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.