Expansion of human umbilical cord derived mesenchymal stem cells in regenerative medicine

Figure 12  Cell senescence analysis. A: The effect of recultured human umbilical cord-mesenchymal stem cells (hUC-MSCs) on cellular senescence: The β-galactosidase senescence staining was observed under bright field microscope. The results showed that none of the cells were stained blue, at primary isolated recultured hUC-MSCs isolated (R1-R10), indicating no signal of senescence; B: The graphical representation of human telomerase reverse transcriptase (hTERT) expression in recultured hUC-MSCs: To evaluate the normalized telomerase activity quantitative real-time polymerase chain reaction was performed in triplicate at passages 1-6. The X-axis represents the MSCs derived from recultured hUC at three recultured range and Y-axis represents hTERT expression normalized to housekeeping gene hydroxymethyl-bilane synthase. The hTERT expression at recultured 1-4 and 5-7 showed no significant difference. However, a significant increase in hTERT activity at recultured 8-10 was observed. Values are presented as mean ± SD from three independent experiments. NS: No significance, ^bP < 0.01. hUC: Human umbilical cord; MSC: Mesenchymal stem cell.