A high-fat diet increases body fat mass and up-regulates expression of genes related to adipogenesis and inflammation in a genetically lean pig

高脂膳食促进瘦肉型猪的脂肪沉积及上调与脂肪生成和脂肪炎症相关基因的表达（英文）

Because of their physiological similarity to humans, pigs provide an excellent model for the study of obesity. This study evaluated diet-induced adiposity in genetically lean pigs and found that body weight and energy intake did not differ between controls and pigs fed the high-fat （HF） diet for three months. However, fat mass percentage, adi- pocyte size, concentrations of total cholesterol （TC）, triglyceride （TG）, high-density lipoprotein cholesterol （HDL-C） and low-density lipoprotein cholesterol （LDL-C）, insulin, and leptin in plasma were significantly higher in HF pigs than in controls. The HF diet increased the expression in backfat tissue of genes responsible for cholesterol synthesis such as Insig-1 and Insig-2. Lipid metabolism-related genes including sterol regulatory element binding protein lc （SREBP-lc）, fatty acid synthase 1 （FASN1）, diacylglycerol O-acyltransferase 2 （DGAT2）, and fatty acid binding protein 4 （FABP4） were significantly up-regulated in backfat tissue, while the expression of proliferator-activated receptor-α（PPAR-α） and carnitine palmitoyl transferase 2 （CPT2）, both involved in fatty acid oxidation, was reduced. In liver tissue, HF feeding significantly elevated the expression of SREBP-lc, FASN1, DGAT2, and hepatocyte nuclear factor-4α （HNF-4α） mRNAs. Microarray analysis further showed that the HF diet had a significant effect on the expression of 576 genes. Among these, 108 genes were related to 21 pathways, with 20 genes involved in adiposity deposition and 26 related to immune response. Our results suggest that an HF diet can induce genetically lean pigs into obesity with body fat mass expansion and adipose-related inflammation.

目的:研究高脂膳食是否会引起瘦肉型猪肥胖。创新点:发现给瘦肉型猪饲喂高脂膳食,会引起其脂肪沉积,同时导致肥胖及脂肪炎症。方法:采用化学组织切片技术测量脂肪细胞和肌肉细胞的直径、体积及密度;基因芯片检测瘦肉型杜长大猪脂肪组织相关基因的变化;荧光定量聚合酶链反应(qP CR)技术检测脂肪和肝脏组织中Insig-1、Insig-2、HMGCR、SREBP-1c、HNF-4α、FASN1、DGAT1、DGAT2、FABP4、CPT1、CPT2、PPAR-γ及PPAR-α等基因表达水平;采用血浆生化指标仪试剂盒检测猪血浆中甘油三酯、葡萄糖、总胆固醇、高密度脂蛋白胆固醇、低密度蛋白胆固醇、胰岛素及瘦素的含量。结论:结果表明,高脂膳食增加瘦肉型猪的脂肪质量,增大脂肪细胞,而且增加血浆中总胆固醇、甘油三酯、高密度脂蛋白胆固醇、低密度脂蛋白胆固醇、胰岛素和瘦素的含量。高脂膳食增加背部脂肪组织中Insig-1、Insig-2、SREBP-1c、FASN1、DGAT2和FABP4等正调节脂肪生成的基因表达量,但下调PPAR-α和CPT2的表达。在肝脏组织中,高脂膳食上调SREBP-1c、FASN1、DGAT2和HNF-4α基因表达。此外,基因芯片分析的结果发现高脂膳食上调了脂肪组织中576个基因的表达水平,其中20个基因涉及到脂肪生成,26个基因与脂肪炎症相关。综上所述,高脂膳食可以引起瘦肉型猪的脂肪沉积并导致肥胖且伴随脂肪炎症。