Friedauer K, Dänicke S, Schulz K, Sauerwein H, Häussler S
Physiology and Hygiene Group, Institute of Animal Science, University of Bonn, Bonn, Germany.
Institute of Animal Nutrition, Friedrich-Loeffler-Institute (FLI), Federal Research Institute for Animal Health, Braunschweig, Germany.
J Anim Physiol Anim Nutr (Berl). 2015 Oct;99(5):950-61. doi: 10.1111/jpn.12268. Epub 2014 Oct 29.
Early lactating cows mobilize adipose tissue (AT) to provide energy for milk yield and maintenance and are susceptible to metabolic disorders and impaired immune response. Conjugated linoleic acids (CLA), mainly the trans-10, cis-12 isomer, reduce milk fat synthesis and may attenuate negative energy balance. Circulating glucocorticoids (GC) are increased during parturition in dairy cows and mediate differentiating and anti-inflammatory effects via glucocorticoid (GR) and mineralocorticoid receptors (MR) in the presence of the enzyme 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1). Activated GC are the main ligands for both receptors in AT; therefore, we hypothesized that tissue-specific GC metabolism is effected by varying amounts of GR, MR and 11βHSD1 and/or their localization within AT depots. Furthermore, the lipolytic and antilipogenic effects of CLA might influence the GC/GR/MR system in AT. Therefore, we aimed to localize GR and MR as well as the expression pattern and activity of 11βHSD1 in different AT depots during early lactation in dairy cows and to identify potential effects of CLA. Primiparous German Holstein cows were divided into a control (CON) and a CLA group. From day 1 post-partum (p.p.) until sample collection, the CLA group was fed with 100 g/d CLA (contains 10 g each of the cis-9, trans-11 and the trans-10, cis-12-CLA isomers). CON cows (n = 5 each) were slaughtered on day 1, 42 and 105 p.p., while CLA cows (n = 5 each) were slaughtered on day 42 and 105 p.p. Subcutaneous fat from tailhead, withers and sternum, and visceral fat from omental, mesenteric and retroperitoneal depots were sampled. The localization of GR and 11βHSD1 in mature adipocytes - being already differentiated - indicates that GC promote other effects via GR than differentiation. Moreover, MR were observed in the stromal vascular cell fraction and positively related to the pre-adipocyte marker Pref-1. However, only marginal CLA effects were observed in this study.
初产奶牛会动员脂肪组织（AT）来为产奶和维持身体机能提供能量，并且容易出现代谢紊乱和免疫反应受损的情况。共轭亚油酸（CLA），主要是反式-10，顺式-12异构体，会减少乳脂合成，并可能减轻负能量平衡。在奶牛分娩期间，循环糖皮质激素（GC）会增加，并在11β-羟基类固醇脱氢酶1型（11βHSD1）存在的情况下，通过糖皮质激素（GR）和盐皮质激素受体（MR）介导分化和抗炎作用。活化的GC是AT中这两种受体的主要配体；因此，我们假设组织特异性GC代谢受不同数量的GR、MR和11βHSD1及其在AT库中的定位影响。此外，CLA的脂解和抗脂肪生成作用可能会影响AT中的GC/GR/MR系统。因此，我们旨在确定奶牛泌乳早期不同AT库中GR和MR的定位以及11βHSD1的表达模式和活性，并确定CLA的潜在影响。初产德国荷斯坦奶牛被分为对照组（CON）和CLA组。从产后第1天（p.p.）到样本采集，CLA组每天饲喂100 g CLA（含有10 g顺式-9，反式-11和反式-10，顺式-12-CLA异构体各10 g）。CON组奶牛（每组n = 5）在产后第1天、42天和105天屠宰，而CLA组奶牛（每组n = 5）在产后第42天和105天屠宰。采集尾根、肩胛和胸骨处的皮下脂肪，以及网膜、肠系膜和腹膜后库的内脏脂肪。GR和11βHSD1在已经分化的成熟脂肪细胞中的定位表明，GC通过GR促进的作用不仅仅是分化。此外，在基质血管细胞部分观察到了MR，并且与前脂肪细胞标志物Pref-1呈正相关。然而，在本研究中仅观察到了CLA的边缘效应。
