Oleic acid is an abundant free fatty acid present in livestock that are in a negative energy-balance state, and it may have detrimental effects on female reproduction and fertility. Oleic acid induces lipid accumulation in bovine granulosa cells, which leads to a foam cell-like morphology and reduced steroidogenesis. However, why oleic acid increases lipid accumulation but decreases steroidogenesis remains unclear. This study focused on oleic acid’s effects on lipid type and steroidogenesis. Oleic acid increased the lipid accumulation in a concentration-dependent manner and mainly increased the triglyceride level and decreased the cholesterol ester level. Oleic acid also led to a decline in estradiol and progesterone production in porcine granulosa cells in vitro. In addition, oleic acid up-regulated the expression of CD36 and diacylglycerol acyltransferase 2, but down-regulated the expression of 3-hydroxy-3-methylglutaryl-coenzyme A reductase, scavenger receptor class B member 1 and acetyl-Coenzyme A acetyltransferase 2, as well as steroidogenesis-related genes, including cytochrome P450 family 11 subfamily A member 1, cytochrome P450 family 19 subfamily A member 1 and 3 as well as steroidogenic acute regulatory protein at the mRNA and protein levels. An oleic acid-rich diet also enhanced the triglyceride levels and reduced the cholesterol levels in ovarian tissues of female mice, which resulted in lower estradiol levels than in control-fed mice. Compared with the control, decreases in estrus days and the numbers of antral follicles and corpora lutea, as well as an increase in the numbers of the atretic follicles, were found in the oleic acid-fed female mice. Oleic acid changed the lipid type stored in lipid droplets of ovarian granulosa cells, and led to a decrease in steroidogenesis. These results improve our understanding of fertility decline in livestock that are in a negative energy-balance state.

中文翻译：

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油酸通过改变储存在卵巢颗粒细胞脂滴中的脂质类型来减少类固醇生成

油酸是一种丰富的游离脂肪酸，存在于处于负能量平衡状态的牲畜中，它可能对雌性生殖和生育能力产生不利影响。油酸诱导牛颗粒细胞中的脂质积累，从而导致泡沫细胞样形态和类固醇生成减少。然而，为什么油酸增加脂质积累但减少类固醇生成仍不清楚。这项研究的重点是油酸对脂质类型和类固醇生成的影响。油酸以浓度依赖性方式增加脂质积累，主要增加甘油三酯水平和降低胆固醇酯水平。油酸还导致体外猪颗粒细胞中雌二醇和孕酮的产生下降。此外，油酸上调 CD36 和二酰基甘油酰基转移酶 2 的表达，但下调 3-羟基-3-甲基戊二酰辅酶 A 还原酶、清道夫受体 B 类成员 1 和乙酰辅酶 A 乙酰转移酶 2 的表达，以及类固醇生成相关基因，包括细胞色素 P450 家族 11 亚家族 A 成员 1、细胞色素 P450 家族 19 亚家族 A 成员 1 和 3 以及 mRNA 和蛋白质水平的类固醇生成急性调节蛋白。富含油酸的饮食还提高了雌性小鼠卵巢组织中的甘油三酯水平并降低了胆固醇水平，从而导致雌二醇水平低于对照组小鼠。与对照相比，发情天数减少，窦卵泡和黄体数量减少，闭锁卵泡数量增加，在油酸喂养的雌性小鼠中发现。油酸改变了储存在卵巢颗粒细胞脂滴中的脂质类型，导致类固醇生成减少。这些结果提高了我们对处于负能量平衡状态的牲畜生育能力下降的理解。