地塞米松影响小鼠胸腺细胞线粒体膜电势变化研究

目的：研究地塞米松刺激小鼠胸腺细胞过程中线粒体膜电势（△Ψm）的变化。 方法： 以终浓度1×10－6mol/L地塞米松（DEX）刺激小鼠胸腺细胞，通过JC-1染色流式细胞术，在0、1、3、5、7、9、11、24和27 h时点分别检测小鼠胸腺细胞平均J-aggregate（FL2）和平均J-monomer （FL1）含量，并计算线粒体膜电势（FL2/FL1）。 结果： 本研究中，小鼠胸腺细胞离体后FL1所反映的线粒体质量迅速下降，至5 h对照组达到平台期（913.38±70.11），然后缓慢下降到27 h的（622.80±22.81）。DEX组FL1在1 h和3 h与对照组没有显著差异（P>0.05），而从5 h（660.91±72.95）开始显著低于对照组（P<0.01），并且随培养时间延长呈下降趋势，至27 h的（309.70±53.35）。对照组和DEX组FL2随培养时间延长而降低。1-9 h，对照组和DEX的△Ψm没有显著差异（P>0.05）。而在11、24和27 h，对照组△Ψm分别为（256.41±21.59）、（214.14±23.21）和（146.14±17.97），而DEX组△Ψm显著低于对照组（P<0.01），分别为（138.28±20.59）、（111.61±29.67）和（72.92±17.86）。 结论： DEX诱导小鼠胸腺细胞凋亡过程中，线粒体质量降低和△Ψm下降是早期事件，而细胞内现存线粒体△Ψm下降则是较晚期的事件。在本研究中，线粒体质量下降与现存线粒体膜电势的变化之间关系不紧密。

Changes of mitochondrial membrane potential in mouse thymocytes stimulated by dexamethasone

AIM: To study the changes of mitochondrial membrane potential (△Ψm) in mouse thymocytes stimulated by dexamethasone (DEX). METHODS: Mouse thymocytes was stimulated by 1×10-6 mol/L DEX. J-aggregate (FL2) and J-mononer (FL1) was measured by JC-1 staining flow cytometry at 0 h, 1 h, 3 h, 5 h, 7 h, 9 h, 11 h, 24 h and 27 h. △Ψm was calculated by (FL2/FL1). RESULTS: The mitochondrial mass of mouse thymocytes decreased rapidly in control group in vitro. FL1 got platform at 5 h (913.38±70.11), then decreased till 27 h (622.80±22.81). In DEX group, there was no significant difference (P>0.05) compared with control group at 1 h and 3 h; while FL1 in DEX group at 5 h (660.91±72.95) was significant lower (P<0.01) than that in control group, and decreased following culture time lapse till 27 h (309.70±53.35). The decrease in FL2 was more obvious in both control and DEX group as the elongation of culture time. There was no significant difference for △Ψm between control and DEX group from 1 to 9 h. At 11 h, 24 h and 27 h, △Ψm in control groups were (256.41±21.59), (214.14±23.21) and (146.14±17.97), respectively, while △Ψm in DEX groups at the same time points were significantly lower than controls (P<0.01), they were (138.28±20.59), (111.61±29.67) and (72.92±17.86), respectively. CONCLUSIONS: During DEX-induced mouse thymocyte apoptosis process, mitochondrial mass decreases and mitochondria depolarization are early events, and the decrease in remaining mitochondrion △Ψm is a later event. According to these results, we assume that there is no necessary relationship between the mitochondrial mass decrease and △Ψm change of remaining mitochondrion.