Activation of Smad signalling in OA chondrocytes after growth factor stimulation.

<p>Chondrocytes were cultured in monolayer and stimulated with each of the four GDF5 proteins for 15 minutes, 30 minutes, 1-β1 stimulation for 1 hour was used as a positive control. Protein was extracted and subjected to western blot analysis using an antibody against Smad 1/5/8 (anti-Smad1/5/8), with anti-β-actin antibody used as a loading control. This data comes from one OA patient. Identical data was obtained for a second OA patient (data not shown).