Figure 9.

hWJ-MSC SA β-Gal activity after H₂O₂ treatment. Effect of H₂O₂ treatment expressed in term of ratio between the percentage of blue cells in treated sample and the relative percentage of blue cells in untreated sample after 1 h (Panel A) and 2 h (Panel B) of treatment. In each panel the effect of every H₂O₂ concentration was presented after 24, 48 and 72 h from the end of the stimulus. Data were obtained in triplicate from one subject and expressed as ratio (n=3) ± SD. Control value is 1 (not shown) and treatment was arbitrarily considered effective when ratio was >3. In Panels (C) and (D) the effects of different H₂O₂ concentrations on hWJ-MSC SA β-Gal activity tested at 48 h from the end of the treatment are shown. In Panel (C), a graph representative of three (obtained from three different subjects) showing the percentage of blue cells in untreated (CTR) and treated cells after 1 and 2 h of H₂O₂ treatment. Data were expressed as percentage of blue cells ± SD. Panel (D): representative SA β-Gal staining images of hWJ-MSCs untreated (CTR) and treated with H₂O₂ at final concentrations of 100 μM, 150 μM and 200 μM after 2-h treatment. Cells were analyzed under a light microscope (at 200× magnification) and cell images were detected under bright field illumination with the Leica MC170 HD Imaging System. Blue staining indicates senescent cells and scale bars correspond to 100 μm.