Figure 5

Cellular senescence of bone marrow stromal cells (BMSCs).

(a–g) Representative beta-galactosidase (β-gal) staining images demonstrating cellular senescence of murine BMSCs derived from the control groups (a) and osteoporoses induced by natural aging (b), accelerated senescence (SAMP6) (c), ovariectomy (OVX) (d), type 1 diabetes (T1D) (e), excessive glucocorticoids (GIOP) (f) and orchidectomy (ORX) (g). Mice were sacrificed after 4 weeks of modeling. 1^st-passaged BMSCs were seeded at 1 × 10⁵ cells/well in 12-well plates and were stained for β-gal. The senescent cells were positively stained (green). Bars: 200 μm. (h) The corresponding percentage of senescence-associated β-gal positive cells over total cells showing increased senescence of BMSCs in osteoporoses except in T1D. BMSCs from natural aging mice developed the highest senescent percentage. (i,j) Quantitative real-time polymerase chain reaction (qRT-PCR) analysis of the mRNA expression level of p53 (i) and p16 (j). The corresponding values showing increased senescence of BMSCs in osteoporoses except in T1D. BMSCs from natural aging mice expressed the highest levels of p53 and p16. The expressions of p53 and p16 were normalized to that of ACTIN. Data represents mean ± standard deviation (SD). n = 6 per group. ^aP < 0.05 with the control groups; ^bP < 0.05 with the natural aging group; ^cP < 0.05 with the SAMP6 group; ^dP < 0.05 with the OVX group; ^eP < 0.05 with the T1D group; ^fP < 0.05 with the GIOP group; ^gP < 0.05 with the ORX group.