Telomere length in human bone marrow stem cells (hBM-MSCs) at different culture passages. (A) Telomere length evaluated by Southern blotting in hBM-MSCs (donors 1, 2, 5, 7, and 8) at P0, P3, P6, P9, and P12. The size marker is indicated on the left, and the positive control DNA used is a purified genomic DNA from immortal cell lines. Differences in telomere length were observed between P0, P3, and the following passages (P6, P9, P12) examined. (B) ANOVA statistical analysis of telomere length (donors 1, 2, 5, 7, and 8). A medium spot in the range of telomere length (smear, A) was calculated (see Material and Methods), and a mean value between donors (x axis) was calculated for each passage. Data are expressed as mean ± SEM. No significant differences in the mean values of telomere lengths were observed between P0 and P3, whereas significant differences were observed between P3 and P6 (P < 0.05), and between P0/P3/P6 and P9/P12 (P < 0.001).