IGF-通过PI-3K/AKT/mTOR信号通路对奶牛乳腺上皮细胞泌乳基因的影响

The effect of IGF-I on lactation genes in bovine mammary epithelial cells through the PI-3K/AKT/mTOR

中文关键词: 胰岛素样生长因子Ⅰ  乳腺上皮细胞  乳脂  乳蛋白  乳糖

英文关键词: insulin-like growth factor I  Mammary epithelial cells  Milk fat  Milk protein  lactose

中文摘要:

      为了研究外源添加的胰岛素样生长因子Ⅰ（insulin-like growth factor-Ⅰ,IGF-Ⅰ）通过PI-3K/AKT/mTOR信号通路对奶牛乳腺上皮细胞（Bovine Mammary Gland Epithelial Cells,BMECs）乳脂、乳蛋白、乳糖相关基因表达的影响。本试验分采取对照组和试验组相互对照，试验组分为3个，即试验组1为细胞中添加25μg/mL的IGF-Ⅰ组、试验组2为添加25 μmol/L PI3K信号特异性阻断剂LY294002组、试验组3为既添加阻断剂LY294002又添加IGF-Ⅰ组，对照组为单纯培养，仅添加与试验组等体积的完全培养基。每组均做3个平行，每个平行3个重复，培养24 h后，吸取各组上清液，并运用荧光定量PCR检测泌乳相关基因的表达量。试验结果表明，对照组与试验组无显著差异，但添加25g/mL的IGF-Ⅰ对信号通路相关基因有促进趋势，添加阻断剂则减少。对于乳脂合成的重要酶乙酰辅酶A羧化酶（ACACA）来说，试验组1和对照组相比无显著差异，试验组2和3则显著低于对照组（P<0.05），对乳蛋白的表达对照组和试验组之间无显著差异，但试验组1有增长趋势。这说明IGF-Ⅰ对乳脂、乳蛋白的合成具有一定的作用，但是对乳糖的作用不如对乳脂乳蛋白的好。PI-3K/AKT/mTOR也是对乳脂乳蛋白合成的主要通路之一，可能对乳糖的调节起到的作用较弱。

英文摘要:

      In order to investigate the effects of exogenous insulin-like growth factor-I (IGF-I) on the expression of milk fat, milk protein, and lactose related genes in bovine mammary epithelial cells (BMECs) through the PI-3K/AKT/mTOR signaling pathway. This experiment was divided into a control group and an experimental group for mutual control. The experimental groups were divided into three groups, namely, experimental group 1 added 25 μ g/mL IGF-I to the cells, experimental group 2 added 25 μ mol/L PI3K signal specific blocker LY294002, experimental group 3 added both inhibitor LY294002 and IGF-I, and the control group was cultured alone with only the same volume of complete culture medium as the experimental group. Three replicates were performed in each group, with three replicates per replicate. After 24 hours of cultivation, the supernatant from each group was collected and the expression levels of lactation related genes were detected using fluorescence quantitative PCR. The experimental results showed that there was no significant difference between the control group and the experimental group, but the addition of 25g/mL IGF-I promoted signaling pathway related genes, while the addition of inhibitors reduced them. For the important enzyme acetyl CoA carboxylase (ACACA) involved in milk fat synthesis, there was no significant difference between experimental group 1 and the control group, while experimental groups 2 and 3 were significantly lower than the control group (P<0.05). There was no significant difference in the expression of milk protein between the control and experimental groups, but experimental group 1 showed an increasing trend. This indicates that IGF-I has a certain effect on the synthesis of milk fat and milk protein, but its effect on lactose is not as good as its effect on milk fat and milk protein. PI-3K/AKT/mTOR is also one of the main pathways involved in the synthesis of milk fat and milk proteins, and may have a weaker role in regulating lactose.