Objective      To investigate the effect of miR-29b on regulating cell hypertrophy in the differentiation of bone marrow mesenchymal stem cells (BMSCs) into chondrocytes.       Methods      BMSCs were cultured and induced into hypertrophic chondrocytes. Collagen type Ⅱ (Col Ⅱ

marker of chondrocytes) and collagen type X (Col X

marker of hypertrophic chondrocytes) were detected by qRT-PCR. Safranin O staining was employed to confirm the hypertrophic state of the chondrocytes

and then the expression of miR-29b in the transcriptional level was detected by qRT-PCR. In the experiment

the BMSCs were divided into the following groups: miR-29b over-expression group

miR-29b inhibition group

over-expression negative control group and inhibition negative control group. The expression of the related markers in the 4 groups were detected.       Results      In the miR-29b mimics group

the expression of Col Ⅱ was decreased significantly compared with the control group (P0.05)

while the expression of Col X and Runx2 was significantly increased (P0.05). However

the expression of Col Ⅱ in the miR-29b inhibition group was significantly higher than that in the control group (P0.05)

while that of Col X and Runx2 was significantly reduced (P0.05).       Conclusion      MiR-29 can effectively promote hypertrophy of BMSC-derived chondrocytes

and the inhibition of miR-29 can stabilize the phenotype of BMSC-derived chondrocytes.