Bone repair investigation using rhBMP-2 and angiogenic protein extracted from latex.

Background: The aim of this work was to study the new bone tissue formation after bone morphogenetic protein type 2 (rhBMP-2) and P-1 application, using 5 and 10 μg of each, combined to a material carrier, in critical bone defects.

Methods: It was used 70 Wistar rats (male, ∼250 g) that were divided in 10 groups with seven animals on each. Groups are the following: critical bone defect only, pure monoolein gel, 5 μg of pure P-1, 5 μg of pure rhBMP-2, 5 μg of P-1/monoolein gel, 5 μg of rhBMP-2/monoolein gel, 10 μg of pure P-1, 10 μg of pure rhBMP-2, 10 μg of P-1/monoolein gel, 10 μg of rhBMP-2/monoolein gel. Animals were sacrificed after 4 weeks of the surgical procedure and the bone samples were submitted to histological, histomorphometrical, and immunohistochemical evaluations.

Results: Animals treated with pure P-1 protein, in both situations with 5 μg and 10 μg, had no significant difference (P > 0.05) for new bone formation; other groups treated with 10 μg were statistically significant (P < 0.05) among themselves and when compared with groups in which it was inserted the monoolein gel or critical bone defect only (P < 0.05). In the group involving the 10 μg rhBMP-2/monoolein gel association, it was observed an extensive bone formation, even when compared with the same treatment without the gel carrier.

Conclusion: Using this experimental animal model, more new bone tissue was found when it was inserted the rhBMP-2, especially when this protein was combined to the vehicle, and this process seems to be dose dependent.