脂肪酸结合蛋白5对奶牛乳腺上皮细胞乳脂合成的影响

Effect of Fatty Acid Binding Protein 5 on Milk Fat Synthesis of Bovine Mammary Epithelial Cells

脂肪酸结合蛋白5(fatty acid binding protein 5,FABP5)是一种胞内脂质运载体。本试验应用甘油三酯测定法及BODIPY染色法检测奶牛乳腺上皮细胞(bovine mammary epithelial cell,BMEC)中甘油三酯及脂滴分泌情况,采用实时荧光定量PCR、Western blotting技术检测BMECs中FABP5对固醇调节元件结合蛋白-1c(SREBP-1c)的表达影响。结果显示,试验成功获得高纯度的BMECs,构建了pGCMV-IRES-EGFP-FABP5真核表达载体,且与空白对照组和空载体组相比,FABP5过表达组的甘油三酯和脂滴分泌量极显著增加(P<0.01),同时SREBP-1c及靶基因FAS、ACC的表达量均极显著增加(P<0.01);试验成功筛选了FABP5siRNA1为最佳干扰片段,当FABP5抑制时,抑制组的甘油三酯、脂滴分泌量极显著减少(P<0.01),SREBP-1c、FAS、ACC的表达量均极显著降低(P<0.01)。表明FABP5可通过上调SREBP-1c的表达从而促进BMEC中乳脂的合成。

The fatty acid binding protein 5 （FABPS） is an intracellular lipid carrier. The TG GPO-POD assay kit and BODIPY staining methods were used to detect lipid secretion and triglyceride content,and the effect of FABP5 on SREBP-1c expression were detected by Real-time PCR and Western blotting methods. The results showed that high purity bovine mammary epithelial cells （BMECs） were successfully isolated and purified,and the eukaryotic expression vector pGCMV-IRES-EGFP-FABP5 was constructed in this experiment. Compared with the blank control group and empty vector group,the lipid secretion and triglyceride content, and the expression of SREBP-lc and FAS, ACC were extremely significantly increased when the FABP5 was overexpressed （P〈0.01）. FABP5 siRNA1 was selected as the optimal interference fragment, and when FABP5 was inhibited, the lipid secretion and triglyeeride content, the expression of SREBP-1c, FAS and ACC were extremely significantly FABP5 could promote the synthesis of milk decreased （P 〈 0. 01）. The results indicated that fat in BMEC by up-regulating the expression of SREBP-1c.