Chemerin调控牛肌内成熟脂肪细胞脂解的作用机制

Lipolysis mechanism of Chemerin in bovine intramuscular mature adipocytes

[目的]本试验旨在分析脂肪自分泌因子Chemerin在牛肌内成熟脂肪细胞脂解中的作用及调控机制。[方法]体外培养牛肌内成熟脂肪细胞,采用油红O染色与抽提法检测成熟脂肪细胞脂解过程中脂肪含量变化,通过比色法测定细胞中甘油及游离脂肪酸的释放量;采用RT-q PCR及Western blot技术分析脂解关键基因PPARα、LPL与HSL mRNA及蛋白的表达情况。[结果]在牛肌内成熟脂肪细胞脂解过程中,细胞中Chemerin及其受体CMKLR1 mRNA表达量显著降低(P<0.05);Chemerin处理牛肌内成熟脂肪细胞后,细胞内脂肪含量减少,成熟脂肪细胞快速脂解为去分化的前体脂肪细胞,细胞中甘油和游离脂肪酸的释放量增加。脂解关键基因PPARα、LPL与HSL mRNA及蛋白表达水平与对照组相比极显著升高(P<0.01)。[结论]Chemerin通过上调脂肪细胞脂解关键基因表达,促进了牛肌内成熟脂肪细胞中脂肪的分解,进而可降低肌内脂肪含量。

[ Objectives] The aim of this study is to investigate effects and molecular mechamisms of Chemerin in the lipolysis of bovine intramuscular mature adipocytes. [ Methods] Bovine intramuscular mature adipocytes were cultured and treated by Chemerin in vitro, and fat content and cell morphological change of the mature adipocyte in the process of lipolysis were measured by oil red 0 staining. The release of glycerol and fl＇ee fatty acids was measured by colorimetry, and mRNA and protein expression of key lipolytic genes such as peroxisome proliferator-activated receptor c~ （ PPARa ）, lipopmteiu lipase （LPL） and hormone-sensitive lipase （HSL） were measured by real-time quantitative PCR（RT-qPCR）and Western blot. [ Results] mRNA expression of Chemerin and CMKLR1 were significantly decreased in the process of lipolysis （P〈 0.05 ）. Moreover, in the Chemerin-treatment group, there are less lipid droplets in cells, and the fat in mature adipocytes was accelerated to decompose into glycerol and fatty acid. Mature adipocytes de-differentiate into fibroblast-like pre-adipocytes faster than in control cells. In addition,mRNA and protein expression of PPARa, LPL and HSL were significantly up-regulated by Chemerin during mature adipocytes steatolysis compared to control group（ P〈0.01 ）. [ Conclusions ] Through up-regulation the expression of key lipolysis genes, Chemerin promoted the decomposition of fat in bovine intramuscular mature adipocytes, which can reduce the content of intramuscular fat.