Maternal treatment with somatotropin during early gestation affects basic events of myogenesis in pigs
Maternal treatment with somatotropin during early gestation affects basic events of myogenesis in pigs
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DOI：
10.1007/s00441-001-0475-x
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发表时间：
2001-10
影响因子：
3.6
通讯作者：
C. Rehfeldt;G. Kuhn;J. Vanselow;R. Fürbass;I. Fiedler;G. Nürnberg;A. Clelland;N. Stickland;K. Ender
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文献类型：
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作者：
C. Rehfeldt;G. Kuhn;J. Vanselow;R. Fürbass;I. Fiedler;G. Nürnberg;A. Clelland;N. Stickland;K. Ender
确定了妊娠早期母亲使用生长激素治疗对胎儿肌肉发育的影响。从妊娠第 10 天到第 27 天，杂交后备母猪每天接受 3 ml 安慰剂 (n=31) 或 6 mg 猪生长激素 (n=31) 注射，并从第 28 天胚胎、第 37 天和第 62 天胎儿以及新生儿收集样本。生长激素的施用增加了中体重和低体重同窝新生儿半腱肌的纤维总数（初级和次级纤维），而腰大肌没有观察到增加。生长激素诱导肌肉蛋白浓度、肌酸激酶活性、肌纤维周长以及 II 型纤维向 I 型纤维转化的增加，这揭示了出生时的高级分化程度。治疗对产前发育的影响先于这些变化。妊娠第 28 天 DNA 浓度增加表明胚胎阶段细胞增殖受到刺激。此后，与妊娠第 37 天的对照组相比，生长激素的停用导致分化短暂延迟，表现为较低的蛋白质浓度和肌酸激酶活性。这在第 62 天再次得到补偿，中等体重胎儿的半腱肌初级纤维数量增加，而次级或总纤维数量尚未差异。然而，Myf5和Myo表达的增强表明最初确定的增殖性成肌细胞数量较多，这可能有助于次级纤维形成的增加。总之，母体生长激素是妊娠早期的一个影响因素，能够影响肌生成的基本事件。
The effects of maternal treatment with somatotropin during early gestation on fetal muscle development were determined. Crossbred gilts received daily injections of either 3 ml of a placebo (n=31) or of 6 mg porcine somatotropin (n=31) from day (d) 10 to 27 of gestation and samples were collected from d 28 embryos, d 37 and 62 fetuses, and from neonates. Administration of somatotropin increased the total number of fibres (primary and secondary fibres) in neonatal semitendinosus muscle of middle- and low-weight littermates, whilst no increase was observed in psoas major muscle. Somatotropin induced increases in muscular protein concentration, creatine kinase activity, muscle fibre girth, as well as type II to type I fibre conversion which revealed an advanced degree of differentiation at birth. Treatment effects on prenatal development preceded these changes. Increased DNA concentrations at d 28 of gestation indicate stimulation of cellular proliferation during the embryonic stages. Thereafter, the withdrawal of somatotropin caused a transient delay of differentiation as indicated by lower protein concentrations and creatine kinase activity compared with controls at d 37 of gestation. This was compensated again at d 62, and the number of semitendinosus primary fibres was increased in middle-weight fetuses, whereas secondary or total fibre number did not yet differ. However, enhanced expression ofMyf5andMyoDindicates higher numbers of initially determined, proliferating myoblasts that may have contributed to increased formation of secondary fibres. In conclusion, maternal somatotropin is an influential factor in early pregnancy capable of affecting the basic events of myogenesis.