OBJECTIVETo demonstrate the effect of bromoxynil on membrane potential and respiratory control rate (RCR) in isolate mitochondria from mice liver tissue in vitro and the intervention of NAC.

METHODSThe mitochondrial was randomized to control group, bromoxynil-poisoned group and NAC-protected group. S3, S4 and RCR of the mitochondria in each sample was detected by the method of oxygen electrode. Each sample was stained by JC-1 and the changes of membrane potential of mitochondria were observed under fluorescence microscope.

RESULTSThe S3 [(0.031 +/- 0.008) nano atoms oxygen x mg(-1) x min(-1)], RCR (1.820 +/- 0.181) of bromoxynil-poisoned group and RCR (4.253 +/- 0.210) of NAC-protected group were significantly lower than those of control group (P<0.01); the S4 [(0.017 +/- 0.004) nano atoms oxygen x mg(-1) x min(-1)] of NAC-protected group was significantly higher than control group (P<0.01). The S3 [(0.046 +/- 0.005) nano atoms oxygen x mg(-1) x min(-1)] and RCR of NAC-protected group were significantly higher than group B (P<0.01), S4 [(0.011 +/- 0.001) nano atoms oxygen x mg(-1) x min(-1)] of NAC-protected group was significantly lower than bromoxynil-poisoned group (P< 0.01). Observation under fluorescence microscope: the red fluorescence of mitochondria was dim or disappeared in bromoxynil-poisoned group while brightened in NAC-protected group but still dimmer than control group.

CONCLUSIONIn vitro, the mitochondrial RCR and the mitochondrial membrane potential are decreased after the mitochondria is incubated with bromoxynil, and NAC could improve it.