Banu J, Orhii P B, Okafor M C, Wang L, Kalu D N
Department of Physiology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr., San Antonio, TX 78229, USA.
Mech Ageing Dev. 2001 Jun;122(8):849-64. doi: 10.1016/s0047-6374(01)00243-3.
The aim of this study is to determine the effects of growth hormone (GH), exercise (EX), GH+EX and food restriction on cancellous bone in middle-aged female rats. Female F344 rats aged 13 months were divided into (1) age-matched controls; (2) GH treated (2.5 mg/kg. 5 day/week); (3) EX (voluntary wheel running); (4) GH+EX; and (5) food restricted (FR) (fed 60% of the ad libitum food intake). The animals were treated for 18 weeks, at the end of which they were sacrificed. Cancellous bone and cortical bone in the fourth lumbar vertebra, proximal tibial metaphysis (PTM), distal femoral metaphysis (DFM) and femoral neck (NF) were analyzed using peripheral quantitative computerized tomography (pQCT) densitometry. Growth hormone increased cancellous bone area, cancellous bone mineral content, cortical bone area and cortical bone mineral content in the vertebra, PTM, DFM and NF. The tibial muscle wet weight was increased significantly after GH treatment. Exercise increased the cancellous bone area in the vertebra, PTM and DFM. Cortical bone area and cortical bone mineral content increased after EX in the vertebra, PTM, DFM and NF. No significant change was seen in the tibial muscle wet weight after EX. Growth hormone+EX increased cancellous bone area in the vertebra PTM and DFM but had no effect in neck of the femur. Cancellous bone mineral content, cortical bone area and cortical bone mineral content increased with GH+EX in the vertebra, PTM, DFM and NF. The tibial muscle wet weight was increased significantly with GH+EX. Food restriction decreased cancellous bone area and cancellous bone mineral content in all the bones studied. The decrease was statistically significant only at the distal femoral metaphysis. The tibial muscle wet weight decreased when compared with the age-matched control, but this decrease was not statistically significant. We conclude that the effect of the dose of GH used and the levels of voluntary wheel running EX used increased cancellous bone in intact rats; the effect of GH is much greater and different bones respond with varying intensities. The effects of combined treatment of GH and EX on cancellous bone are not always significantly higher than those of GH alone. FR at the level studied has a mostly negative effect on cancellous bone.
本研究的目的是确定生长激素（GH）、运动（EX）、GH+EX以及食物限制对中年雌性大鼠松质骨的影响。将13月龄的雌性F344大鼠分为：（1）年龄匹配的对照组；（2）接受GH治疗组（2.5mg/kg，每周5天）；（3）运动组（自愿轮转跑步）；（4）GH+EX组；以及（5）食物限制组（FR）（喂食量为随意进食量的60%）。对动物进行18周的治疗，治疗结束后将它们处死。使用外周定量计算机断层扫描（pQCT）骨密度测定法分析第四腰椎、胫骨近端干骺端（PTM）、股骨远端干骺端（DFM）和股骨颈（NF）的松质骨和皮质骨。生长激素增加了椎骨、PTM、DFM和NF处的松质骨面积、松质骨矿物质含量、皮质骨面积和皮质骨矿物质含量。GH治疗后胫骨肌肉湿重显著增加。运动增加了椎骨、PTM和DFM处的松质骨面积。运动后椎骨、PTM、DFM和NF处的皮质骨面积和皮质骨矿物质含量增加。运动后胫骨肌肉湿重未见显著变化。GH+EX增加了椎骨、PTM和DFM处的松质骨面积，但对股骨颈无影响。GH+EX使椎骨、PTM、DFM和NF处的松质骨矿物质含量、皮质骨面积和皮质骨矿物质含量增加。GH+EX使胫骨肌肉湿重显著增加。食物限制减少了所有研究骨骼中的松质骨面积和松质骨矿物质含量。仅在股骨远端干骺端，这种减少具有统计学意义。与年龄匹配的对照组相比，胫骨肌肉湿重下降，但这种下降无统计学意义。我们得出结论，所使用的GH剂量和自愿轮转跑步运动水平增加了完整大鼠的松质骨；GH的作用更大，不同骨骼的反应强度不同。GH和EX联合治疗对松质骨的影响并不总是显著高于单独使用GH的影响。在所研究的水平上，食物限制对松质骨大多具有负面影响。
