[Mitochondrial membrane potential at HL-60 cell apoptosis induced by cytarabine]

This study was aimed to investigate the changes of mitochondrial membrane potential (DeltaPsim) of HL-60 cells induced by cytarabine and the correlation between mitochondrial membrane potential and apoptosis of HL-60 cells. HL-60 cells were stained with Rhodamine 123; change of mitochondrial membrane potential of HL-60 cells was detected by flow cytometry. AO/EB staining and flow cytometry were used to examine the apoptosis of HL-60 cells. The results showed that the levels of HL-60 cell DeltaPsim in experimental groups decreased after cultured for 6 hours. In Ara-C 0.05 mg/ml group, rhodamine 123 fluorescence intensity in mitochondria of HL-60 cells at 6, 12, 24 hours were 117.9+/-7.6, 100.9+/-7.7, 87.6+/-10.7, respectively, there was significant difference between the different culture groups (p<0.05). In Ara-C 0.1 mg/ml group, rhodamine 123 fluorescence intensity in mitochondria of HL-60 cells at 6, 12, 24 hours were 111.9+/-10.1, 86.6+/-9.2, 68.4+/-12.2, respectively, there was significant difference between the different culture groups (p<0.05); rhodamine 123 fluorescence intensity was significantly different between the two groups at 12, 24 hours (p<0.05). In Ara-C 0.05 mg/ml group, the apoptosis rate of HL-60 cells at 6, 12, 24 hours were (41.2+/-3.0)%, (53.7+/-5.1)%, (65.8+/-2.6)% respectively, there was significant difference between the different culture groups (p<0.01); In Ara-C 0.1 mg/ml group, the apoptosis rate of HL-60 cells at 6, 12, 24 hours were (45.7+/-4.1)%, (58.2+/-4.3)%, (70.1+/-2.3)% respectively, there was significant difference between the different culture groups (p<0.01); the apoptosis rates showed no significantly difference between the two groups at same time. The changes of mitochondrial membrane potential and apoptosis rate of HL-60 cells were significantly negatively correlated. In Ara-C 0.05 mg/ml group, r was -0.89, p<0.01, while in Ara-C 0.1 mg/ml group, r was -0.76, p<0.01. It is concluded that the mitochondrial membrane potential on HL-60 cells decrease at HL-60 cells apoptosis induced by Ara-C, therefore the reduction of mitochondrial membrane potential may be one of the important mechanisms at the induced apoptosis.