亚油酸对奶牛乳腺上皮细胞乳脂肪和乳蛋白合成相关基因表达的影响

Effect of Linoleic Acid on the Expression of Genes Associated with Milk Fat and Milk Protein Synthesis of Bovine Mammary Epithelial Cells

该文主要研究了添加不同浓度的亚油酸（顺-9,顺-12-十八碳二烯酸）（0、20、40、80、120μmol/L）对奶牛乳腺上皮细胞（bovine mammary epithelial cells,BMECs）乳脂和乳蛋白合成相关基因表达的影响。通过MTT法检测细胞活力,利用甘油三酯试剂盒检测BMECs内甘油三酯（triglyceride,TAG）的合成量,实时荧光定量PCR检测乳脂和乳蛋白合成相关基因的表达。结果表明：（1）添加20μmol/L的亚油酸能促进BMECs的增殖,120μmol/L的亚油酸组BMECs的相对增殖率显著低于对照组（P〈0.05）;（2）40μmol/L和80μmol/L亚油酸添加组BMECs中TAG的合成量显著高于对照组（P〈0.05）;（3）添加20μmol/L亚油酸显著上调αs1-酪蛋白（casein alpha s1 identifiers symbols,CSN1S1）和κ-酪蛋白（κ-casein,CSN3）基因的表达,而80μmol/L和120μmol/L亚油酸显著下调CSN1S1和CSN3基因的表达（P〈0.05）;（4）120μmol/L亚油酸上调了真核启始4E结合蛋白-1（eukaryotic initiation factor 4E-binding-protein-1,4EBP1）基因的表达,下调了核糖体蛋白S6激酶-1（ribosomal protein S6 kinase-1,RPS6K1）基因的表达（P〈0.05）;（5）添加20~120μmol/L亚油酸显著下调脂肪酸合酶（fatty acid synthase,FASN）、硬脂酰辅酶A去饱和酶（stearoyl-Co A desaturase,SCD）、脂肪酸结合蛋白-3（fatty acid-binding protein-3,FABP3）的基因表达（P〈0.05）;（6）20μmol/L亚油酸添加组过氧化物酶体增殖物激活受体（peroxisome proliferator-activated receptorγ,PPARG）基因表达量显著高于对照组,而120μmol/L亚油酸组PPARG、固醇调节元件结合因子-1（sterol regulatory element binding factor-1,SREBF1）的表达量显著低于对照组（P〈0.05）。综上所述,20~40μmol/L的亚油酸对BMECs乳脂肪和乳蛋白合成有较好的促进效果。

The aim of this study was to determine the effect of linoleic acid supplementation（0, 20, 40, 80, 120 μmol/L） on expression of genes involved in milk fat and protein synthesis in bovine mammary epithelial cells（BMECs）. Cell viability was detected by MTT. Triglyceride（TAG） content was measured by using triglyceride de-termination kit. Expression of genes involved in milk fat and milk protein synthesis were measured by RT-q PCR. The results showed as follows.（1） 20 μmol/L linoleic acid promoted the proliferation of BMECs. However, 120 μmol/L linoleic acid signif icantly decreased the relative proliferation rate of BMECs（P〈0.05）.（2） The content of TAG in BMECs were signif icantly higher in groups with addition of 40 μmol/L and 80 μmol/L linoleic acid than that of control group（P〈0.05）.（3） 20 μmol/L linoleic acid significantly upregulated the transcription of CSN1S1 and CSN3, whereas 80 μmol/L and 120 μmol/L linoleic acid signif icantly downregulated the transcription of CSN1S1 and CSN3（P〈0.05）.（4） 120 μmol/L linoleic acid signif icantly upregulated the transcription of 4EBP1, and downregulated the transcription of RPS6K1（P〈0.05）.（5） The mR NA levels of FASN, SCD and FABP3 in linoleic acid supplementation groups were significantly lower than those of control group（P〈0.05）.（6） 20 μmol/L linoleic acid significantly upregulated the transcription of PPARG, whereas 120 μmol/L linoleic acid signif icantly downregulated the transcription of PPARG and SREBF1（P〈0.05）. In conclusion, 20~40 umol/L linoleic acid are optimal, considering its simulative effects on milk fat and protein synthesis.