细胞应激条件下嗜热四膜虫线粒体膜电位变化研究

Loss of Mitochondrial Membrane Potential Induces the Accumulation of ROS in Tetrahymena thermophila Under Cellular Stress

单细胞线虫纲原生动物四膜虫(Tetrahymena),在H2O2的诱导下可发生凋亡样死亡.另外,最新研究表明细胞中活性氧簇(ROS)的积累可有效地诱导细胞自噬途径的发生.通过流式细胞技术和荧光显微技术,检测了经饥饿和ROS诱导剂处理后,线粒体内膜电位变化及细胞内ROS的积累.此外,应用两种抗氧化剂氮乙酰半胱氨酸(NAC)和过氧化氢酶(Catalase)分别对四膜虫细胞进行处理,检测了在氧化应激条件下的抗氧化作用效果.结果表明,Oligomycin和Menadione可有效抑制线粒体膜电位的维持,从而导致细胞内ROS积累.同时,H2O2处理和饥饿处理可以导致嗜热四膜虫细胞线粒体膜电位丧失以及细胞质ROS积累.另外,N-acetylcystine和Catalase可有效地降低四膜虫细胞内ROS的积累,以及保持四膜虫细胞线粒体内膜电位,维持通透性.

The unicellular eukaryotic protozoan Tetrahymena undergoes apoptotic-like cell death in response to oxidative stress. In addition, it has been well-accepted that the accumulation of ROS induces autophagy and cell death in higher organisms. Here, the flow cytometry and fluorescence microscopy results revealed that the inner mitochondrial membrane potential was changed and intracellular ROS accumulated after stimulated by starvation or ROS inducers. The antioxidant effects under oxidative stress conditions by treating Tetrahymena cells with two antioxidants （N-acetylcystein or Catalase） was also examined. The results showed that oxidative stimulation can cause loss of mitochondrial membrane potential and cytoplasmic ROS accumulation in Tetrahymena thermophila, whereas N-acetylcystein or Catalase pretreatment maintains the integrity and permeability of the inner mitochondrial membrane and reduces the accumulation of ROS in Tetrahymena.