Effect of Semaphorin 3A on fracture healing in osteoporotic rats

QU Mo-yuan; HU Jing; LI Yun-feng

Abstract：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 (500μg/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 4 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.