An experimental study of bone defects repaired with bone morphogenetic protein using polylactic acid as carrier / 中华骨科杂志

ABSTRACT

Objective To study the feasibility of polylactic acid(PLA) as carrier of bone morphogenetic protein(BMP), and observe its results of inducing osteogenesis. Methods A 12 mm bone defect experimental model in the left ulna of rabbits was made, the animals were divided into three groups at random, bovine BMP 10 mg with PLA carrier was implanted into the defect area in the experimental group, bovine BMP 10 mg with bovine cancellous bone matrix carrier was implanted in the control group, and nothing was implanted in the blank group. The osteogenesis of the bone in the defect area was observed by regular roentgenography, the histological changes of the bone defect tissue in 4th, 8th, 12th week after operation were studied and the new bone formation was measured by image analysis. Results The results revealed that the bone defect in the experimental group had excellent repair than that seen in the control and blank group, both bone union and the period of bone mature were earlier than that seen in the control and blank groups. There was fibration in the blank group at 12th week. Conclusion The result indicated that PLA is a material able to be used as a carrier of BMP in inducing osteogenesis, it has a better effect of inducing osteogenesis than xenogenous cancellous bone matrix. Compared with other carriers, PLA has the following advantages 1)It releases BMP gradually during degradation, so the BMP concentration in bone defect can be maintained effectively. 2)It is a material with some rigidity, so is able to exert flexible fixation of the fractures. 3)It can be shaped to adjust itself for the individual fractures. 4)It has a good histocompatibility and an adjustable property. However, the relationship between the molecule weight, aperture of PLA and the best inducing osteogenesis need a further study.