BMP2 promotes chondrocyte proliferation via the Wnt/β-catenin signaling pathway.

Bone morphogenetic protein 2 (BMP2), a member of the transforming growth factor-β (TGF-β) superfamily, plays a key role in the induction of the differentiation of mesenchymal cells into chondrocytes to form cartilage tissue. However, it is not clear whether BMP2 regulates the proliferation of chondrocytes. In the present study, the effect of BMP2 on the proliferation of chondrocytes and its underlying mechanism was investigated. Chondrocytes isolated from the knee of SD rats were cultured and identified using toluidine blue staining. The second generation chondrocytes were collected and stimulated with or without BMP2 for 48 h. Cell viability was analyzed using the MTT assay. mRNA and protein expression levels of β-catenin, GSK-3β, Dvl1 and Cyclin D1 were detected using real-time RT-PCR and Western blotting, respectively. The cell cycle distribution of the chondrocytes was analyzed by flow cytometry. BMP2 stimulation was found to significantly increase cell viability. In addition, following BMP2 treatment, β-catenin, Cyclin D1 and Dvl1 expression was significantly increased, whereas GSK-3β expression was significantly decreased. Moreover, the percentage proportion of chondrocytes in the G0/G1 phase was significantly decreased, whereas that in the S phase was significantly increased. The results indicate that BMP2 promotes chondrocyte proliferation via the Wnt/β-catenin signaling pathway.