Research Paper Volume 12, Issue 8 pp 6823—6851

Figure 4. IGFBP2 expression progressively increases during senescence changes in psoriatic KC. (A) Healthy and pso KC were serially subcultured until they undergo senescence, and analysed by immunocytochemistry for the expression of IGFBP2 at two distinct culture passages (P1 and P4) (upper panels). Healthy KC were not counterstained with haematoxylin in order to preserve faint IGFBP2-specific staining (upper panels). The activity of senescence-associated β-galactosidase (SA- β-gal) was detected by colorimetric staining (blue) in healthy and pso KC cultures at passage P1 and P4. Data are representative of three independent experiments performed on different healthy (n = 3) and psoriatic (n = 3) donors. Bars, 50 μm. The graph shows the means of the percentage of IGFBP2 positive cells or SA- β-gal positive cells ± SD, counted in two adjacent fields. (B, C) WB analysis was performed on total protein lysates from healthy and pso KC at different serial passages of culture, left untreated (B) or M4-treated (C), to detect IGFBP2, p16, p21 and p-p21 expression. β-actin was used as loading control. Graphs represent the means of the densitometric intensity (D.I.) ± SD of the bands obtained from three different WB experiments. *p ≤ 0.05, **p ≤ 0.01, as calculated by unpaired Student’s t test, comparing healthy and pso KC groups, or M4-treated and untreated groups.