低强度脉冲超声促进骨折愈合的动物实验研究

Accelerating fracture-healing in New Zealand rabbits by low intensity pulsed ultrasounds

目的: 探讨低强度脉冲超声促进骨折愈合的作用。方法: 制备 48只成年新西兰兔双侧桡骨中段骨折模型, 并将实验兔随机分为 6个组。左侧桡骨骨折处应用强度为 30mW/cm2 的低强度脉冲超声体外照射, 每天 1次, 每次 20min, 右侧桡骨骨折处实行假照作为对照。各组实验动物分别于术后 1、2、3、4、5、6周, 采用X线片、骨密度、组织学等指标评价骨折愈合情况。结果: X线片: X线片评分半定量分析表明, 实验侧骨愈合速度明显快于对照侧 (P<0 .05)。组织学: 骨折断端间从纤维连接到骨性连接, 再到骨髓腔再通, 实验侧比对照侧明显提前。骨密度:实验侧BMD在术后 2、3、4周高于对照侧 (P<0. 05), 术后 5、6周二者无明显区别 (P>0. 05)。结论: 低强度脉冲超声通过影响骨折愈合的三个主要阶段—炎症期、愈合期和塑形期而促进骨折愈合。

Objective:To study whether or not low intensity pulsed ultrasounds(LIPUS)could accelerate fracture-healing in New Zealand rabbit radius-fracture model.Method:Forty-eight mature New Zealand rabbits were randomly assigned to 6 groups.The 3mm-long bone defects were made in both radii of each rabbit as fracture model.Exterior LIPUS exposure was made to the left radius -defect with intensity of 30mW/cm^2 for 20 minutes daily.False exposure was made to the right radius-defect as control.X-ray imaging,bone mineral density(BMD),histology were performed to assess the effect of LIPUS at the end of the 1~ st,2~ nd,3~ rd,4~ th,5~ th and 6~ th week postoperatively.Result:X-ray imaging showed callus formation and bone linking in the experimental side were much earlier than that in the control side,indicating that healing in the experimental side were earlier than that in the control side(P<0.05).Histological findings showed that in the experimental side the time needed for changing from fibrous connection to the bony linking of fractures and to rechanellization of bone marrow cavity were earlier than that in the control side.BMD in the experimental side was higher than that in the control side at the end of the 2~ nd,3~ rd and 4~ th week(P<0.05),and no significant difference between both sides at the end of the 5~ th or 6~ th week(P> 0.05).Conclusion:LIPUS accelerates fracture-healing through effects on three main stages of fracture-healing including inflammatory stage,healing stage and remodeling stage.