与脐带间充质干细胞共培养对奶牛乳腺上皮细胞乳脂合成及关键基因表达的影响

Expression of key genes of milk fat synthesis in bovine mammary gland epithelial cells co-culture with umbilical cord mesenchymal stem cells

探究与脐带间充质干细胞共培养对奶牛乳腺上皮细胞（BMECs）乳脂合成及关键基因表达的影响。将脐带间充质干细胞和乳腺上皮细胞利用Transwell小室双层共培养，BMECs单纯培养为对照组，IGF—IR抑制剂AG1024处理细胞，检测上清IGF—I、甘油三酯（TAG）含量变化，再用磷脂酰肌醇3一羟激酶（P13K）信号阻断剂LY294002孵育细胞，RT—qPCR检测乙酰辅酶A羧化酶（ACACA）、脂肪酸合成酶（FASN）和固醇调节元件结合蛋白（sterol regulatory element,bindingproteins，SREBP1）基因的相对表达丰度。结果显示，共培养后BMECs的IGF—I含量极显著升高（P〈0．01），TAG含量显著升高（P〈0．05）；加入AG1024后，IGFI明显受到抑制（P〈0．01），显著降低了各组TAG含量及各基因的表达丰度（P〈0．05）；LY294002抑制了P13K（P〈0．01）、AKT、mTOR（P〈0．05）mRNA的表达，显著降低了TAG含量及ACACA、FASN、SREBPlmRNA的表达（P〈0．05）；共同处理后极显著降低了TAG合成量及各基因相对表达丰度（P〈0．01）。结果表明，脐带间充质干细胞能够通过IGF—I介导P13K／Akt／mTOR信号通路上调BMECs乳脂合成关键基因的表达丰度，促进TAG的合成。

To explore the expression of key genes of milk fat synthesis in bovine mammary gland epithelial cells （BMECs） co-culture with umbilical cord mesenchymal stem cells. UC MSCs and BMECs were co-cultured by Transwell double chamber, BMECs cultured alone as control group, each group was intervented by IGF I R inhibitor AG1024,and determined the IGF-I,triglyceride （TAG） content of supernatant, then phosphatidylinositol-3-kinase hydroxyl （PI3K） inhibitor LY294002 incubated cells, the relative expression abundance of ACACA, FASN and SREBPlmRNA were detected by RT PCR. Results showed that the content of IGF-I in BMECs was extremely significant higher than BMECs group after co-cuhured with UC-MSCs（P〈0.01）, and the content of TAG was significantly higher（P〈0.05） ;the addition of AG1024 has a very sig- nificant inhibitory effect on IGF-I（P〈0.01） ,the TAG content and ACACA,FASN,SREBP1 mR- NA relative abundance expression of BMECs were significantly reduced（P〈0.05）;the expression of PI3K （P 〈 0. 01）, AKT, mTOR （P 〈 0. 05） mRNA were inhibited by LY294002, the TAG content and ACACA,FASN, SREBP1 mRNA relative abundance expression of BMECs were significantly reduced（P〈0.05）;after adding I.Y294002 on the basis of AG1024, the content of TAG and the expression of every gene were extremely reduced. UC-MSCs can promote BMECs milk fat synthesis and the expression of key gene by IGF-I mediated PI3K/Akt/mTOR signaling pathway.