Figure 4

miR-9 is also involved in the degeneration of articular chondrocytes. (A) Rabbit articular chondrocytes were treated with 5 nM IL-1β in the absence or presence of 100 nM of the miR-9 inhibitor. Change in expression level of miR-9 in was analyzed by real-time PCR. (B) Images of the cultures were captured using light microscopy (Upper panel). Changes in the protein level of Type II collagen and PRTG during chondrogenesis were analyzed by Western blotting (Lower panel). GAPDH was used as control. (C) Rabbit articular chondrocytes were treated with 5 nM IL-1β in the absence or presence of miR-9 precursor. Images of the cultures were captured using light microscopy (Upper panel). Changes in the protein level of Type II collagen and PRTG during chondrogenesis were analyzed by Western blotting (Lower panel). GAPDH was used as control. (D) Rabbit and human articular chondrocytes were treated with 5 nM IL-1β in the presence of 100 nM of the miR-9 inhibitor or the PRTG construct. The number of viable cells was determined at 2 day of culture. (E) Human articular chondrocytes were electroporated with PRTG, miR-9 inhibitor, or miR-9 in the absence or presence of IL-1β (left panel) and apoptotic cell death (right panel) was analyzed. (F) Human articular chondrocytes isolated from biopsy normal cartilage were electroporated with Prtg or miR-9 inhibitor in the presence of TGF-β3 and apoptotic cell death was analyzed. Change in expression level of miR-9 in was analyzed by real-time PCR. *, statistically different from control cells (p < 0.001). The error bars represent average of data from each human sample. Scale bar, 200 μm.