本研究以体外培养的奶牛乳腺上皮细胞为模型，研究外源添加不同浓度游离α-亚麻酸（LNA）对细胞脂肪酸代谢相关靶基因mRNA转录水平的影响。体外培养的奶牛乳腺上皮细胞，以牛血清白蛋白（BSA）代替胎牛血清为对照组，BSA与不同浓度LNA为试验组，试验培养36 h，采用RT-qPCT对目的基因进行定量，检测其表达丰度。结果显示：1）0.625～5.000 μmol/L LNA极显著上调了脂肪酸转运基因中CD36的表达（P<0.01），而较高浓度（≥5 μmol/L）的LNA下调了另2种转运蛋白，即长链酰基辅酶A合成酶-1基因(ACSL1)和脂肪酸结合蛋白-3 (FABP3)基因的表达（P<0.01）；2）LNA对奶牛乳腺上皮细胞脂肪酸合成相关基因表达丰度的影响具有剂量效应，较高浓度（≥5 μmol/L）的LNA极显著降低脂肪酸合成酶(FASN)基因和硬脂酰去饱和酶(SCD)基因mRNA转录水平（P<0.01）；3）LNA的浓度对过氧化物酶体增殖物激活受体-γ(PPARG)基因的mRNA转录水平没有显著影响（P>0.05），但所有浓度的LNA均极显著降低了固醇调节元件结合蛋白-1 (SREBF1)基因的mRNA转录水平（P<0.01）。本试验结果证实，长链脂肪酸LNA对乳腺上皮细胞脂肪酸关键合成酶的基因转录具有抑制作用，而CD36在长链脂肪酸转运进入奶牛乳腺上皮细胞的过程中具有重要作用。

This experiment was conducted to study the effects of free linolenic acid (LNA) on the targeted genes of mammary epithelial cells of dairy cows cultured in vitro, which were related to fatty acid metabolism. In the cultured epithelial cells, the control group was supplemented with BSA replacing FBS, and treatments were supplemented with both BSA and LNA at different concentrations. The experiment lasted for 36 h, and the technique RT-qPCR was used to analyse the transcription level of targeted genes. The results showed as follows: 1) 0.625~5.000 μmol/L LNA significantly upregulated the transcription of CD36 gene (P<0.01), and higher (≥5 μmol/L) LNA downregulated the transcription of acyl-CoA synthetase-isoform-1 and fatty acid-binding protein-3 genes (P<0.01). 2) The transcription level of fatty acid biosynthesis genes had a dose response with LNA. Higher concentration of LNA (≥5 μmol/L) decreased the transcription of fatty acid synthase and stearoyl CoA desaturase-1 genes (P<0.01). 3) The extent of LNA concentration did not affect the transcription of proxiomepro liferater ctivatedreceptor-gama gene (P>0.05), but sterol response element binding protein gene was very sensitive to LNA (P<0.01). This study suggests that long-chain fatty acid LNA inhibits the expression of fatty acid endogenous synthesis genes; however, CD36 plays an important role in the transportation process of fatty acids into the mammary epithelial cells of dairy cows.［Chinese Journal of Animal Nutrition, 2010，22（5）:1342-1349］