Expression of bone morphogenetic protein 2 in rabbit radial defect site with different lengths.

BACKGROUND It has been studied that the distribution of bone morphogenetic protein 2 is regular under bone defect situation. OBJECTIVE To observe the expression of bone morphogenetic protein 2 in rabbit radial defect site with different lengths. METHODS Forty-eight New Zealand rabbits were divided into two groups randomly. 0.5 cm bone defect and 3.0 cm bone defect were made by wire saw at the middle part of radius bone after anaesthesia. RESULTS AND CONCLUSIONS Western blot results showed that in the 0.5 cm bone defect group, the expression of bone morphogenetic protein 2 of the tissues in the bone defect site was increased gradually at 1, 3, 4 weeks after operation, and the expression in each defect group was increased when compared with that immediately after injury (P<0.05). In the 3.0 cm bone defect group, the expression of bone morphogenetic protein 2 of tissues in bone defect site was increased gradually and reached to its peak at 3 weeks after the operation (P<0.05). The peak value in the 3.0 cm bone defect group was significantly higher than that in 0.5 cm bone defect group (P<0.05). The peak value was maintained in high level. The comparison of bone callus formation showed that the bone callus formation of 3.0 cm bone defect group was less than that of the 0.5 cm bone defect group at 3 and 4 weeks after operation (P<0.05). The results indicate that expression of the bone morphogenetic protein 2 in 3.0 cm bone defect site is increased significantly, but the expression level cannot make the bone defect heal itself.