Abstract: AIM: To investigate the changes of reactive oxygen species (ROS) and Ca^{2 +}levels in K562 cellsinduced by simvastatin to predict the mechanism of apoptosis.METHODS: K562 cells cultivated in routinemethod were treated with 20 μmol·L^-1simvastatin.Themorphology change was observed under light microscope after 24 h.Flow cytometry assay was used to detect the apoptotic ratio, the ROS and the Ca2⁺levels.RESULTS: 24 h after K562 cells had been treated with 20μmol·L^-1simvastatin, there were some morphological changes of the cells such as karyopyknosis, nuclear fragmentation and apoptotic body emerged.AnnexinV-FITC/PI was used to detect the apoptic ratio of K562 cells, the apoptotic ratio of treated groups was markedly increased compared with the control groups in a time-dependent manner.ROS, which was detected by 2', 7' -dichloro fluorescein diacetate (DCFH-DA), was markedly increased in treated groups compared with the control groups at different time points (12, 24, 48, 72 h), and the level ROS got its peak time after 24 h.The Ca^{2 +}, which was detected by Fluo-3AM, was markedly increased in treated groups compared with the control groups at different time points, and the level ROS got its peak time after 12 h.CONCLUSION: K562 cells can be induced toapoptosis by simvastatin.The potential mechanism of apoptosis might be related to the increase of ROS and Ca²⁺level.

Key words: simvastatin, apoptosis, calcium, reactive oxygen species