胰岛素样生长因子1在糖尿病骨折大鼠骨痂组织中对成骨细胞增殖和骨钙素表达的影响

Effect of insulin-like growth factor 1 on osteoblast proliferation and osteocalcin expression in osteotylus of diabetic rats after fracture

背景:有研究表明,糖尿病患者骨折愈合过程中局部骨痂组织胰岛素样生长因子1明显降低,成骨细胞增殖能力下降。目的:观察以胰岛素样生长因子1治疗糖尿病大鼠骨折愈合过程中骨痂组织成骨细胞增殖和骨钙素表达,分析胰岛素样生长因子1在糖尿病大鼠骨折愈合过程中的作用。设计、时间及地点:随机对照动物实验,于2008-09/12在昆明医学院动物实验中心完成。材料:40只SD雄性大鼠,30只腹腔内注射链脲佐菌素破坏胰岛细胞诱导为糖尿病大鼠后,随机分为胰岛素样生长因子1组、胰岛素组、模型对照组,10只为正常对照大鼠,腹腔内注射等容量生理盐水。方法:4组大鼠右胫骨上段骨折后,胰岛素样生长因子1组用胰岛素样生长因子1治疗,30μg/kg,胰岛素组用胰岛素治疗,6～8U,模型对照组及正常对照组未进行治疗。主要观察指标:伤后第1,2,4,6周X射线片观察骨折愈合情况,光镜下观察骨痂内成骨细胞数量,免疫组织化学测定血清骨钙素表达。结果:胰岛素样生长因子1组、胰岛素组X射线片显示骨痂生成量多,骨折愈合程度明显优于模型对照组(P<0.05),胰岛素样生长因子1组、胰岛素组差异无显著性意义。光镜观察显示,胰岛素样生长因子1组、胰岛素组成骨细胞数量明显多于模型对照组,但低于正常对照组。各组血清骨钙素均呈上升趋势,在第2周达到峰值,第4周下降,至第6周进一步下降。模型对照组骨钙素升高幅度明显低于正常对照组(P<0.01),并且低于胰岛素样生长因子1组、胰岛素组。胰岛素样生长因子1组、胰岛素组、正常对照组的骨钙素差异无显著性意义。结论:糖尿病大鼠骨折愈合过程中,用胰岛素样生长因子1治疗可提高骨钙素水平,促进成骨细胞增殖,与胰岛素治疗效果相当。

BACKGROUND： Previous studies demonstrated that local expression of insulin-like growth factor 1 （IGF-1） is obvious decreased accompanied by inadequate osteoblast proliferation in osteotylus of diabetic patients after fracture. OBJECTIVE： To observe the osteoblast proliferation and osteocalcin expression in healing of fractures in rats with diabetes induced by IG]F-1, in addition, to analyze the effect of IGF-1 on fracture healing. DESIGN, TIME AND SETTING： The Randomized controlled animal experiment was performed at the Animal Center of Kunming Medical College between September and December 2008. MATERIALS： Forty male Sprague Dawley rats, 30 of them were induced into diabetic rats by intraperitoneal injected streptozotocin, and randomly divided into the IGF-1, insulin, and model control groups, and the remained 10 rats, which were injected with same volume of normal saline, were served as the normal control group. METHODS： After all the right tibiae were broken, 30 μ g/kg IGF-1 or 6-8 U insulin was used in the IGF-1 and insulin groups respectively. There was no treatment in the model control and normal control groups. MAIN OUTCOME MEASURES： Fracture healing was observed by X-ray, population of osteoblasts was overviewed by light microscope, and serum osteocalcin expression was measured by immunohistochemistry at the weeks 1, 2, 4, and 6 after operation. RESULTS： The X-ray film showed that the amount of callus was larger in the IGF-1 group. The fracture healing was better than the model control group （P 〈 0.05）. There was no statistical difference between the IGF-1 and the insulin groups. The population of osteoblasts was greater in the IGF-1 group and insulin group than that of the model control group, but lower than the normal control group. The level of serum osteocalcin was elevated in all groups, peaked at 2 weeks, and then decreased at 6 weeks, which further decreased at 6 weeks. The increasing amplitude of serum osteocalcin in the model control group was notably smaller than the normal control group （P 〈 0.01 ）, meantime, lower than IGF-1 and insulin groups. The osteocalcin level had no statistical significance between the IGF-1, insulin and normal control groups. CONCLUSION： During the healing of fractures in rats with diabetes, IGF-1 can reach equivalent effect as insulin treatment by elevating osteocalcin levels, and accelerating osteoblast proliferation.