Characterization of the <i>in vitro</i> model of aging.

<p>Young, intermediate and aged fibroblasts are represented by passage 3 (white), 5 (gray) and 8 (black bars), respectively. Data shown are representative of three independent experiments. (A) Acid β-galactosidase detection during <i>in vitro</i> aging. Acid β-galactosidase positive senescent cells appear in blue. The histogram reports the senescent/total cells ratio in the three conditions. This ratio was set to 100% for p3. (B) Fibroblasts proliferation is decreased during <i>in vitro</i> aging. Cells were incubated with the Uptiblue reagent and proliferation was evaluated by measuring the absorbance at 560nm. The results are expressed as a percentage of p3 condition value. (C) Evaluation of ROS production during <i>in vitro</i> aging. ROS production was detected by fluorescence using the Image-iT LIVE Green Reactive Oxygen Species Detection Kit. (λ _excitation 495nm / λ _emission 529nm). The results are expressed as a percentage of p3 condition value. (D) Evalution of MMP-1 secretion during <i>in vitro</i> aging. MMP-1 secretion was determined by ELISA. The results are expressed as a percentage of p3 condition value. *, <i>p<</i>0.05, ***, <i>p</i><0.01.