Effects of the combination of fibroblast growth factor-2 and bone morphogenetic protein-2 on the proliferation and differentiation of osteoprecursor cells.

OBJECTIVES

Fibroblast growth factor (FGF) plays a critical role in bone growth; FGF-2 is known to be an important regulator of osteoblast activity because it stimulates osteoblast replication and decreases differentiation markers. Bone morphogenetic protein-2 (BMP-2) has been shown to be an active inducer of osteoblast differentiation and stimulates expression of mineralization-associated genes.

MATERIAL AND METHODS

The dose-dependent impact of FGF-2 and BMP-2 on the cellular proliferation and differentiation of osteoprecursor cells was evaluated. The alkaline phosphatase activity (ALP) test was performed to assess differentiation, and protein expressions related to bone formation were measured using the Western blot analysis.

RESULTS

Cultures grown in the presence of FGF at 20 ng/mL showed significantly increased value when compared with control group and cultures loaded with FGF-2 at 20 ng/mL, and BMP-2 at 100 ng/mL showed significant decrease in cellular proliferation when compared with cultures loaded with FGF-2 at 20 ng/mL. The ALP activity increased when cells were treated with 10 and 100 ng/mL BMP-2, with relative ALP activity of 213.1% and 312.5%, respectively, when ALP activity of the uncontrolled control was considered 100%. However, when 100 ng/mL BMP-2 was combined with 20 ng/mL FGF-2, the relative increase reached up to 392.2%, but this did not reach a statistically significant increase when compared with 100 ng/mL BMP-2 alone.

CONCLUSIONS

Within the limits of this study, BMP-2 significantly enhanced osteoblast differentiation but combined delivery of FGF-2 and BMP-2 did not produce synergistic effects on osteoblast differentiation under the current experimental condition.