The Study On Rat Alveolar Macrophages(NR8383) Apoptosis Caused By Rare Earth Neodymium Oxide Particles

Objective This research was aimed to investigate the toxicity and neodymium oxide particles in the pulmonary macrophage NR8383 cells and the mechanism of apoptosis.Method NR8383 cells were exposured to neodymium oxide suspension with final concentrations of 0,3.125,6.25,12.5,25,50?g/ml for 6,12,24 h.MTT method was used to assay the cell inhibition rate.Cells were collected for apoptosis and ultrastructure detecting when they were exposure to neodymium oxide for 24 h.Fluorescence quantitative PCR and western blot was employed to determine the expression of Fas,FasL and Caspase-8.Results Compared with the control group,the inhibition rate of NR8383 were increased after exposure to neodymium oxide at different concentrations and time.The difference was statistically significant(P<0.05).The percentages of early apoptotic stage cells of groups 6.25,12.5,25?g/ml were higher than that in control group,the difference was statistically significant(P<0.05).In 0~25?g/ml concentration range,with the concentration increasing,percentages of the late apoptotic stage cells(1.8%,2.4%,2.6%,3.8%,4.1%)raised.The percentage of early apoptotic stage cells of groups 12.5,25 and 50?g/ml were higher,compared with control group,the difference was statistically significant(P<0.05).However,the percentage of apoptotic cells began to decline when cells exposed to 50?g/ml.trans-electric microscope research showed that the control group shows a complete cell morphology,cells exposed to 3.125?g/ml and6.25?g/ml neodymium oxide are shrink and chromatin aggregation,while the membranes kept integrity.With the exposure concentration increased,membranes were cracked,nuclear were fragmented,and a small amount of chromatin was divided into blocks,apoptotic bodies could be observed in 50?g/ml groups.Compared with the control group,the Fas/FasL and Caspase-8 m RNA and protein expression in the cells of the 6.25?12.5and 25?g/ml groups were up-regulated(P<0.05).Conclusions apoptosis could be induced in rat alveolar macrophages with neodymium oxide exposure,Fas/FasL signaling pathway was turned on and should be one reason of apoptosis initiated.