Figure 5. Suppression of MEK/ERK pathway in senescent cells leads to accumulation of damaged mitochondria and reactive oxygen species (ROS). (A) Damaged mitochondria accumulate in senescent cells with suppressed MEK/ERK (according to Mitotracker Green and Mitotracker Red in vivo staining). At indicated time points cells were stained with Mitotracker Red and Mitotracker Green and images were acquired using Leica TSC SP5 microscope. (B) Graphical representation of Mitotracker Red/Mitotracker Green intensity ratio in control and treated cells. ImageJ software was used to analyze the images. (C) ROS accumulate in senescent cells with suppressed MEK/ERK after 72 h of cultivation. At indicated time points cells were incubated with DCF-DA and fluorescence was measured at proper wavelength. Data are presented as mean ±S.E.M. of three independent replicates (n=3).