Peroxide effects of iodide excess on mitochondria in Fischer rat thyroid cell line in the early period / 中华地方病学杂志

ABSTRACT

Objective To investigate the peroxide effects of iodide excess on mitochondria in Fischer rat thyroid cell line(FRTL) in the early period.Methods After treatment with 0.0 mmol/L(control group) or 0.1 mmol/L potassium iodide(KI) for 2,4 and 24 h,respectively,changes of mitochondrial superoxide formation were assayed by flow cytometry and fluorescence microscopy using mitochondria-targeted hydroethidine(MitoSOX).The cytochrome c (cyt c) released from mitochondria to cytoplasm was detected by immunocytochemistry.The lactate dehydrogenase (LDH) released into supernatant was measured by a LDH kit using colorimetry.The percent of dead cells was assayed by flow cytometry using propidium iodide (PI).DNA with loading buffer was separated in 1％ agarose gel.Results Mitochondrial superoxide production in FRTL cells treated with 0.1 mmol/L KI was increased at 2; 4 and 24 h,especially at 2 h.The rates of cyc c protein immunity positive cells at 2,4 and 24 h in 0.1 mmol/L KI group were (35.3 ± 3.6)％,(45.8 ± 5.5)％ and (30.3 ± 6.1)％,respectively,which were significantly higher than that in control group[(14.8 ± 1.2)％,all P ＜ 0.05].The LDHs released into supernatant at 2,4 and 24 h in 0.1 mmol/L KI group were (1.85 ± 0.32),(6.63 ± 0.42) and (8.35 ± 0.34)U/mg,and these values at 4 and 24 h in 0.1 mmol/L KI group were significantly higher than that of control group[(0.89 ± 0.04)U/mg,all P ＜ 0.05].After incubation with 0.1 mmol/L KI for 2,4 and 24 h,the percentages of dead FRTL cells were 7.52％,9.29％ and 13.71％,respectively,while that of control group was 4.66％.After FRTL cells were treated with 0.1 mmol/L KI for 24 h,DNA ladder appeared.Conclusion Iodide excess (0.1 mmol/L) can cause mitochondrial peroxide injury in FRTL cells at 2 h and cell apoptosis at 24 h.