Grant A L, Helferich W G, Merkel R A, Bergen W G
Dept. of Anim. Sci., Michigan State University, East Lansing 48824.
J Anim Sci. 1990 Mar;68(3):652-8. doi: 10.2527/1990.683652x.
Satellite cells were isolated from 20-d embryonic chick breast muscle via a Percoll density gradient fractionation technique. Culturing of these cells gave rise to at least 89% fusion (myotube nuclei number/total nuclei number). Proliferation of cultured satellite cells (indicated by myotube nuclei number) was increased in a dose-dependent manner when fibroblast growth factor (FGF) was included in the medium (25 to 200 ng/ml). Similar cultures were used to examine the effects of ractopamine and isoproterenol on satellite cell proliferation. Ractopamine and isoproterenol were added to culture medium (10(-11) to 10(-4) M) 24 h after initial plating. After a 72-h treatment period, the treatments were removed and replaced with a medium to promote fusion for 48 h. Cells then were fixed and stained, and myotube and total nuclei were counted. In later experiments, ractopamine and isoproterenol each increased (P less than .01) myotube nuclei number vs that observed in control cultures by 2.3 and 2.1 times, respectively. Similar differences were observed with total nuclei number. The number of myotube nuclei observed in cultures treated with 10(-6) M ractopamine or isoproterenol was reduced (P less than .01) by 25.4 and 23.6%, respectively, when propranolol, a beta adrenergic antagonist, was included at 10(-5) M with the respective agonist. These results indicate that ractopamine and isoproterenol each enhance the proliferative activity of chick satellite cells in culture and that the beta adrenergic receptor mediates this proliferative effect.
通过Percoll密度梯度分级技术从20日龄胚胎鸡的胸肌中分离出卫星细胞。这些细胞培养后至少有89%发生融合（肌管细胞核数/总细胞核数）。当培养基中加入成纤维细胞生长因子（FGF，25至200 ng/ml）时，培养的卫星细胞增殖（以肌管细胞核数表示）呈剂量依赖性增加。使用类似的培养物来研究莱克多巴胺和异丙肾上腺素对卫星细胞增殖的影响。在初始接种24小时后，将莱克多巴胺和异丙肾上腺素添加到培养基中（10⁻¹¹至10⁻⁴ M）。经过72小时的处理期后，去除处理物，换成促进融合的培养基培养48小时。然后将细胞固定并染色，计数肌管和总细胞核。在后续实验中，与对照培养物相比，莱克多巴胺和异丙肾上腺素各自使肌管细胞核数分别增加了2.3倍和2.1倍（P <.01）。总细胞核数也观察到类似差异。当在含有10⁻⁶ M莱克多巴胺或异丙肾上腺素的培养物中加入10⁻⁵ M的β肾上腺素能拮抗剂普萘洛尔时，观察到的肌管细胞核数分别减少了25.4%和23.6%（P <.01）。这些结果表明，莱克多巴胺和异丙肾上腺素各自增强了培养的鸡卫星细胞的增殖活性，并且β肾上腺素能受体介导了这种增殖效应。
