Burdon R H, Gill V, Rice-Evans C
Department of Bioscience & Biotechnology, Todd Centre, University of Strathclyde, Glasgow, UK.
Free Radic Res Commun. 1993;18(6):369-80. doi: 10.3109/10715769309147503.
Experiments have been carried out to explore the use of a tetrazolium salt, MTT(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide in the detection of intracellularly generated superoxide in HeLa cells. From the use of a low molecular weight lipophilic mimic of superoxide dismutase, as well as superoxide dismutase, and inhibitors of superoxide dismutase, it is suggested that at least 20-30% of the intracellular reduction of MTT is due to superoxide. Whilst this may arise from mitochondria another possible intracellular source in HeLa cells may be xanthine oxidase. The overall rate of intracellular MTT reduction in HeLa cells is inversely dependent on levels of serum in the culture medium. Serum components with a modulatory role in this context are those with antioxidant function. Reduced MTT is also detectable extracellularly in cultures of HeLa cells and at least 80% of this is due to superoxide. Use of inhibitors suggest that whilst a small proportion (30%) may arise through an NADPH-oxidase type enzyme, other sources of extracellular superoxide in HeLa cells remain a possibility.
已经开展了实验，以探索使用四氮唑盐MTT（3-(4,5-二甲基噻唑-2-基)-2,5-二苯基溴化四氮唑）检测HeLa细胞内产生的超氧化物。通过使用超氧化物歧化酶的低分子量亲脂性模拟物、超氧化物歧化酶本身以及超氧化物歧化酶抑制剂，表明MTT在细胞内的还原中至少20%-30%是由超氧化物引起的。虽然这可能源于线粒体，但HeLa细胞中另一个可能的细胞内来源可能是黄嘌呤氧化酶。HeLa细胞内MTT还原的总体速率与培养基中的血清水平呈负相关。在这种情况下具有调节作用的血清成分是那些具有抗氧化功能的成分。在HeLa细胞培养物的细胞外也可检测到还原型MTT，其中至少80%是由超氧化物引起的。抑制剂的使用表明，虽然一小部分（30%）可能通过NADPH氧化酶类型的酶产生，但HeLa细胞中细胞外超氧化物的其他来源仍然是可能的。
