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Histopathological features of bone regeneration in a canine segmental ulnar defect model

Rahim Hobbenaghi1, Pariya Mahboob2, Siamak Saifzadeh3, Javad Javanbakht4*, Javad Yaghoobi Yeganeh Manesh5, Rasool Mortezaee6, Seyed Rashid Touni7, Ehsan Hosseini8, Shahin Aghajanshakeri9, Milad Moloudizargari9 and Soheil Javaherypour9

Author Affiliations

1 Department of Pathology, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran

2 Graduate, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran

3 Institute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, Brisbane Qld 4059, Australia

4 Department of Pathobiology, Faculty of Veterinary Medicine, Tehran University, Tehran, Iran

5 Gradute of Islamic Azad University of Shahrekord, Faculty of Veterinary Medicine, Shahrekord University, Shahrekord, Iran

6 Student of Ferdowsi University of Mashhad, Faculty of Veterinary Medicine, Ferdowsi University, Mashahd, Iran

7 Ph.D Student of Anatomy and Embryology, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran

8 Faculty of Para Veterinary Medicine, Ilam University, Ilam, Iran

9 Student of Veterinary Medicine, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran

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Diagnostic Pathology 2014, 9:59  doi:10.1186/1746-1596-9-59

Published: 17 March 2014



Today, finding an ideal biomaterial to treat the large bone defects, delayed unions and non-unions remains a challenge for orthopaedic surgeions and researchers. Several studies have been carried out on the subject of bone regeneration, each having its own advantages. The present study has been designed in vivo to evaluate the effects of cellular auto-transplantation of tail vertebrae on healing of experimental critical bone defect in a dog model.


Six indigenous breeds of dog with 32 ± 3.6 kg average weight from both sexes (5 males and 1 female) received bilateral critical-sized ulnar segmental defects. After determining the health condition, divided to 2 groups: The Group I were kept as control I (n = 1) while in Group II (experimental group; n = 5) bioactive bone implants were inserted. The defects were implanted with either autogeneic coccygeal bone grafts in dogs with 3-4 cm diaphyseal defects in the ulna. Defects were stabilized with internal plate fixation, and the control defects were not stabilized. Animals were euthanized at 16 weeks and analyzed by histopathology.


Histological evaluation of this new bone at sixteen weeks postoperatively revealed primarily lamellar bone, with the formation of new cortices and normal-appearing marrow elements. And also reformation cortical compartment and reconstitution of marrow space were observed at the graft-host interface together with graft resorption and necrosis responses. Finally, our data were consistent with the osteoconducting function of the tail autograft.


Our results suggested that the tail vertebrae autograft seemed to be a new source of autogenous cortical bone in order to supporting segmental long bone defects in dogs. Furthermore, cellular autotransplantation was found to be a successful replacement for the tail vertebrae allograft bone at 3-4 cm segmental defects in the canine mid- ulna. Clinical application using graft expanders or bone autotransplantation should be used carefully and requires further investigation.

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Bone defect; Bone regeneration; Vascular bone grafting; Histopathology; Dog