Fig. 3

Metformin attenuated OA chondrocytes senescence in vitro. Chondrocytes were divided into Metformin treatment group (Metformin), Metformin + miR-34a group (Met + miR-34a), Negative Control group (NC) and Metformin + siRNA-SIRT1 group (Met + si-SIRT1). After treated with 1 mM metformin for 48 h, chondrocytes were transfected with 100 nM miR-34a negative control (b), miR-34a mimics (c) or siRNA-SIRT1 (d) for 48 h, respectively. NC group (a) was treated with culture medium as blank control. Percentage of SA-β-gal-positive chondrocytes were calculated. (e) metformin attenuated OA chondrocytes senescence and this effect was reversed by transfection of microRNA-34a mimics or siRNA against SIRT1. All experiments were repeated three times. *P < 0.05. **P < 0.01