Acceleration of segmental bone regeneration in a rabbit model by strontium-doped calcium polyphosphate scaffold through stimulating VEGF and bFGF secretion from osteoblasts

Abstract Background: Bone grafting is commonly used for reconstructing skeletal defects in the craniofacial region. Several bone augmentation models were developed to optimize bone regeneration in both vertical and horizontal dimesions. Aim: The aim of this study was to develop a surgical animal model for establishing a three-dimensional (3D) grafting environment in the animal's mandibular ramus for horizontal and vertical bone regeneration using osseous shell technique, as in human patients. Materials and methods: Initial osteological and imaging survey were performed on a postmortem skull of a New Zealand White (NZW) rabbit skull, Oryctolagus cuniculus, for feasibility assessment for performing the surgical procedure. 3D osseus defect was created in the mandibular ramus through a submandibular incision and the osseous shell plates were stabilized with osteosynthesis fixation screws and defect filled with particular bone grafting material. The in-vivo surgical procedures were conducted in four 8-week-old NZW rabbits utilising two osseous shell materials: xenogenic human cortical plates, and autogenous rabbit cortical plates, and the created 3D defects were filled using xenograft and allograft bone grafting materials. The healed defects were evaluated for bone regeneration after 12 weeks using histological and Cone Beam Computed Tomography (CBCT) imaging analysis. Results: Clinical analysis at 12 weeks after surgery revealed the stability of the 3D grafted bone augmentation defects using the osseous shell technique. Imaging and histological analyses confirmed the effectiveness of this model in assessing bone regeneration. Conclusion: The rabbit model is an efficient and reliable biological method for creating a seizable three-dimensional horizontal and vertical bone regeneration model in the mandibular ramus using osseous shell technique for testing various bone-substitute materials testing without compromising the health of the animal. The filled defects could be analyzed for osteogenesis, quantification of bone formation, and healing potential, using histomorphometric analysis, in addition to 3D morphologic evaluation using radiation imaging.

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Ultraviolet-Crosslinkable and Injectable Chitosan/Hydroxyapatite Hybrid Hydrogel for Critical Size Calvarial Defect Repair In Vivo

Journal of Nanotechnology in Engineering and Medicine ◽

10.1115/1.4032902 ◽

2015 ◽

Vol 6 (4) ◽

Cited By ~ 3

Author(s):

Baoqiang Li ◽

Lei Wang ◽

Yu Hao ◽

Daqing Wei ◽

Ying Li ◽

...

Keyword(s):

Bone Regeneration ◽

Critical Size ◽

Rabbit Model ◽

Single Step ◽

Calvarial Defect ◽

Defect Model ◽

Calvarial Bone ◽

Hybrid Hydrogel ◽

Defect Site

To promote bone regeneration in vivo using critical-size calvarial defect model, hybrid hydrogel was prepared by mixing chitosan with hydroxyapatite (HA) and ultraviolet (UV) irradiation in situ. The hydrosoluble, UV-crosslinkable and injectable N-methacryloyl chitosan (N-MAC) was synthesized via single-step N-acylation reaction. The chemical structure was confirmed by 1H-NMR and FTIR spectroscopy. N-MAC hydrogel presented a microporous structure with pore sizes ranging from 10 to 60 μm. Approximately 80% cell viability of N-MAC hydrogel against encapsulated 3T3 cell indicated that N-MAC is an emerging candidate for mimicking native extracellular matrix (ECM). N-MAC hydrogel hybridized with HA was used to accelerate regeneration of calvarial bone using rabbit model. The effects of hybrid hydrogels to promote bone regeneration were evaluated using critical size calvarial bone defect model. The healing effects of injectable hydrogels with/without HA for bone regeneration were investigated by analyzing X-ray image after 4 or 6 weeks. The results showed that the regenerated new bone for N-MAC 100 was significantly greater than N-MAC without HA and untreated controls. The higher HA content in N-MAC/HA hybrid hydrogel benefited the acceleration of bone regeneration. About 50% closure of defect site after 6 weeks postimplantation demonstrated potent osteoinductivity of N-MAC 100 UV-crosslinkable and injectable N-MAC/HA hybrid hydrogel would allow serving as a promising biomaterial for bone regeneration using the critical-size calvarial defect.

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