Effectiveness Evaluation Of Two Bone Repair Materials Using Critical Size Bone Defect

Background: Bone defect is a typical orthopedic disease,which may be caused by severe trauma,virus infection,cancer or congenital musculoskeletal diseases.Because the application of autogenous bone and allogenic bone in repairing bone defects is limited,artificial bone graft materials have become the focus of research and development.Despite the emergence of many artificial bone graft materials,the repair ability of these materials for bone defects is still limited compared with autogenous bone,allograft bone and xenograft bone,and the repair effect is difficult to meet expectations in all aspects.Therefore,in order to meet the clinical application,in this study,the Collagen-based bone repair material made of collagen and hydroxyapatite were evaluated.Objective: Evaluate biocompatibility of collagen-based bone repair material and using the animal model with critical size bone defect to evaluate bone repair capacity of collagen-based bone repair material by comparing with that of Calcium Phosphate Bio ceramic Bone Repair Materials.Methods: Biocompatibility evaluation of bone repair materials: Selected appropriate bone repair material sand evaluated their cytotoxicity,intradermal reaction and skin sensitization before animal study.Evaluation of repair effect of bone repair materials: Animals were divided into test group,control group and blank control group.A 1.5cm bone defect was made on one side of radius of each animal.The animals in the test group were repaired with collagenbased bone repair material,the animals in the control group were repaired with Calcium Phosphate Bio Ceramic Bone Repair Material,and the animals in the blank control group received no repair materials.Evaluation was performed for some animals in each group at 4 weeks,8 weeks and 12 weeks after surgery.The endpoints of bone repair effect include medical imageology and histopathology.The endpoints of systemic toxicity include hematological and blood biochemical examination,daily cage side observation,gross pathological examination and histopathological examination.Results: The cytotoxicity test results showed that the survival rate of collagenbased bone repair material(test group)after 24 hours of contact with cells was 93.01%with 100% MEM extract,while the survival rate of Calcium Phosphate Bio Ceramic Bone Repair Material(control group)after 24 hours of contact with cells with 100%MEM extract was 98.17%,The results of both materials were higher than 70% in intradermal response test.The results showed that the primary stimulation index of both polar and nonpolar extracts of collagen-based bone repair material(test group)and Calcium Phosphate Bio Ceramic Bone Repair Material(control group)were 0.0;The skin sensitization test results showed that the skin sensitization scores of both polar and nonpolar extracts of collagen-based bone repair material(test group)and Calcium Phosphate Bio Ceramic Bone Repair Material(control group)were 0.0;After implanting collagen-based bone repair material(test group)and Calcium Phosphate Bio Ceramic Bone Repair Material(control group)into a rabbit bone defect model for 4,8,and 12 weeks,X-ray imaging results showed that the bone defect underwent a process of callus formation,cortical connection,and medullary cavity recanalization.The test group scored higher in bone formation,bone connection,and bone remodeling than the control group in each cycle,And the experimental and control groups were significantly better than the blank control group;The blood test showed that the blood indicators of the experimental group,the control group,and the blank control group animals were within the normal range during each observation period,and there was no statistical difference between pre-operation and pre-execution.The cage-side observation showed that all experimental animals had no abnormal non-toxic reaction during the feeding period.The gross pathological examination results showed that the naked eye observation results showed that all organs were normal without abnormal changes.The gross pathological examination results of the implanted site showed that the macroscopic observation results showed no reaction such as wound infection,tissue necrosis,tissue effusion,and suppuration.The histopathological examination results of experimental animals showed that there was no visible damage to the main organs(including heart,liver,spleen,lung,and kidney)of animals in different cycles in all groups.Histopathological examination of the implant site and HE staining results showed that bone tissue sections showed that the bone defect underwent a process of massive bone trabecular formation,bone trabecular growth,dense bone formation,and bone marrow cavity recanalization.The bone growth in the experimental group was better than that in the control group,but both were significantly better than those in the blank control group.MASSON staining results showed that the bone defect part experienced the process of new bone formation and the transformation of new bone to mature bone tissue.The bone growth of the test group was better than that of the control group,but both were significantly better than that of the blank control group.Conclusion: The collagen-based bone repair material has a good biocompatibility and will not have negative effects on tissues;As a composite material,compared with the Calcium Phosphate Bio Ceramic Bone Repair Material,it has better repair effect of bone defect.