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Objective To investigate the effect of radiation on the mitochondrion in adenocarcinoma A549 cells.Methods After A549 cells were irradiated with 0,0.5,3 or 8 Gy of 60Co γrays,mitochondrion membrane potential of A549 cells was detected by JC-1 probe,and ATP activity was measured by ATP kit in a chemiluminescence apparatus.The mitochondria DNA copy numbers was detected by real-time PCR assay.Results At 24 h after radiation,the mitochondrion membrane potential of A549 cells in all the irradiated groups changed significantly (F =243.44,P ＜ 0.05),among which 0.5 or 3 Gy of radiation resulted in a significant increase of mitochondrion membrane potential of A549 cells (t =-10.12,-5.59,P ＜ 0.05).However,the mitochondrion membrane potential of A549 cells exposed to 8 Gy of radiation decreased significantly 24 h after radiation (t =15.22,P ＜ 0.05).The mitochondrion membrane potential of A549 cells in all radiation groups returned to the normal level 48 h after radiation (F =10.36,P ＜ 0.05).24 h after radiation,the level of ATP in A549 cells significantly changed respectively(F =97.08,P ＜ 0.05),similar to the mitochondrion membrane potential.The ATP level in 0.5 and 3 Gy groups increased significantly (t =1.66,7.27,P ＜ 0.05),and the level of ATP in 8 Gy group decreased significantly (t =-8.24,P ＜ 0.05).Furthermore,48 h after both 0.5 and 3 Gy of radiation,the ATP content in A549 cells was still higher than that in untreated A549 cells (t =4.60,8.53,P ＜0.05).The mitochondria DNA copy numbers in A549 cells increased significantly in all the radiation groups (F =118.00,P ＜ 0.05).Compared with untreated A549 cells the mitochondria DNA copy numbers in A549 cells increased at 0.5 Gy by 12 times(t =0.02,P ＜0.05),and increased at 3 and 8 Gy by 7 and 10 times,respectively (t =9.68,15.10,P ＜ 0.05).Conclusions High dose of radiation resulted in the decrease of mitochondrion membrane potential of A549 cells,which subsequently affected the production of ATP.However,radiation with moderate and lower dose could lead to the compensatory increase of mitochondrion membrane potential of A549 cells,which promoted the production of ATP.The mitochondria DNA copy numbers compensatory would increase after A549 cells were exposed to radiation within 8 Gy.
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Objective To explore the influence of mitochondrial permeability transition pore opening and cytochrome C (Cyt C) being discharged on the apoptotic mechanism of HL-60 cell induced by desferrioxamine (DFO),so as to provide scientific basis for the clinicians to adopt the strategy of iron deprivation to treat human leukemia.Methods HL-60 cells were co-cultivated with various concentration of DFO for 24-72 hours,then the apoptotic cells and the changes of mitochondrial membrane potential(△Ψm) were examined by means of flow cytometry(FCM),and Cyt C in cytoplasm was detected by way of celluar immunohistochemistry.Results The cell apoptotic rate assumed rising tendency as the highest rate could be up to (44.10 ± 6.3 1) ％,and the effect was of time-and-dose dependence (P ＜0.01).FCM could detect the △Ψm declining(P ＜ 0.05),and the Cyt C positive cell rate was higher than the controls,the differences were of statistical significance(P ＜ 0.05).Conclusions DFO can induce the HL-60 cells apoptosis,and the possible mechanism is that DFO make the mitochondrial permeability transition pore open and get Cyt C discharged from the mitochondria.
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OBJECTIVE:To observe the changes of mitochondrial membrane potential(MMP)at different time in the process of simvastatin-induced apoptosis of K562 cells.METHODS:K562 cells cultivated by routine method for 24h were treated in the 20? mol? L-1 simvastatin for 12,24,48,and 72h,respectively.And theh cell morphological changes were observed.Vitality of K562 cells was detected with MTT;flow cytometry were performed to detect cell apoptotic ratio and changes of mitochondrial membrane potential,and the detection results were compared with those in solvent control group.RESULTS:As compared with control group,the morphology changes of K562 cells such as karyopyconosis,nuclear fragmentation and apoptotic body emerged after treatment with 20? mol? L-1 simvastatin for 48h;the apoptotic ratio at 12,24,48,and 72h increased by(2.55? 0.35)%,(6.1? 0.35)%,(14.15? 0.42)%,and(30.70? 0.65)%,respectively;and the apoptotic ratio of K562 cells increased time-dependently.The cell membrane potential was decreased by(0.7? 0.24)%,(39.6? 4.80)%,(24.4? 2.45)%,and(6.0? 1.62)%,respectively,with that at 24h showing the highest decreasing rate.CONCLUSION:The change of MMP is the early events of apoptosis.The potential mechanism of K562 cells apoptosis induced by simvastatin might be related to the collapse of MMP.
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Objective To observe the change of mitochondrion membrane potential(??m) in apoptosis induced by an iron chelator(deferoxamine,DFO),and to explore the mechanism of this apoptosis in human leukemia-60(HL-60) cells.Methods HL-60 cells were co-cultivated with various concentration of DFO and FeCl_3 for certain time,resultingin status of intracellular iron deprivation and rich iron.Cell vital force was determinded by the MTT method.The cells were examined by phase contrast microscopy,flow cytometry(FCM) for evidence of apoptosis,and also by FCM for ??m.The transcription of the apoptogene of bax was detected by hybridization in situ.Results The cell growth rate assumed descent tendency.DFO could induce the apoptosis and descent ??m of HL-60 cells(P