Fig. 4

Hypoxic preconditioning alleviates the cellular senescence of OM-MSCs in vitro model. A Viability of OM-MSCs treated with Hemin for different lengths of time. B, C Western blotting for p21, P53, and p16INK4A in normoxia and hypoxia OM-MSCs treated with hemin for 18 h. D Representative images of SA-β-gal activity staining. E Number of SA-β-gal-positive cells. Data are expressed as the mean ± SEM (n = 3) (^*P <0.05, ^**P <0.01, ^***P <0.001, ns. no significance)