Fig. 6

Senescence features and irreversible growth detention during culture of DMSC in the presence of MPA. a Photomicrograph of blue-colored staining for SA-β-gal activity in low confluency DMSC cultured with MPA for 72 h. Cells exposed to sublethal dose of H₂O₂ were used as positive control. H₂O₂ at a concentration of 250 µM was added to the culture for 4 h, then washed and cells incubated in fresh medium for additional 72 h. Untreated DMSC display a fibroblast-like morphology. MPA treated cells became larger in size and more flattened. b Growth kinetics of cultured DMSC. At day 1, cells were plated in 24-well plates in complete medium (10% fetal bovine serum) and 6 h later cells were arrested either by replacing the medium by 0.2% serum or by adding MPA. After 4 days, cells were washed, and then cultured in 10% serum-containing medium (arrow). Daily, cells were harvested and counted and the accumulated population was calculated (**P ≥ 0.01****P ≥ 0.0001)