神经轴突导向分子Semaphorin 3A对骨质疏松模型大鼠骨折愈合的影响

Effect of Semaphorin 3A on fracture healing in osteoporotic rats

目的探讨神经轴突导向分子Semaphorin 3A(Sema3A)对骨质疏松模型大鼠骨折愈合的影响。方法对64只双侧卵巢摘除术后12周的大鼠行单侧胫骨水平切开术,然后将大鼠随机分为对照组和Sema3A组,每组32只。骨切开术后于切开区域每周分别局部注射赋形剂或Sema3A(500μg/kg)。骨折后4、8周收集骨折标本,进行X线、i DXA、组织学、micro-CT检测和三点弯曲实验。结果与对照组相比,Sema3A组骨折后4、8周骨密度、百分比骨体积和骨痂生物学强度均明显增加(P<0.05)。骨折后8周,两组间骨痂相对体积差异无统计学意义(P>0.05),而Sema3A组骨痂平均断面面积较对照组减少(P<0.05)。组织学图像显示Sema3A组骨折后8周骨痂形成和骨化更好。结论 Sema3A治疗骨质疏松模型大鼠骨折4周后能增加骨痂体积和密度,8周后能诱导骨痂骨化和重塑。

Objective To investigate the effect of Semaphorin 3A （Sema3A） on fracture healing in osteoporotic rats. Methods Unilateral horizontal tibial osteotomy was performed on 64 rats 12weeks after bilateral ovariectomy. They were randomly divided into two groups, with 32 rats each. The control group was injected with vehicle in the fracture area and the Sema3A group was injected with Sema3A （500ug/kg）. Specimens were collected 4 and 8 weeks after fracture for X - ray, histology, iDXA, and micro - CT examination, as well as three - point bending test. Results At both d and 8 weeks after fracture, the Sema3A group had higher BMD, BV/TV ratio and biomechanical strength of the callus compared with the control group （P 〈 0. 05）. Eight weeks after fracture, there was no difference in bone volume of callus between the two groups （P 〉 0.05 ）, while the average cross -sectional area of callus in the Sema3A group was lower than that of the control group （P 〈 0. 05 ）. The histology images showed that 8 weeks after fracture, callus formation and callus ossifi- cation of the Sema3A group were better than those of the control group. Conclusion Sema3A treatment for 4 weeks can increase the volume and density of callus, and Sema treatment for 8 weeks can induce callus ossification and remodeling.