摘要
目的:探索大黄素提高新生隐球菌（cryptococcus neoformans，C. neoformans）琥珀酸脱氢酶（succinate dehydrogenase，SDH）活性，增强氧化作用，阐述大黄素新的生物学功能，提高以SDH为靶点的抗菌药物的敏感性，发挥协同抗菌作用，缓解临床耐药的严重问题。方法:用微量肉汤稀释法和MTT法检测大黄素对C. neoformans的最小抑菌浓度（minimum inhibitory concentration，MIC），并检测大黄素诱导后C. neoformans的活性氧（reactive oxygen species，ROS）和线粒体膜电位的变化，qPCR检测SDH mRNA的表达，用表面等离子共振方法检测大黄素与SDH的相互作用。结果:大黄素无明显的抑制C. neoformans作用，MIC＞256 μg/ml，但1~4 μg/ml的大黄素可以促进C. neoformans的SDH活性升高，1 μg/ml时ROS升高和SDH的mRNA表达也明显增强，大黄素与SDH可发生特异性结合。结论:大黄素具有促进C. neoformans的SDH活性升高、增强ROS作用的新生物学功能。
Abstract
Objective:To explore the effects of emodin on succinate dehydrogenase (SDH) activity and oxidation in Cryptococcus neoformans (C. neoformans) and elaborate the new biological function of emodin, so as to improve the sensitivity of antibacterial drugs targeting SDH and alleviate the serious problem of drug resistance.Methods:The minimal inhibitory concentration of emodin against C. neoformans was detected by broth microdilution and MTT assay, and the changes of reactive oxygen species (ROS) and mitochondrial membrane potential of C. neoformans treated with emodin were detected. The expression of SDH mRNA was detected by qPCR, and the interaction between emodin and SDH was detected by surface plasmon resonance.Results:Emodin had no obvious inhibitory effects on C. neoformans, with an MIC＞256 μg/ml, but emodin at a concentration of 1~4 μg/ml was able to promote the SDH activity of C. neoformans. At 1 μg/ml, emodin significantly increased the ROS and SDH mRNA expression. Emodin can bind with SDH specifically.Conclusion:Emodin can promote the SDH activity and enhance ROS production in C. neoformans, which represents the new biological function of emodin.
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