Sun Hai-Biao, Chen Jun-Chang
Xi'an Jiaotong University Medical School, Xi'an 710049, China.
Chin J Traumatol. 2013;16(3):158-62.
Injection of insulin-like growth factor-1 (IGF-1) can prevent bone loss in sciatic nerve transaction rats. We try to investigate the action mechanism of IGF-1 on bone formation.
A total of 40 adult male Spragne-Dawley rats were divided into two groups (experimental group and control group) with 20 animals in each. Sciatic neurectomy was performed to model disuse osteoporosis in all rats. IGF-1 was administered in experimental group with the dose of 100 microgramme/kilogram per day for 3 days. Meanwhile, the rats in control group were treated with saline. Bone mineral density was measured by dual-energy X-ray absorptiometry 4 and 6 weeks after neurectomy respectively. Expression of Osterix and Runx2 was determined by reverse transcription-polymerase chain reaction (RT-PCR) assay.
There was a significant increase in the bone mineral density of experimental group compared with control group. There was a significant decrease in the level of receptor activator of nuclear factor-kappaB-ligand but an increase in the level of osteoprotegerin 4 and 6 weeks after neurectomy in the experimental group compared with control one. The expression of Osterix and Runx2 was up-regulated in the bone marrow of experimental group compared with control group.
IGF-1 can increase bone formation by stimulation of osteoblast number and activity, and reduce bone resorption by restriction of differentiation of osteoclast, suggesting that IGF-1 may improve the therapeutic efficacy for disuse osteoporosis.
注射胰岛素样生长因子-1（IGF-1）可预防坐骨神经切断大鼠的骨质流失。我们试图研究IGF-1对骨形成的作用机制。
将40只成年雄性Sprague-Dawley大鼠分为两组（实验组和对照组），每组20只。对所有大鼠进行坐骨神经切除术以建立废用性骨质疏松模型。实验组给予IGF-1，剂量为每天100微克/千克，共3天。同时，对照组大鼠用生理盐水治疗。分别在神经切断术后4周和6周通过双能X线吸收法测量骨密度。通过逆转录-聚合酶链反应（RT-PCR）测定法测定Osterix和Runx2的表达。
与对照组相比，实验组的骨密度显著增加。与对照组相比，实验组在神经切断术后4周和6周时核因子-κB配体受体激活剂水平显著降低，但骨保护素水平升高。与对照组相比，实验组骨髓中Osterix和Runx2的表达上调。
IGF-1可通过刺激成骨细胞数量和活性增加骨形成，并通过限制破骨细胞分化减少骨吸收，提示IGF-1可能提高废用性骨质疏松的治疗效果。
