Objective The objective of this study was to investigate whether postoperative rapping by external axial stress stimulator can accelerate rabbit tibial fracture union by analyzing the expression of vascular endothelial growth factors (VEGF),CD34,bone morphogenetic protein-2 (BMP-2) and transforming growth factor-β1 (TGF-β1) in different periods osteotylus.Methods New Zealand rabbit tibial fracture models were randomly divided into two groups.Experimental group received stress stimulation for 30 minutes every two days began at postoperative 8 days.Lane-Sandhu X-ray evaluation system was used to evaluate the bone healing process at 2,4,6 and 8 weeks.Specimens (n =6) were obtained for immunohistochemical test and semi quantitative analysis to compare the expression of VEGF,CD34,BMP-2 and TGF-β1 at postoperative 2,4,6 and 8 weeks.Results (1) The mean Lane-Sandhu X-ray score in experimental group was significantly higher than controlled group with more osteotylus quantity at 4,6 and 8 weeks.At 4,6,8 weeks postoperation,the score of experimental group (5.33 ± 0.54,7.00 ± 0.82,9.67 ±0.47) was significantly higher than the control group (3.67 ±0.15,5.67 ±0.44,7.08 ±0.32,P ＜0.05).(2) The VEGF in the experimental group reached the peak at 4th week after operation,the density (mean) in the experimental group was (532.50 ± 13.50) higher than that in the control group (319.18 ± 12.09),P ＜ 0.05;BMP-2 peaked at the 6th week after operation and the density (mean) of the experimental group was reached.(571.79 ±7.97) was higher than that of the control group (296.10 ± 12.99,P＜0.01).CD34 peaked at the 4th week after operation,the density (mean) in the experimental group was (451.69 ±40.94) higher than that in the control group (252.65 ± 14.49,P ＜0.01);TGF-β1 peaked at the 4th week too,the density (mean) in the experimental group was (433.78 ±3.41) higher than that in the control group (249.41 ± 12.03,P ＜ 0.01).Conclusion Postoperative rapping by external axial stress stimulator can promote the expression of VEGF,CD34,BMP-2 and TGF-β1,stimulate vascularization and osteogenesis in the fracture site of rabbit tibia,therefore,accelerate the fracture union.%目的 探讨体外轴向应力刺激对骨折愈合过程中不同时间点血管内皮生长因子(VEGF)、CD34分子(CD34)、骨形态发生蛋白-2(BMP-2)及转化生长因子-β1(TGF-β1)表达的影响.方法 制作新西兰大白兔胫骨骨折模型,随机分为实验组和对照组,实验组术后第8天开始每两天给予应力刺激1次,每次30 min,对照组为无体外轴向应力治疗组.术后第2、4、6、8周行X线检查并用Lane-Sandhu评分标准评估骨折愈合程度,并于各时间点取材组织学(n=6)染色并进行半定量分析比较两组标本VEGF、CD34、BMP-2及TGF-β1的表达.结果 X线片显示术后4、6、8周实验组骨痂量均较对照组好,实验组X线Lane-Sandhu评分[(5.33±0.54)、(7.00±0.82)、(9.67±0.47)分]明显高于对照组[(3.67±0.15)、(5.67±0.44)、(7.08 ±0.32)分],差异均有统计学意义(P＜0.05);术后第4周实验组VEGF达到高峰,平均吸光度值(532.50±13.50)高于对照组(319.18±12.09),差异有统计学意义(P＜0.05);术后第6周BMP-2达到高峰,实验组平均吸光度值(571.79±7.97)高于对照组(296.10±12.99),差异有统计学意义(P＜0.01);CD34在术后第4周达到高峰,实验组平均吸光度值(451.69±40.94)高于对照组(252.65±14.49),差异有统计学意义(P ＜0.01);TGF-β1在术后第4周达到高峰,实验组平均吸光度值(433.78±3.41)高于对照组(249.41±12.03),差异有统计学意义(P＜0.01),且CD34和TGF-β1在术后第6、8周两组差异无统计学意义.结论 体外轴向应力刺激治疗可以促进兔胫骨骨折部位VEGF、CD34、BMP-2和TGF-β1的表达,促进骨断端血管化及刺激成骨,从而促进骨折愈合.
展开▼
