摘要目的 探讨碘过量对Fischer大鼠甲状腺细胞(FRTL)线粒体过氧化损伤的早期影响.方法 分别用含0.0(对照)、0.1 mmol/L碘化钾(KI)的培养基培养FRTL细胞2、4、24 h.利用线粒体超氧化物指示剂(MitoSOX)通过流式细胞术和荧光显微镜检测线粒体超氧化物生成,免疫细胞化学法检测细胞色素C(cyt c)释放,比色法检测细胞培养液上清乳酸脱氢酶(LDH)活力,利用碘化丙啶通过流式细胞术检测死亡细胞百分比,DNA电泳检测凋亡DNA片段.结果 0.1 mmol/L KI处理2、4、24 h时,FRTL细胞线粒体超氧化物生成均较对照组升高,以2h升高最明显;cyt c强阳性细胞率分别为(35.3±3.6)％、(45.8±5.5)％、(30.3±6.1)％,明显高于对照组[(14.8±1.2)％,P均＜ 0.05];LDH活力分别为(1.85±0.32)、(6.63±0.42)、(8.35±0.34)U/mg,其中4、24 h时明显高于对照组[(0.89±0.04)U/mg,P均＜0.05];对照组和0.1 mmol/L KI处理2、4、24 h组死亡细胞百分比分别为4.66％、7.52％、9.29％、13.71％;0.1 mmol/L KI处理24 h时,出现DNA ladder.结论 碘过量处理2h可引起FRTL细胞线粒体过氧化损伤,24 h可引起细胞凋亡.

abstractsObjective 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.