地塞米松对胎鼠骨骼肌发育相关基因表达的影响

Effects of Dexamethasone on Expression of Skeletal Muscle Development Related Genes in Fetal Mice

为了研究母体应激对胎鼠骨骼肌发育及相关基因表达的影响,对孕期12 d的母鼠连续3 d(每天一次)注射地塞米松(Dex)以建立母体应激模型,使用ELISA试剂盒检测孕鼠胎盘羊水中糖皮质激素(Glucocorticoid,GC)含量的变化,采用HE染色法观察胎鼠骨骼肌的显微结构,利用荧光定量PCR分析相关基因的表达,并利用生物信息学软件对相关基因5'调控区元件进行预测。结果表明,Dex处理组孕鼠胎盘羊水中的GC含量显著升高,胎鼠骨骼肌发育受损,Myostatin基因表达显著上调,而Pax3和Pax7表达明显下调。进一步生物信息学分析结果表明,Myostatin、Pax3和Pax7基因的5′调控区均含有糖皮质激素受体元件(GRE),Myostatin基因的5′调控区同时存在PAX7元件,Pax3、Pax7基因的5′调控区还分别存在PAX7、PAX3元件,其调控机制可能是Dex通过糖皮质激素受体(GR)结合于靶标基因启动子区的GRE元件而发挥直接或间接的调控作用。研究结果可为深入研究家畜等动物母体应激影响子代骨骼肌发育的分子机制并探讨相应的防治措施奠定基础。

To study the effects of maternal stress on the skeletal muscle development and the related genes expression in fetal mice,Dexamethasone(Dex)was injected into female mice from the 12 d of gestation for three consecutive days(once a day)to establish a model of maternal stress.The change of Glucocorticoid(GC)content in placental amniotic fluid of pregnant mice was detected by ELISA kit.The microstructure of fetal mice skeletal muscle was observed by HE staining method.The expression of related genes was analyzed by fluorescence quantitative PCR.The 5'regulatory region elements of related genes were predicted using bioinformatics software.The results showed that the GC content in the placental amniotic fluid of pregnant mice in the Dex treatment group significantly increased.The development of fetal mice's skeletal muscle was impaired.The expression of Myostatin was significantly up-regulated,while the expression of Pax3 and Pax7 significantly down-regulated in the fetal mice's skeletal muscle.Further bioinformatics analysis showed that the 5′regulatory regions of Myostatin,Pax3 and Pax7 genes contained glucocorticoid receptor elements(GRE),and the 5′regulatory regions of Myostatin genes also contained PAX7 elements,and the 5′regulatory regions of Pax3 and Pax7 genes contained respectively PAX7 and PAX3 elements,which indicated that Dex played a direct or indirect regulatory role through glucocorticoid receptor(GR)binding to GRE element in target gene promoter region.This test results will lay a foundation for further studying the molecular mechanisms about the effects of maternal stress on the fetal skeletal muscle development of livestock and exploring the corresponding prevention and treatment measures.