饥饿和复投喂对大黄鱼(Larimichthys crocea)IGF-Ⅰ、mTOR、MyoD和MHC基因表达的影响

EFFECTS OF STARVATION AND REFEEDING ON THE EXPRESSION OF IGF-Ⅰ,MTOR, MYOD, AND MHC IN LARGE YELLOW CROAKER LARIMICHTHYS CROCEA

为从分子水平研究饥饿对大黄鱼肌肉生长代谢的影响,本实验采用qPCR技术研究了在饥饿胁迫以及复投喂过程中胰岛素样生长因子基因IGF-Ⅰ(insulin-like growth fator-Ⅰ)、雷帕霉素靶蛋白基因mTOR(mammalian target of rapamycin)、成肌分化抗原基因MyoD(myogenic differentiationantigen)和肌球蛋白重链基因MHC(myosin heavy chain)等4个大黄鱼肌肉生长调控相关基因在肝脏、脾脏、脑、心脏、肠、鳃、肌肉和肾8个组织中的表达模式。结果显示:四个基因在正常大黄鱼不同组织间表达存在显著差异;饥饿显著降低IGF-Ⅰ在肝组织中的表达量(P<0.05),在复投喂14d时显著上升,此外在肠和鳃组织中表达量变化显著(P<0.05);mTOR表达量随着饥饿时间的延长,在脾、心和肾组织中表达量下降,在脑、鳃和肌肉组织中表达量显著升高(P<0.05);MyoD在饥饿胁迫和恢复投喂期间,在肝脏、鳃和肌肉组织中表达量变化极显著(P<0.01);饥饿和恢复投喂对MHC在鳃和肌肉中的表达影响显著(P<0.05)。结果提示饥饿可能通过调节这些肌肉生长相关基因的表达来影响肌肉的生长。

To study the effect of starvation on muscle growth and metabolism of large yellow croaker Larimichthys crocea at molecular level,the expression patterns of four major muscle growth regulation genes,including insulin-like growth factor-I(IGF-Ⅰ),mammalian target of rapamycin(mTOR),myogenic differentiation antigen(MyoD),and myosin heavy chain(MHC),were detected by qPCR in liver,spleen,brain,heart,intestine,gill muscle and kidney tissues.The results show significant differences in the expression patterns of four genes in the different tissues.The IGF-Ⅰexpression level significantly decreased under starvation stress and increased after 14d refeeding in liver tissue(P<0.05).In addition,the IGF-ⅠmRNA level significantly changed in intestine and gill tissues during starvation.The expression levels of mTOR gradually decreased in spleen,heart,and kidney tissues with the prolongation of starvation time(P<0.05)but the expression levels in brain,gill,and muscle tissues were significantly increased(P<0.05).The MyoD expression levels in liver,gill,and muscle tissues changed significantly during starvation and refeeding(P<0.01).Starvation and refeeding had a significant effect on the expression of MHC in the gill and muscle(P<0.05).Therefore,the muscle proliferation of large yellow croaker is achieved by regulating the expression of these genes in order to cope with starvation stress.