Abstract: Abstract: Objective To observe the senescence effects and mechanisms of leukemia K562 cell line induced by ginsenoside Rg1 (Rg1). Methods The related mechanism was observed via inducing k562 cells senescence by optimal drug concentration and interaction time detected by MTT colorimetric test. Effect of Rg1 on cell cycle was analyzed using flow cytometry. The positive cells were detected by SA-β-Gal staining. The colony-formed ability were detected by Colony-Assay. The telomere lengths were detected by Southern blotting. The expression of proteins were detected by Western blotting and the ultrastructure changes were observed by transmission electron microscopy. Results Rg1 significantly inhibited the proliferation of K562 cells in vitro and arrested the cells in G2/M phase. The percentage of positive cells stained by SA-β-Gal was dramatically increased （P＜0.05）and the colony-formed ability in experimental group has been weakened（P＜0.05）. Senescence-related proteins P53、P21、P16、RB in experimental group were up-regulated（P＜0.05）. Telomere lengths became shorter. The observation of ultrastructure showed that cell volume increase, heterochromatin condensation and fragmentation, mitochondrial volume increase, lysosomes increase in size and number. Conclusions Rg1 could induce the senescence of leukemia cell line K562 and P53-P21-Rb, P16-Rb cell signaling pathway play a significant role in this process.

Key words: ginsenoside Rg1, K562 cells, senescence, mechanism