a large amount of endogenous lipid, which is thought to function as an intracellular source of energy. The aim of this study was to determine the effects of stimulating or inhibiting lipid metabolism using l-carnitine or etomoxir respectively on the IVM of porcine oocytes cultured in media of varying carbohydrate composition. In the presence of pyruvate and lactate, exclusion of glucose inhibited oocyte nuclear and cytoplasmic maturation compared with oocytes matured in media containing low (1.5mM) and high (4.0mM) concentrations of glucose. In the absence of pyruvate and lactate in low-glucose medium only, a greater proportion of l-carnitine-treated oocytes progressed to the MII stage compared with untreated oocytes. The inclusion of pyruvate and lactate significantly altered the distribution of cytoplasmic lipid droplets and elevated the ATP content of oocytes, whereas the l-carnitine treatment did not. Further, the inhibitory effect of etomoxir on nuclear maturation was decreased in high- compared with low-glucose medium. The results indicate that carbohydrate substrates are absolutely necessary for effective porcine oocyte maturation, and that l-carnitine supplementation can only partially compensate for deficiencies in carbohydrate provision.
猪卵母细胞含有大量内源性脂质，被认为可作为细胞内的能量来源。本研究的目的是分别使用左旋肉碱或依托莫西抑制或刺激脂质代谢，以研究其对在不同碳水化合物组成培养基中培养的猪卵母细胞体外成熟（IVM）的影响。在丙酮酸和乳酸存在的情况下，与在含有低浓度（1.5mM）和高浓度（4.0mM）葡萄糖的培养基中成熟的卵母细胞相比，不含葡萄糖会抑制卵母细胞核和细胞质的成熟。仅在低葡萄糖培养基中不存在丙酮酸和乳酸的情况下，与未处理的卵母细胞相比，更大比例的经左旋肉碱处理的卵母细胞发育到MII期。添加丙酮酸和乳酸显著改变了细胞质脂质滴的分布，并提高了卵母细胞的ATP含量，而左旋肉碱处理则没有。此外，与低葡萄糖培养基相比，依托莫西对高葡萄糖培养基中核成熟的抑制作用减弱。结果表明，碳水化合物底物对于猪卵母细胞的有效成熟是绝对必要的，并且补充左旋肉碱只能部分弥补碳水化合物供应的不足。
