氟康唑对热带念珠菌活性氧和线粒体膜电位的影响

为了探讨氟康唑作用机制,观察它对热带念珠菌作用后存活率、活性氧(Reactive oxygen species,ROS)、线粒体膜电位(Mitochondrial membrane potential,△Ψm)和细胞周期的变化。参照NCCLS M27-A方案的微量稀释法测定氟康唑对热带念珠菌的最低抑菌浓度(MIC);热带念珠菌与不同浓度氟康唑共同培养后用流式细胞术(Flow cytometry,FCM)分析热带念珠菌存活率、ROS、线粒体膜电位△Ψm和细胞周期的变化。结果表明,氟康唑作用后,热带念珠菌氟康唑耐药株的存活率、ROS、线粒体膜电位△Ψm和细胞周期各期比例均没有明显变化;而热带念珠菌氟康唑敏感株的存活率和线粒体膜电位△Ψm明显下降,ROS明显升高,而且大部分热带念珠菌阻滞于G2/M期,并出现明显凋亡峰,呈一定的时间剂量依赖关系。自由基清除剂谷胱甘肽抑制热带念珠菌ROS的产生,阻止细胞周期G2/M期阻滞和降低凋亡。由此可见,氟康唑可能通过刺激热带念珠菌产生过多ROS,并使线粒体膜电位△Ψm下降,从而诱导热带念珠菌凋亡。

Effect of fluconazole on reactive oxygen species and mitochondrial membrane potential of Candida tropicalis

To explore fluconazole’s effect mechanism,we investigated the changes of viability rate,reactive oxygen species(ROS),mitochondrial membrane potential(△Ψm) and cell cycle of Candida tropicalis after treatment with fluconazole.The minimum inhibitory concentration(MIC) of the clinical isolates Candida tropicalis to fluconazole were tested by NCCLS M27-A microdilution method.After treatment wth different concentration of fluconazole,viability rate,the intracellular accumulation of ROS,the loss of mitochondrial membrane potential △Ψm and cell cycle of Candida tropicalis were detected with flow cytometry,respectively.After treatment with fluconazole,there were no significant variation among viability rate,ROS,mitochondrial membrane potential △Ψm and cell cycle in fluconazole-resistant strains,but a decrease of mitochondrial membrane potential △Ψm and viability rate,an increase of ROS accumulation were detected in a time-dose-dependent manner in fluconazole-susceptibile strains.A majority of Candida tropicalis were arrested in G2/M phase and apoptosis peak was seen.Free radicals scavenger glutathione inhibited ROS production,prevented G2/M arrest and decreased apoptosis in fluconazole-susceptibile strains.According to it,fluconazole maybe induce intracellular accumulation of ROS and decrease of mitochondrial membrane potential △Ψm,which could result in apoptosis of Candida tropicalis.