后肢固定大鼠股骨内生长激素及胰岛素样生长因子Ⅰ和生长抑素水平的改变

背景骨组织内,骨形成和吸收之间的平衡主要与全身和局部的激素和生长因子活性有关,肢体固定能导致骨吸收增加及骨形成减少,从而诱发骨质疏松,但生长因子与骨质疏松之间的关系有待进一步认识.目的通过大鼠后肢固定模型,观察大鼠股骨组织内的生长激素、胰岛素样生长因子Ⅰ和生长抑素的浓度变化.设计随机对照观察实验.材料6月龄清洁级健康雄性SD大鼠50只,体质量290～320g,随机分为固定组40只和对照组10只.方法实验于2002-02/2003-01在青岛大学医学院附属医院创伤外科完成.固定组大鼠右后肢用胶布固定于腹部,随机分为4组,每组10只,分别于1,2,4和8周腹腔内麻醉后处死大鼠.对照组大鼠于8周处死,除未进行固定外,其他处理方法与固定组一致.主要观察指标对照组大鼠和固定1,2,4和8周大鼠股骨组织提取液中生长激素、胰岛素样生长因子Ⅰ和生长抑素的浓度.结果50只大鼠均进入结果分析.生长激素水平在固定第8周组比对照组明显升高[(41.80±8.39),(19.86±4.21)μg/g,P＜0.05];而股骨内的胰岛素样生长因子Ⅰ在第2周出现最高峰,明显高于对照组[(758.23±23.12),(499.60±18.76)μg/g,P＜0.05],但在第4周恢复到对照组水平,在第8周明显减少[(258.65±5.76)μg/g,P＜0.05].生长抑素在固定的第8周明显高于对照组[(51.69±2.36),(34.63±8.85)μg/g,P＜0.05].结论生长激素和胰岛素样生长因子Ⅰ不仅和骨形成有关,且在固定增加骨吸收的情况下,可以引起这些肽类的浓度升高,可能与骨吸收有关.

Alternations of growth hormone, insulin-like growth factor-Ⅰand somatostation in the femurs of hind-limb immobilized rats

BACKGROUND: In bone tissue, the balance between bone formation and resorption is associated with the activities of hormones and growth factors in the whole body and local area. Limb immobilization increases bone resorption and decreases bone formation so that osteoporosis is induced. But a further recognition is expected on the relationship between growth factors and osteoporosis.OBJECTIVE: To observe the changes in concentrations of growth hormone (GH), insulin-like growth factor-Ⅰ (IGF-I) and somatostation in rat model with hind-limb immobilization.DESIGN: Randomized controlled observation was designed.MATERIALS: Totally 50 healthy SD male rates were employed, of clean grade, 6-month old and weighted varied from 290 to 320 g. They were randomized into immobilization group (n=40) and the control (n=10).METHODS: The experiment was performed in Department of Traumatic Surgery in the Hospital affiliated to Medical College of Qingdao University from February 2002 to January 2003. In immobilization group, the right hind-limb of rat was fixed with plaster on the abdomen and the rats were randomized into 4 groups, 10 rats in each, which were sacrificed after abdominal anesthetized on the 1st, 2nd, 4th and 8th weeks successively. The rats in the control group were sacrificed on the 8th week. Except that the immobilization was not applied in the control group, the other managements were same as immobilization group.MAIN OUTCOME MEASURES: Concentrations of GH, IGF-I and somatostation in the tissue extract in rat femurs in the control and on the 1st,2nd, 4th and 8th weeks after immobilization.RESULTS: All the 50 rats were all in result analysis. In immobilization group, GH level on the 8th week was increased remarkably than the control [(41.80±8.39), (19.86±4.21)μg/g, P ＜ 0.05], IGF-I in the femurs reached the peak on the 2nd week, which was higher remarkably than the control [(758.23±23.12), (499.60±18.76)μg/g, P ＜ 0.05], but on the 4th week, it was restored normal as the control and it was decreased remarkably on the 8th week [(258.65±5.76)μg/g, P ＜ 0.05]. Somatostation was higher significantly on the 8th week after immobilization compared with the control [(51.69±2.36), (34.63±8.85)μg/g, P ＜ 0.05].CONCLUSION: GH and IGF-I are not only relevant with bone formation,but also induce the increased concentration of peptides under enhanced bone resorption with immobilization, indicating the possible association with bone resorption.