Effect of bone morphogenetic protein-2 on proliferation and osteogenic differentiation of human umbilical cord mesenchymal stem cells in vitro

Abstract

Objective To study the effects of the bone morphogenetic protein-2 (BMP-2) on proliferation and osteogenic differentiation of human umbilical cord mesenchymal stem cells (hUCMSCs) in vitro. Methods hUCMSCs were cultured in vitro, and BMP-2 (20 mg/L) was added into the culture medium. The proliferation effect of BMP-2 on hUCMSCs was examined by MTT assay. The proportion of antigen-positive cells for STRO-1 was observed by flow cytometry (FCM). The osteopontin ( OPN), alkaline phosphatase (ALP) and type 1 collagen ( COL1 ) mRNA levels was detected by reverse transcription-polymerase chain reaction ( RT-PCR). The ALP activity was tested by ALP staining array. Von Kossa staining method was used to study the calcification effects. Results The proliferation rate was increased 1-, 3-,5-, 7-day BMP-2 (20 mg/L) groups and no BMP-2 group, but there was no statistically significant difference among groups (P ＞ 0. 05). When the concentration of serum in the culture medium decreased from 10% to 2%, the proliferation was just increasing 10% and no different between BMP-2 group and no BMP-2 group (P＞0.05). The percentages of STRO-1 positive cells was increasing from 25.1 ±4.0 to 51.1 ±6.4 after culture with BMP-2( P ＜ 0.01 ). The BMP-2 increased the ALP and COL1 gene expression, induced the OPN gene expression. A lot of hUCMSCs was positive in ALP staining array in BMP-2 medium. Many mineralized nodes was detected in the Von kossa staining method after culture 28 days in the BMP-2 medium.Conclusion BMP-2 can promote the osteogenic differentiation,and have a little effect on the prolferation of hUCMSCs. Key words: Bone morphogenetic protein-2; Umbilical cord mesenchymal stem cell; Osteogenic differntiation