Abstract: AIM: To study the effects of nitric oxide donor sodium nitroprusside on proliferation inhibition and apoptosis in K562 human leukemia cell line.METHODS: The different concentration of sodium nitroprusside and K562 cell were cultivated at the different time in vitro.The proliferation inhibition was analyzed by MTT assay and alive cell count.Cell apoptosis was analyzed by cell morphology, DNA agarose gel electrophoresis, DNA content, and Annexin V/PI labeling method.The TDTmediated dUTP nick end labeling (TUNEL) assay was used to quantitate the cell apoptosis in situ.The PFC and the blank were used as controls.RESULTS: NO inhibited K562 cell proliferation within a certain range of treating time and dosage, and a majority of K562 cells were arrested in G₀/G₁ phase.The K562 cells apoptosis was confirmed by type cell morphology, DNA fragment, sub-G₁ phase, TUNEL and Annexin V/PI labeling method with a time and dosage relationship, and the control group had no change like this.CONCLUTION: NO can suppress proliferation of K562 cell line by arresting G₀/G₁ phase and trigger apoptosis of the line.

Key words: sodium nitroprusside, cell line, K562, proliferation, apoptosis