F-actin staining

NHDF cells were evenly seeded in 6-well plates and subsequently grown to 70–80% confluence. The cells were then treated with MED (100, 200 or 400 μg/mL) for 24 h. After discarding the supernatants, cells were fixed for 20 min with 4% formaldehyde at room temperature. After fixation, the cells were washed with 1× PBS and permeabilized using 0.1% Triton-X in PBS. Then, cells were stained with F-actin staining Actin Red 555 Ready Probes (Thermo Fisher Scientific Inc.) in PBS and imaged using a fluorescent microscope (Evos m5000, Thermo Fisher Scientific Inc.) at 200× and 400× magnification.