Investigation of the effects of semaphorin 3A on new bone formation in a rat calvarial defect model

J Craniomaxillofac Surg. 2019 Mar;47(3):473-483. doi: 10.1016/j.jcms.2018.12.010. Epub 2018 Dec 20.

Abstract

Purpose: This study investigates the effects of semaphorin 3A on new bone formation in an experimental rat model.

Materials and methods: Cortical bone defects, 5 mm, were created in the calvaria of 40 Wistar rats, which were then separated into three groups: empty defect (control) group, collagen group, collagen + semaphorin 3A group. The bone blocks were harvested after 4 and 8 weeks. New bone formation was assessed by micro-computed tomography (micro-CT), histology, histomorphometry, transmission electron microscope (TEM) and immunohistochemistry.

Results: Increased bone formation was observed in collagen + semaphorin 3A groups both histologically and with micro-CT. In the histomorphometic analysis, the control group had significantly less bone formation compared to both the collagen and collagen + semaphorin 3A group at 4 weeks (p = 0.0001) and 8 weeks (p = 0.0001). The collagen group had significantly less bone formation compared to collagen + semaphorin 3A group both at 4 weeks (p = 0.002) and 8 weeks (p = 0.005). Immunohistochemical analysis revealed that semaphorin 3A inhibited receptor activator of nuclear factor-kB ligand (RANKL) expression and increased the expressions of osteoblastic bone markers at 4 weeks. In TEM analysis, the collagen + semaphorin 3A group had an increased proliferation and bone formation rate at 4 weeks, whereas bone quantity and maturation were enhanced at 8 weeks.

Conclusion: Locally applied semaphorin 3A increases callus formation at 4 weeks and bone formation at 8 weeks. Semaphorin 3A prevents bone resorption by inhibiting osteoclasts and increases bone formation by inducing osteoblasts.

Keywords: Bone regeneration; Calvarial bone defect; Semaphorin 3A.

MeSH terms

  • Animals
  • Bone Regeneration / drug effects*
  • Bone Regeneration / physiology
  • Collagen
  • Disease Models, Animal
  • Drug Carriers
  • Male
  • Microscopy, Electron, Transmission
  • Osteoblasts / drug effects*
  • Osteoblasts / physiology
  • Osteoclasts / drug effects*
  • Osteoclasts / physiology
  • Random Allocation
  • Rats
  • Rats, Wistar
  • Semaphorin-3A / pharmacology*
  • Skull / cytology
  • Skull / diagnostic imaging
  • Skull / drug effects*
  • Skull / ultrastructure
  • X-Ray Microtomography

Substances

  • Drug Carriers
  • Semaphorin-3A
  • Collagen