Abstract: Objective To investigate the effects of zinc on apoptosis of prostate cancer cells(PC-3M). Methods The cell proliferation was determined by MTT assay treated with different concentrations of ZnSO₄•7H₂O(end concentrations were 6.25，15，25，50，100，150，200，250，and 300 μmol•L^-1,respectively), the cell morphological changes after exposed to zinc for 24 h was observed under phase-contrast microscope, the apoptosis was detected by AO/EB assay, the cell cycle and apoptotic peak were detected by flow cytometry, DNA fragmentation was observed by agarose gel electrophoresis(AGE).Results PC-3M cells proliferation rate was obviously changedafter exposed to different levels of zinc for 24 h. Zinc(250 μmol•L^-1) inhibited proliferation of PC-3M cells (P<0.01). Compared with control cells, the changes of morphological characteristics of PC-3M cells were found,including shrank and floated,decreased refraction in the cells exposed tozinc (250 μmol•L^-1) for 24 h. The confocal microscopy showed the changes of cells through AO/EB staining.The cellular membrane was integrity but vacuolization of the cytoplasm,chromatin was flavo-green, nuclear condensed, nuclear side collection, caryolysis, nuclear fragmented. The flow cytometry showed the hypodip-loid peak in G₀/G₁ phase after exposed to zinc (250μmol•L^-1)for 24 h. It had visible DNA fragmentation by AGE.Conclusion Zinc with high concentrationcan inhibit human prostate cancer cell growth and induce apoptosis of human prostate cancer cells.

Key words: PC-3M, apoptosis 