ALLOGRAFT BONE APPLICATION IN THE RAT CALVARIAL BONE DEFECT MODEL: A HISTOPATHOLOGICAL STUDY

Trauma, neoplasms, infections, and congenital anomalies may be the reason for the calvarial bone defects. For eliminating bone defects in the cranial region to stimulate bone regeneration different graft types have been tried. In our study, we aimed to investigate the effects of allograft application in the rat calvarial bone defect model. For this purpose, 14 Wistar male rats were determined; defect (n=7) and defect + graft (n=7) groups. . The frontal bone was opened and a circular full thickness bone defect (5 mm) was created in the midline. Allograft material was placed in the defect area. All animals were sacriced after 28 days and the calvarial bones were followed up for routine histologic preparations. Sections were stained with H-E and scoring for histopathological parameters (inammation, brosis, osteoclast number, osteoblast number, osteocyte number, matrix formation, new bone trabecular diameter). In our study, inammation, brosis and osteoclast numbers decreased in the defect + graft group compared to the defect group, and osteocyte, osteoblast, matrix formation and bone trabecular diameter has increased signicantly. Histopathological evaluation revealed scar tissue, increased mononuclear cell inltration, and necrosis in the defect group. In the defect + graft group, an increase in collagen ber, a decrease in inammatory cells, an increase in osteoblast cells and bone matrix were observed. As a result, allograft application has been found to support new bone formation in the calvarial defect model by creating an osteoinductive and osteoconductive effect.

Download Full-text

In Vitro Prevascularization of Self-Assembled Human Bone-Like Tissues and Preclinical Assessment Using a Rat Calvarial Bone Defect Model

Materials ◽

10.3390/ma14082023 ◽

2021 ◽

Vol 14 (8) ◽

pp. 2023

Author(s):

Fabien Kawecki ◽

Todd Galbraith ◽

William P. Clafshenkel ◽

Michel Fortin ◽

François A. Auger ◽

...

Keyword(s):

Bone Defect ◽

Bone Repair ◽

Human Bone ◽

Male Rats ◽

Defect Model ◽

Calvarial Bone ◽

Calvarial Bone Defect ◽

Self Assembled

In vitro prevascularization has the potential to address the challenge of maintaining cell viability at the core of engineered constructs, such as bone substitutes, and to improve the survival of tissue grafts by allowing quicker anastomosis to the host microvasculature. The self-assembly approach of tissue engineering allows the production of biomimetic bone-like tissue constructs including extracellular matrix and living human adipose-derived stromal/stem cells (hASCs) induced towards osteogenic differentiation. We hypothesized that the addition of endothelial cells could improve osteogenesis and biomineralization during the production of self-assembled human bone-like tissues using hASCs. Additionally, we postulated that these prevascularized constructs would consequently improve graft survival and bone repair of rat calvarial bone defects. This study shows that a dense capillary network spontaneously formed in vitro during tissue biofabrication after two weeks of maturation. Despite reductions in osteocalcin levels and hydroxyapatite formation in vitro in prevascularized bone-like tissues (35 days of culture), in vivo imaging of prevascularized constructs showed an improvement in cell survival without impeding bone healing after 12 weeks of implantation in a calvarial bone defect model (immunocompromised male rats), compared to their stromal counterparts. Globally, these findings establish our ability to engineer prevascularized bone-like tissues with improved functional properties.

Download Full-text