Cellular apoptosis was determined sing acridine or ange staining of magnesium oxide nanoparticle-treated and untreated embyos at 96 hpf.(A)Whole-embryo cell death images were detected by fluorescence microscope.a-1,controlgroup;a-2,50mg/ltreatedgroup;a 3 , 100mg/ ltreated group; a-4,200mg/ltreated group and a-5,400mg/ltreatedgroup.(B)Therelative fluorescence of cell death was detected. Data are expressed as mean 7S.D. from four independent experiments(*po0.05).