胰岛素干预对糖尿病大鼠骨折愈合及骨痂内细胞因子的影响

Insulin effects on fracture healing and cytokines in the osteotylus in experimental diabetic rats

背景:糖尿病是一种以高血糖为特征表现的内分泌代谢紊乱,从而损伤身体多个系统的全身性疾病,并且糖尿病患者骨折后的愈合情况一般都不理想。目的:动态检测胰岛素治疗前后,糖尿病大鼠在骨折愈合过程中细胞因子的变化趋势。方法:SD大鼠120只,随机取90只静脉注射5%四氧嘧啶溶液建立糖尿病大鼠模型;另取30只静脉注射等量的生理盐水做对照。糖尿病大鼠模型随机分为胰岛素治疗组和糖尿病组。将3组大鼠右胫骨中段标准横断骨折,胰岛素治疗组每日胰岛素皮下注射1次,糖尿病组及对照组给予等容量的生理盐水。次日检测大鼠血糖情况;骨折后第1,4,8周拍X射线片观察大鼠骨折的愈合情况;造模后第4,6,8周测定每组大鼠离断后右胫骨骨痂的生物力学强度;免疫组织化学和原位杂交技术检测骨痂内多种细胞因子的表达情况。结果与结论:(1)X射线片结果显示:糖尿病组骨痂形成时间和骨折愈合速度明显低于胰岛素治疗组和对照组,而后2组差异无显著意义;造模后4,6,8周糖尿病组骨折处骨痂的机械强度均明显低于胰岛素治疗组和对照组,而后2组差异无显著意义;(2)骨折后1-4周:骨形态发生蛋白2、碱性成纤维细胞生长因子、转化生长因子、血管内皮生长因子在骨痂中广泛表达,糖尿病组中的表达明显低于和滞于胰岛素治疗组和对照组,而后2组差异无显著性意义;(3)结果表明:糖尿病大鼠骨折愈合过程中较正常大鼠,骨痂形成速度和生物力学强度降低,骨折断处组织细胞的生长因子表达水平明显滞后和下降,运用胰岛素干预治疗后可显著提高骨折部位细胞因子的水平,促进成骨细胞增殖和骨折愈合。

BACKGROUND：Fracture healing in diabetic patients is usual y unsatisfactory because of hormones and metabolic disorder, and an eventual multiple organ dysfunction resulting from high blood glucose. OBJECTIVE：To dynamical y observe the changes of cytokines during the fracture healing process in diabetic rats before and after insulin treatment. METHODS：A total of 120 Sprague-Dawley rats were included in this study. Of them, 90 rats intravenously injected with 5%tetraoxypyrimidine to induce rat models of diabetes were randomized into insulin treatment and diabetes groups, respectively. The remaining 30 rats were intravenously injected with equal volume of saline and selected as control group. The next day, blood glucose was determined. Healing at 1, 4, and 8 weeks after fracture were observed by the X-ray film. Biomechanical strength of the injured right tibia was measured at 4, 6, and 8 weeks after modeling. Cytokines in the osteotylus were determined by immunohistochemical staining and in situ hybridization technique. RESULTS AND CONCLUSION：The X-ray films showed that the speed of fracture healing in the diabetes group was slower than insulin treatment and control groups. Biomechanical strength of the osteotylus in the diabetes group was significantly decreased compared with the insulin treatment and control groups. However, there were no significant differences in above-mentioned parameters between the control and insulin treatment groups. Bone morphogenetic protein 2, basic fibroblast growth factor, transforming growth factor-beta, and vascular endothelial growth factor were widely expressed in the osteotylus and their expressions in diabetes group were significantly lower and slower than those in the control and insulin treatment groups. There was no statistical difference between control and insulin treatment groups. These results indicate that osteotylus formation speed, biomechanical strength, and growth factor expressions at the fracture site in diabetes rats were decreased compared with normal rats. Insulin treatment can enhance cytokine levels at the fracture site, thereby promoting the osteoblast proliferation and fracture healing.