The Experimental Study Of ARBM And Its Different Components Mixed With PCPC To Repair Bone Defects In Rabbit Radius

Objective: To investigate the effect of autologous red bone marrow （ARBM） and itsdifferent components in complex porous calcium phosphate cement （PCPC） on thetreatment of rabbit radial defect, to find the major components of ARBM in thehealing of bone defects which play a catalytic role in the composition. Through thestudy to provide experimental evidence in treatment of bone defect for clinical work.Methods: Select40healthy New Zealand white rabbits, regardless male and female,with body weight of2.5-3.0kg. All animals were performed experimental model of1.5cm bone defect in bilateral radius, The80forelimbs were randomly divided into A,B, C, D and E five groups, each group contained16sides. E group was the controlgroup. And then the region of these bone defects were implanted with correspondingcomposites: group A was implanted with ARBM/PCPC, group B was implanted withBMMNC/PCPC, group C was implanted with bone marrow of no cellular componentfluid/PCPC, group D was implanted with bone marrow removing the supernatantcells/PCPC, group E was implanted with PCPC only. At the4^th_,8^th_,12^th_weekafter operation, four rabbits were selected randomly from each group at each timepoint（Two rabbits were sacrificed; Two rabbits were anesthetized） and examined byX-ray. Among the four rabbits in each group,the two sacrifice rabbits were executedby biomechanical test and histological observation, and observed the bone formationin different periods. The specimen X-ray was scored according to the modified Lane- Sandhu X-ray rating criteria, and the results were performed statistical analysis.Results:1:The gross dissection showed at12^th_week, the bone defects werecompletely repaired in group C, and the marrow cavity refunctioning could be seen.The bone defects were gross repaired in groups B and D. There was large callusformation in group C. There only part new bone formation in the group E,and thebone defects were not repaired.2: At4^th week, the X-ray showed that in the group A, the osteotomies linewere vague in implant sides, more callus formation which crossing fracture line andsurround the implant. In groups B, C and D, a small amount of callus formation, andthe callus mainly exists in the osteotomies terminal and beside ulna. There was noobvious callus formation in group E and osteotomies lines are clear. At8^th week,theX-ray showed that in the group A, there was a large number of callus formation. Thegap of osteotomies surface disappear and the shadow of bone sclerosis could be seennear the ulna. There were more callus formation than the former in groups B, C and D,and osteotomies lines are fuzzy. Callus in group B and group D were more than thosein group C. The outline of implant are visible. There were small amount of callusformation of osteotomies in group E, the osteotomies line are clearly andintramedullary were closed. At12^th week,the X-ray showed that in group A, theimplant and the end of osteotomies are fusion, new bone cortex formation andsmooth, part of intramedullary reascularization could be seen and the bone defect arerepaired. The bone defect in group B, C and D were grossly repaired, amount of callussurroun implant and the shadow of bone sclerosis near the ulna could be seen, Therewere no obvious bony cortex and intramedullary reascularization. In group E, intra-medullary are closed and bone defect are not repaired.3: At4^th week, the histological examination showed that in group A, the obvious hyperplasia of cartilage cells could be seen, and bone cells, bone trabeculae,bone matrix are formation, its present flake or island shape. In groups B, C and D,there were more bone trabeculae and bone matrix formation, and their structure arerelatively matured. In Group E, the fibrous tissue, necrotic tissue and a small amountof cartilage cells formation in the ends of artificial could be seen. at8^th week, in groupA, more mature bone trabeculae formation could be seen and the most part of wovenbone transform to shelf bone in which a number of mature osteoblast, asteoclast,osteocyte and bone matrix formation. In group B, C and D, a small amount of shelfbone formation could also be seen. In group E, there were more cartilage cellsformation than former and a small amount of trabecula formation. At12^th week, ingroup A, the trabecula are permutating in order and which are showing lamellar,medullary space are cutthrough, mature harvard system, woven bone are rebuilding toshelf bone. In group B, C and D, there were more shelf bone formation than former,but could not be seen medullary space are obvious recanalisation; In group E, therewere only a small amount of shelf bone formation.Conclusion:1: PCPC can be used as scaffolds materials in bone tissue engineering.Both cell components of ARBM and growth factors in supernatantfluid of ARBM can promote bone defect repair.2: Cell component of ARBM and the supernatant fluid of ARBM havea synergistic effect in promoting bone growth.3: ARBM can be used in the treatment of bone defect, and the majorcomponents of ARBM in promoting bone defect repair are existed inBMMNC.