Grubbe M-C, Thomsen J S, Nyengaard J R, Duruox M, Brüel A
Department of Biomedicine, Aarhus University, Aarhus, Denmark.
J Musculoskelet Neuronal Interact. 2014 Dec;14(4):473-83.
Growth hormone (GH) is a potent anabolic agent capable of increasing both bone and muscle mass. The aim was to investigate whether GH could counteract disuse-induced loss of bone and muscle mass in a rat model. Paralysis was induced by injecting 4 IU Botox (BTX) into the muscles of the right hind limb. Sixty female Wistar rats, 14 weeks old, were divided into the following groups: baseline, controls, BTX, BTX+GH, and GH. GH was given at a dosage of 5 mg/kg/d for 4 weeks. Compared with controls, BTX resulted in lower periosteal bone formation rate (BFR/BS,-79%, P<0.001), bone mineral density (aBMD, -13%, P<0.001), trabecular bone volume (BV/TV, -26%, P<0.05), and mid-femoral bone strength (-12%, P<0.05). In addition, BTX reduced rectus femoris muscle mass (-69%, P<0.001) and muscle cell cross sectional area (CSA) (-73%, P<0.001) compared with controls. GH counteracted disuse-induced losses of periosteal BFR/BS (2-fold increase vs. BTX, P<0.001), whereas no effect on aBMD, trabecular BV/TV, or bone strength was found. In addition, GH partly prevented loss of muscle mass (+29% vs. BTX, P<0.001), and tended to prevent loss of muscle CSA (+11%, P=0.064). In conclusion, GH mitigates disuse-induced loss of periosteal BFR/BS at the mid-femur and rectus femoris muscle mass.
生长激素（GH）是一种强效合成代谢剂，能够增加骨量和肌肉量。本研究旨在探讨生长激素是否能对抗大鼠模型中因废用导致的骨量和肌肉量丢失。通过向右侧后肢肌肉注射4国际单位肉毒杆菌毒素（BTX）诱导瘫痪。将60只14周龄的雌性Wistar大鼠分为以下几组：基线组、对照组、BTX组、BTX+GH组和GH组。以5mg/kg/d的剂量给予生长激素，持续4周。与对照组相比，BTX导致骨膜骨形成率（BFR/BS，-79%，P<0.001）、骨矿物质密度（aBMD，-13%，P<0.001）、骨小梁骨体积（BV/TV，-26%，P<0.05）和股骨中段骨强度（-12%，P<0.05）降低。此外，与对照组相比，BTX使股直肌肌肉量减少（-69%，P<0.001），肌肉细胞横截面积（CSA）减少（-73%，P<0.001）。生长激素可对抗因废用导致的骨膜BFR/BS丢失（与BTX组相比增加2倍，P<0.001），而对aBMD、骨小梁BV/TV或骨强度无影响。此外，生长激素部分预防了肌肉量的丢失（与BTX组相比增加29%，P<0.001），并倾向于预防肌肉CSA的丢失（增加11%，P=0.064）。总之，生长激素可减轻因废用导致的股骨中段骨膜BFR/BS和股直肌肌肉量丢失。
