Experiment Study Of Guiding Rabbit Radii Bone Tissue Regeneration By Frozen Heterogeneous Periosteum

Objective:Explores the feasibility of guiding bone tissue regeneration by frozen heterogeneous periosteum,and to explore the mechanism of the membrane guided bone regeneration(MGBR),to investigate the healing mechanisms of massive allogenic cortical transplants and the clinical significance。Methods:The animal models of bony and periosteous defects were established in both radii of 30 adult New Zealand white rabbits.Experiment side is wrapped with defatted frozen fresh pig periosteum,and control side is not wrapped,which is used as comparison.Evaluate healing situation of the 30rabbits' radii bony defect with the methods of X-ray examinations,general observation,histological observation and biomechanical examination.Results:1)X-ray examinations:Experiment side.4weeks after operation,batt-shaped ossification appears in the defect center;Six weeks later,higher density bony callus is formed in the bone defect area;8weeks later,continuous bony callus is formed,and cortex-bone appears as well;12 weeks later,the bony defect basically heals,whose density is similar to the host bone.There is no transparent area.The neonatal radii is slim and it's outline has basically recovered. Control side.4weeks after the operation,bony callus mainly centralizes at the both fragments,and most of the area is transparent;Six weeks later,no more bony callus appears,and no batt-shaped ossification in the center;8 weeks later,no obvious continuous bony callus and no cortex-bone appear,and the both fragments density increases;12 weeks later,not a sigle case heals,transparent-area is still available,the both fragments density is high,and sclerotic is formed.2)General observation:Two weeks later,the experimental transplanted periosteum's outline is complete.Parenchyma around the bony defect is blocked out,while the comparative bony defect has meatbud tissue.4weeks later,a small amount of bony callus exists in the experimental membrane tube,whose shape is taper,and it keeps growing.The opposite has a large amount of growing meatbud tissue,no tuper bony callus.6weeks later,the experimental centrality grows obviously,and the bone becomes harder.the opposite's bony callus begins to sclerotic,compared with no obvious;centrality and much connective tissue.8 weeks later,the experimental side has new bones,which has reached the center and nearly connected but the rigidity is not as good.The opposite sclerosis,marrow antrum shuts up,and the tissue softens.12 weeks later,the experimental side has healed,but the opposite has failed.3)Histological observation.Experiment side:2weeks later,the transplanted periosteum is complete,and there is clotted blood,whose fibre albumen is solid reticulation,and neonatal blood vessel and nerve fibre can be seen.4weeks later,the periosteum is complete,neonatal bone has formed and it is active. Large amounts of fibre bone-scab have filled up the defect center.6 weeks later,the transplanted periosteum begins to fade out,much neonatal bone takes the place,which osteoblasts and osteoclasts are around,no inflammation available.8 weeks later,remaining periosteum still be seen,neonatal bone is in good order,and marrow antrum begins to form.12 weeks later,the transplanted periosteum has almost been replaced by the neonatal mature ones.Marrow antrum has been formed up.Control side2 weeks later,a small amount of bony callus appears around the both fragments,cartilage appears,and fibre meatbud tissue grows into the center of bony defect.From 4 to 6weeks after the operation,cartilage begins to fade,meatbud tissue changes into fibrous tissue,and sclerotic phenomenon can be seen.From 8 to 12 weeks,the both fragments is slim,many cartilage and tissue can still be seen in the center,marrow antrum is shut off by cortex bones,and the defect area is filled with many fibrous tissues.Conclusion:(1)Frozen heterogeneous periosteum can be stored in the body for 8-12weeks.No repellent phenomenon appears,and it has good tissue commutative crasis.(2)Frozen heterogeneous periosteum can prevent the nearby fibrous tissue from growing into the bony defect,making the healing rate increase greatly,so it can be used as material to guide bone regeneration;and it has a good effect.(3)The dealt-with heterogeneous periosteum has the function of mechanicalobstacle,abduction and conduct.It protects and stablilizes hematoma,maintains the exietance of periosteum space and promotes the reproduction of boney circular system.