The effect of microRNA-21 on proliferation and matrix synthesis of chondrocytes embedded in atelocollagen gel

The objective of this study was to investigate the effect of microRNA-21 (miR-21) on the proliferation and matrix synthesis of chondrocytes embedded in atelocollagen gel. Articular cartilage was harvested aseptically from the knee and hip joints of rats. In the experimental group, double-stranded miR-21 was transfected into the chondrocytes, and in the control group, scrambled siRNA was used. After that, chondrocytes were cultured in atelocollagen gel for 3 weeks. At 1, 2, and 3 weeks after transfection, the cell numbers were counted, and the expression levels of Col2a1 and aggrecan were measured by real-time PCR. Histological analysis by toluidine blue staining was performed at 3 weeks. The cell number in the experimental group rapidly increased compared to the control group. The expression levels of Col2a1 and aggrecan in the experimental group were higher than in the control. Histological analysis revealed that many more cells with a metachromatic stain were present in the experimental group than in the control. This study demonstrated that miR-21 promotes high proliferation and matrix synthesis of chondrocytes embedded in atelocollagen gel.