Li Tingting, Bai Hui, Yang Liang, Wang Hongzhuang, Wei Shengjuan, Yan Peishi
College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, PR China.
College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, PR China.
J Therm Biol. 2023 Feb;112:103446. doi: 10.1016/j.jtherbio.2022.103446. Epub 2022 Dec 27.
White adipocytes can be transformed into beige adipocytes through the process of browning under cold exposure. To investigate the effects and underlying mechanisms of cold exposure on subcutaneous white fat in cattle, in vitro and in vivo studies were performed. Eight bulls of Jinjiang cattle breed (Bos taurus) aged 18 months were allocated to the control group (n = 4, autumn) or the cold group (n = 4, winter) by different slaughter seasons. Biochemical and histomorphological parameters were detected in blood and backfat samples. Subcutaneous adipocytes from Simental cattle (Bos taurus) were then isolated and cultured at a normal body temperature (37 °C) and at a cold temperature (31 °C) in vitro. In the in vivo study, cold exposure stimulated subcutaneous white adipose tissue (sWAT) browning by reducing adipocyte sizes and up-regulating the expression levels of browning-specific makers (UCP1, PRDM16, and PGC-1α) in cattle. In addition, cold-exposed cattle displayed lower lipogenesis transcriptional regulator levels (PPARγ and CEBPα) and higher lipolysis regulator levels (HSL) in sWAT. In the in vitro study, cold temperature inhibited subcutaneous white adipocytes (sWA) adipogenic differentiation by reducing lipid contents and decreasing the expression of adipogenic marker genes and proteins. Furthermore, cold temperature led to sWA browning which was characterized by increased browning-related genes, mitochondrial contents, and mitochondrial biogenesis-specific markers. In addition, p38 MAPK signaling pathway activity was stimulated by the incubation in cold temperature for 6 h in sWA. We concluded that the cold-induced browning of the subcutaneous white fat was beneficial to the production of heat and the maintenance of body temperature regulation in cattle.
在寒冷暴露的情况下，白色脂肪细胞可通过褐变过程转化为米色脂肪细胞。为了研究寒冷暴露对牛皮下白色脂肪的影响及其潜在机制，进行了体外和体内研究。选取8头18月龄的晋江牛（Bos taurus）公牛，根据不同的屠宰季节分为对照组（n = 4，秋季）和寒冷组（n = 4，冬季）。检测血液和背部脂肪样本中的生化和组织形态学参数。然后分离西门塔尔牛（Bos taurus）的皮下脂肪细胞，在正常体温（37°C）和低温（31°C）下进行体外培养。在体内研究中，寒冷暴露通过减小牛脂肪细胞大小并上调褐色脂肪特异性标志物（UCP1、PRDM16和PGC-1α）的表达水平，刺激皮下白色脂肪组织（sWAT）褐变。此外，寒冷暴露的牛sWAT中脂肪生成转录调节因子水平（PPARγ和CEBPα）较低，脂肪分解调节因子水平（HSL）较高。在体外研究中，低温通过降低脂质含量以及减少脂肪生成标志物基因和蛋白质的表达，抑制皮下白色脂肪细胞（sWA）的成脂分化。此外，低温导致sWA褐变，其特征是与褐变相关的基因、线粒体含量和线粒体生物发生特异性标志物增加。另外，在低温下培养6小时可刺激sWA中p38 MAPK信号通路的活性。我们得出结论，寒冷诱导的皮下白色脂肪褐变有利于牛产热和维持体温调节。
