Figure 1.

Lactose induced senescence signs in normal fibroblast cells. A. Senescence-associated β-galactosidase (SA-β-gal) staining in normal, middle-age diploid human cells (MRC-5 cell lines, Passage 23-25) treated with vehicle, lactose, and doxorubicin for 7 days (10×). Scale bar =100 μm. B. The cells incubated with lactose (7 days) and cellular senescence examined by SA-β-gal staining. C. The cells incubated (from 0-7 days) with 25 mM lactose and cellular senescence examined by SA-β-gal staining. D. MRC-5 cells treated with lactose and doxorubicin for 7 days. Whole cell lysates analyzed by western blotting with antibodies p16^ink4a. β-actin was used as a loading control. Results (mean ± SD) obtained from three independent experiments. E. Concentration of lactose in cells (104 cell equivalent per ELISA well) with varying concentrations of lactose added to the cells for 7 days. F. Concentration of lactose in cells (104 cell equivalent per ELISA well) incubated with 25 mM lactose. G. Cell viability determined by CCK-8 assay kit. MRC-5 cells were treated with the indicated concentration of lactose for 24 hours. *P<0.05, **P<0.01, ***P<0.001 (ANOVA): *Lactose versus vehicle.