Li Y, Wang Y, Willems E, Willemsen H, Franssens L, Buyse J, Decuypere E, Everaert N
Department of Biosystems, Division of Livestock-Nutrition-Quality, KU Leuven, Leuven, Belgium.
Laboratory of Translational Medicine, Jiangsu Province Academy of Traditional Chinese Medicine, Nanjing, Jiangsu, China.
J Anim Physiol Anim Nutr (Berl). 2016 Feb;100(1):167-77. doi: 10.1111/jpn.12299. Epub 2015 Apr 3.
In this study, we tested the hypothesis that in ovo feeding (IOF) of L-arginine (L-Arg) enhances nitric oxide (NO) production, stimulates the process of myogenesis, and regulates post-hatching muscle growth. Different doses of L-Arg were injected into the amnion of chicken embryos at embryonic day (ED) 16. After hatching, the body weight of individual male chickens was recorded weekly for 3 weeks. During in vitro experiments, myoblasts of the pectoralis major (PM) were extracted at ED16 and were incubated in medium containing 0.01 mm L-Arg, 0.05 mm L-Arg, and (or) 0.05 mm L-nitro-arginine-methyl-ester (L-NAME), an inhibitor of nitric oxide synthase (NOS). When 25 mg/kg L-Arg/initial egg weight was injected, no difference was observed in body weight at hatch, but a significant decrease was found during the following 3 weeks compared to that of the non-injected and saline-injected control, and this also affected the growth of muscle mass. L-NAME inhibited gene expression of myogenic differentiation antigen (MyoD), myogenin, NOS, and follistatin, decreased the cell viability, and increased myostatin (MSTN) gene expression. 0.05 mm L-Arg stimulated myogenin gene expression but also depressed muscle cell viability. L-NAME blocked the effect of 0.05 mm L-Arg on myogenin mRNA levels when co-incubated with 0.05 mm L-Arg. L-Arg treatments had no significant influence on NOS mRNA gene expression, but had inhibiting effect on follistatin gene expression, while L-NAME treatments had effects on both. These results suggested that L-Arg stimulated myoblast differentiation, but the limited number of myoblasts would form less myotubes and then less myofibers, while the latter limited the growth of muscle mass.
在本研究中，我们验证了以下假设：在鸡胚中注射L-精氨酸（L-Arg）可增强一氧化氮（NO）的生成，刺激肌生成过程，并调节孵化后肌肉的生长。在胚胎发育第16天（ED16），将不同剂量的L-Arg注射到鸡胚的羊膜中。孵化后，每周记录个体雄性雏鸡的体重，持续3周。在体外实验中，于ED16提取胸大肌（PM）的成肌细胞，并在含有0.01 mM L-Arg、0.05 mM L-Arg和（或）0.05 mM L-硝基精氨酸甲酯（L-NAME，一氧化氮合酶（NOS）抑制剂）的培养基中孵育。当以25 mg/kg L-Arg/初始蛋重进行注射时，孵化时体重未观察到差异，但与未注射和注射生理盐水的对照组相比，在随后3周体重显著下降，这也影响了肌肉质量的增长。L-NAME抑制成肌分化抗原（MyoD）、生肌调节因子、NOS和卵泡抑素的基因表达，降低细胞活力，并增加肌肉生长抑制素（MSTN）基因表达。0.05 mM L-Arg刺激生肌调节因子基因表达，但也降低肌肉细胞活力。当与0.05 mM L-Arg共同孵育时，L-NAME阻断了0.05 mM L-Arg对生肌调节因子mRNA水平的影响。L-Arg处理对NOS mRNA基因表达无显著影响，但对卵泡抑素基因表达有抑制作用，而L-NAME处理对两者均有影响。这些结果表明，L-Arg刺激成肌细胞分化，但有限数量的成肌细胞形成的肌管较少，进而形成的肌纤维较少，而后两者限制了肌肉质量的增长。
