Figure 3. Actin stress fibers formation induced by IL-1β in OA chondrocytes and effect of CM. Presence of actin stress fibers (green pixels) in a representative experiment of N=4 separate experiments with cells from separate donors. DAPI was used to stain the nuclei. Bars: 50 μm. OA chondrocytes were incubated with IL-1β and/or CM for 1 day and 3 days.