Effect Of Xenogenous Acelluar Dermal Matrix On Repairing Calvarial Bone Defect Of Rats

Objective:Various bone defects caused by congenital malformations, trauma and tumors have been troubling quantities of patients and medical workers. Currently, bone tissue engineering, as a new interdiscipline, has brought new hope for bone defect repair. Osteoblast-stimulating factor, seed cells and bone scaffolds were three essential elements for bone tissue engineering, among which, scaffold materials played an important role in both cell growth and proliferation and the three-dimensional construction of new tissues. Acelluar dermal matrix membrane (ADM) was a kind of acelluar natural extracellular matrix. Studies indicated that human ADM, which could promote bone regeneration, was a good kind of bone scaffold material. But the lack of sources greatly limited the clinical application of human ADM. Although xenogenous ADM had the similar properties with allogeneic ADM, xenogenous ADM was commonly used as a barrier membrane to guide tissue regeneration and an allograft for soft tissue regeneration, however, xenogenous ADM had been studied rarely to be used as a scaffold for hard tissue regeneration. The aim of this study was to evaluate the effect of acellular dermal matrix membrane, a kind of natural collagen scaffold, on local bone repair in calvarial defects of rats.Methods:Two bilateral fullthickness defects (5mm in diameter) were created in the calvarium of6adult male Wistar rats (200-220g), after which, all left defects were implanted with bovine acellular dermal matrix membrane (Heal-All) and all right defects were left empty to serve as controls. All animals were sacrificed at4weeks after surgery and specimens were prepared for radiologic and histomorphometric analysis. Radiographs of all specimens were obtained to detect the mineral density of new bone and the linear bone healing and the bone area within the defect were measured based on H&E staining. Statistical analysis was performed by means of the paired two-tailed Student t-test.Results:All animals survived successfully after surgery and no obvious inflammation and immunological rejection was found. Specimen observation indicated that the new tissues in bone defect of ADM group were thicker than those of the control group. Compared to the empty defect control group, the ADM group showed a higher bone density (p<0.01). While histological analysis revealed the linear bone healing (p<0.05) and area of new bone (p<0.001) within the defect were significantly better in the ADM group than in the control group, the new bone was more mature in the ADM group than in the control group, which probably resulted from material degradation.Conclusion:The results show that the scaffold has immense potential for bone regeneration indicating favorable biocompatibility, degradability, low immunogenicity, osteoconductive properties and maybe osteoinductive ability, which still requires further studies to confirm.