Department of Veterinary Medicine, Università Degli Studi di Milano, 26900, Milano, Italy.
Department of Veterinary Medicine, Università Degli Studi di Milano, 26900, Milano, Italy.
J Dairy Sci. 2020 Sep;103(9):8554-8563. doi: 10.3168/jds.2020-18659. Epub 2020 Jul 16.
The conjugated linoleic acid (CLA) isomers, a group of naturally occurring isomers of the essential fatty acid (FA) linoleic acid, have received special attention in animal and human nutrition. Although they have long been used as dietary integrators in dairy cows, the effects of CLA isomers on bovine immune cells remain mostly undisclosed. The present study aimed to cover this gap and investigate the in vitro effects of CLA on inflammatory functions, including chemotaxis, phagocytosis, killing capability, and extracellular respiratory burst of purified bovine monocytes (CD14). The apoptosis rate of monocytes was addressed as well. Once assessed, the effects of different concentrations (10, 50, 100, and 500 μM) of the 2 main CLA isomers, namely cis-9,trans-11 and trans-10,cis-12, the experiments were carried out using a concentration of 50 μM of the CLA isomers, both individually and in a mixture (50:50). The immunomodulatory activities of linoleic acid, an essential FA, and stearic acid, a saturated FA, were also investigated. Only the 50:50 CLA mixture was able to reduce monocyte apoptosis and to increase the extracellular respiratory burst during experimental proinflammatory conditions, as assessed by measuring production of reactive oxygen species. Linoleic acid and CLA had no effects on chemotaxis, phagocytosis, or killing capability. Remarkably, treatment of monocytes with stearic acid significantly reduced their chemotactic capability. The present results demonstrated that CLA isomers do have immunomodulatory effects on some functions of bovine monocytes, and that the mixture of the 2 CLA isomers is more effective than the CLA isomers individually.
共轭亚油酸（CLA）异构体是必需脂肪酸（FA）亚油酸的一组天然异构体，在动物和人类营养中受到特别关注。尽管它们长期以来一直被用作奶牛的膳食调节剂，但 CLA 异构体对牛免疫细胞的影响在很大程度上仍未被揭示。本研究旨在填补这一空白，并研究 CLA 对炎症功能（包括趋化性、吞噬作用、杀伤能力和纯化牛单核细胞（CD14）的细胞外呼吸爆发）的体外影响。还研究了单核细胞的凋亡率。一旦评估，研究了不同浓度（10、50、100 和 500 μM）的 2 种主要 CLA 异构体，即顺式-9，反式-11 和反式-10，顺式-12，使用 50 μM 的 CLA 异构体浓度进行实验，单独使用和混合使用（50:50）。还研究了必需脂肪酸亚油酸和饱和脂肪酸硬脂酸的免疫调节活性。只有 50:50 的 CLA 混合物能够减少单核细胞凋亡，并在实验性促炎条件下增加细胞外呼吸爆发，如通过测量活性氧的产生来评估。亚油酸和 CLA 对趋化性、吞噬作用或杀伤能力没有影响。值得注意的是，用硬脂酸处理单核细胞会显著降低其趋化能力。本研究结果表明，CLA 异构体确实对牛单核细胞的某些功能具有免疫调节作用，并且 2 种 CLA 异构体的混合物比单独的 CLA 异构体更有效。
