BMP-2 activity in the local tissue of rabbit radial defect and its relationship with bone healing

Objective To establish an objective animal experimental model for the experimental study of clinical bone defect,detect the BMP-2 activity in bone defect area,and observe the early healing situation of rabbit radial fracture.Methods A total of 72 New Zealand rabbits [weight/ each:(2.8 ±0.2)kg] were randomly divided into four experimental groups A,B,C,and D (18/each) with corresponding 0.5 cm,1.5 cm,2.0 cm,and 3.0 cm bone defect models abolished,respectively,in the middle of the rabbit left radius.By the time of modeling,all the bone segments were retained and a small amount of bone adjacent tissues were taken as E specimens of control group.Modeling time was recorded as 0 week,and six animals of each group were killed in 1 W,3 W,4 W later.Then the bone defect surrounding tissues were taken to check BMP-2 content by Western-blot detection,and the bone-healing situation was observed at different time.Results BMP-2 composition showed a significant increase in secretory volume of each group's bone defect area tissues after modeling one week,compared with E specimens of control group (P ＜ 0.05).BMP-2 composition secretion capacity even reached its peak in the third week four groups (A,B,C,D)increased by 556.1％,385.9％,272.2％,171.2％ respectively.and BMP-2 content reduced apparently in the fourth week than before(P ＜ 0.05).At the same time,BMP-2 content decreased with the addition of bone defect length(P ＜ 0.05).Also a correlation was shown between bone healing and time with the bone defect length.Conclusions A comparable rabbit radial bone defect model was successfully established.These objective animal models,which are closer to clinical reality,provide the theoretical basis of animal experiments to explore the mechanism of human fracture healing. Key words: Fracture healing;  Disease models, animal ;  Radius fractures ;  Bone morphogenetic proteins/biosynthesis