| Summary: | 【Abstract】Objective: 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.
Methods: A total of 40 adult male Spragne-Dawley rats
were divided into two groups (experimental group and con-trol 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 µg/kg 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-poly-merase chain reaction (RT-PCR) assay.
Results: There was a significant increase in the bone
mineral density of experimental group compared with con-trol group. There was a significant decrease in the level of
receptor activator of nuclear factor-κB -ligand but an
increase in the level of osteoprotegerin 4 and 6 weeks after
neurectomy in the experimental group compared with con-trol one. The expression of Osterix and Runx2 was up-regu-lated in the bone marrow of experimental group compared with
control group.
Conclusion: 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.
Key words: Osteoporosis; Sciatic nerve; Osteoblasts;
Insulin-like growth factor 1
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