Study On The Best Time Of Bone Grafting For The Radial Open Bone Defect Of Rabbit Under Seawater Immersion

Objective①To investigate the best time of bone grafting for the radial open bonedefect of rabbit under seawater immersion.②To research the BMP2expressioncharacteristics of open bone defect with seawater immersion during the healing process,and the relationship between osteogenesis and BMP2.Methods①48New Zealand rabbits were randomly divided into0day,3days,7days,14days bone grafting groups, there were12rabbits in each group.15mm completeopen bone defect was made in the middle of all radius, immersed in artificial seawaterfor3hours. Grafted（autologous cancellous bone-ilium） respectively in the same day（0day）or in the3th day,7th day,14th day after modeling. Animals were sacrificed inthe4th,8th,12th week after bone grafting. To observe the healing after autologous bonegrafting for the open bone defect, by imaging observation, histologic observation.②60New Zealand rabbits were randomly divided into ordinary open bone defect group（control group）（n=30）and open bone defect group with seawater immersion（experimental group）（n=30）.15mm transversal open bone defect was made in themiddle of radius, ordinary open bone defect group were exposed in air3hours, openbone defect with seawater immersion group were soaked in seawater for3hours, afterbone grafting with autologous cancellous bone（ilium）, closing the wounds in turn.Rabbits were sacrificed in1,2,3,4,8,12weeks, observed the pathological process、imaging characteristics and BMP-2expression characteristics of open bone defect withseawater immersion after bone grafts during bone healing process in different time. Results①The infection rate of0day bone grafting group was4.17%（1/24）,3daysbone grafting group was29.17%（7/24）,7days bone grafting group was16.67%（4/24）,14days bone grafting group had no infection.②In the8th week after bonegrafting，histopathological examination showed that there were6limbs with new bone，2limbs with chondral at the osteotomy site in0day group；there were4new bone and4ehondral in14days group.③In the8th week after bone grafting, the grayscales ofcallus between the bone defect were194.78±5.86in0day group and183.99±5.97in14days group（P <0.05）.④The second experiment，in the4th week after molding, thegrayscales of callus between the bone defect were146.69±4.37in control group and139.71±3.87in experimental group（P <0.01）; In the8th week, the grayscales of callusbetween the bone defect were201.72±4.91in control group, and194.30±4.65inexperimental group（P <0.01）.Conclusion①The ideal time of treating the radial open bone defect of rabbit underseawater immersion is the one-stage bone grafting.②Seawater delays the BMP2peak expression time and reduces the level of peak expression, and delays the healingprocess of bone defect.