中文摘要：

[目的]在骨骼肌生长或损伤刺激下，骨骼肌卫星细胞被激活、增殖分化形成肌管，促进骨骼肌的生长发育或修复组织创伤。FoxO1负调控骨骼肌的生成，但在骨骼肌卫星细胞分化过程中的作用未见报道。因此，笔者探索FoxO1对猪骨骼肌卫星细胞分化的影响，希望为深入研究FoxO1调控骨骼肌生长发育的作用机理奠定基础。[方法]以1-3日龄健康大白猪为材料，采用单根肌纤维法分离培养猪骨骼肌卫星细胞，接种第2天、第4天和第6天在倒置显微镜下观察细胞形态并拍照。在细胞分化第8天，用免疫荧光染色方法染肌管，DAPI染核，并在荧光倒置显微镜下观察拍照。待细胞汇合至70%-80%时，将培养基换成含50 nmol＆#183;L-1渥曼青霉素（wortmannin，WM）的分化培养基，分别于细胞分化第0天、第4天和第8天收集细胞，提取总RNA和总蛋白，采用real-time qPCR和Western blotting方法检测WM对FoxO1以及骨骼肌卫星细胞分化标志基因表达的影响。[结果]猪骨骼肌卫星细胞在接种第2天开始贴壁，呈梭形。第4天细胞数量增加，部分发生融合。第6天时细胞呈方向性生长。第8天细胞进一步融合形成肌管。WM处理组的FoxO1 mRNA表达水平未发生显著变化（P＞0.05），非磷酸化的FoxO1蛋白表达显著高于对照组（P＜0.05），而p-FoxO1蛋白表达较对照组显著下降（P＜0.05）。WM处理组的细胞在分化第8天，虽然也出现了蜂窝状生长，但是与对照组相比细胞未呈方向性生长并形成肌管。Western blotting结果显示，WM明显抑制猪骨骼肌卫星细胞分化早期标志基因MyoD、中后期标志基因MyoG和末期标志基因MyHC蛋白的表达。[结论]以WM阻断PI3K信号通路能使FoxO1去磷酸化，抑制猪骨骼肌卫星细胞的分化，延迟肌管的形成，并降低成肌分化标志基因MyoD、MyoG和MyHC的表达。总之，阻断PI3K信号通路通过激活FoxO1抑制猪骨?

英文摘要：

[Objective]Skeletal satellite cells are activated by some specific stresses such as development and trauma, and differentiate and form myotubes to participate in the development or repair of skeletal muscle. FoxO1 negatively controls the genesis of skeletal muscle, but the molecular mechanisms by which FoxO1 funcions in the differentiation of satellite cells have not been reported so far. This experiment was conducted to explore the effects of FoxO1 on porcine skeletal muscle satellite cells differentiation, aiming to provide new theoretical reference for further research. [Method]Extensor digitorum longus of 1 to 3-day-old piglets were used to isolate the skeletal muscle satellite cells and the cells were observed and pictures were taken by inverted microscope on day 2, day 4 and day 6, respectively. The cells were stained by immunofluorescence staining and DAPI nuclear staining on day 8 of differentiation, and observed under a fluorescence microscope. Meanwhile, the medium was replaced with differentiation medium containing 50 nmol＆#183;L-1 wortmannin （wortmannin, WM） differentiation medium when the cells density reached 70%-80%confluence, the cells were collected on day 0, day 4, and day 8, respectively. Total RNA and total protein were extracted, and Real-time qPCR and Western blotting were performed to measure the alterations in the expression of FOXO1 and myogenic differentiation marker genes caused by WM supplement.[Result]Porcine skeletal muscle satellite cells became adherent to the dish bottem, spindle-shaped on day 2. Cell number increased on day 4 and some cells started to fuse. On day 6, cell started to grow with directivity. On day 8, cell further fused to form myotubes, further fused to form myotubes. There was no significant difference in mRNA expression level of FoxO1 between WM treatment group and the control （P＆gt;0.05）, unphosphorylated FoxO1 increased significantly （P＆lt;0.05） with WM treatment, whereas phosphorylation level of FoxO1 dropped drastically （P＆lt;0.05）. Al