Ramírez-Duarte Wilson F, Kurobe Tomofumi, Teh Swee J
Department of Anatomy, Physiology, and Cell Biology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
Department of Anatomy, Physiology, and Cell Biology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
Comp Biochem Physiol C Toxicol Pharmacol. 2017 Aug;198:37-44. doi: 10.1016/j.cbpc.2017.05.003. Epub 2017 May 18.
Increasing aluminum (Al) concentrations in aquatic habitats as a result of anthropogenic acidification and industrialization is a global issue. Moreover, in extensive areas of the humid tropics and subtropics, high Al concentrations in freshwater are observed because of both naturally low pH and high Al concentrations in soil. Al increases production of reactive oxygen species and enhances oxidative damage in mammals. However, no studies have examined the effect of environmentally relevant concentrations of Al at low pH on oxidative stress in fish. This study assessed Al-induced effects on enzymatic and non-enzymatic antioxidants, lipid peroxidation, and on expression of oxidative stress-related genes at low pH using Japanese Medaka (Oryzias latipes). Larval fish were exposed to dissolved Al concentrations of 0, 1.7, 6.2 and 16.7μgL for 4days at pH5.3 in soft water. Al caused a significant reduction in activity of glutathione peroxidase at 6.2 and 16.7μgL, and of glutathione reductase at 16.7μgL in whole body homogenates. No changes were observed in the expression of the glutathione peroxidase gene, and expression levels of the glutathione reductase gene were too low to be quantitated. Even though there was an overall decrease in the activity of catalase and in the concentration of glutathione, differences were not significant compared to the control. Changes in lipid peroxidation were not found. This study showed that exposure to environmentally relevant concentrations of Al at low pH impairs antioxidant defense mechanisms of Medaka.
由于人为酸化和工业化，水生栖息地中铝（Al）浓度不断增加是一个全球性问题。此外，在潮湿热带和亚热带的广大地区，由于自然低pH值和土壤中高铝浓度，淡水中铝浓度也很高。铝会增加哺乳动物体内活性氧的产生并加剧氧化损伤。然而，尚无研究考察低pH环境相关浓度的铝对鱼类氧化应激的影响。本研究使用日本青鳉（Oryzias latipes）评估了低pH条件下铝对酶促和非酶促抗氧化剂、脂质过氧化以及氧化应激相关基因表达的影响。幼鱼在软水pH5.3条件下暴露于0、1.7、6.2和16.7μg/L的溶解铝浓度中4天。铝导致全身匀浆中6.2和16.7μg/L浓度下谷胱甘肽过氧化物酶活性显著降低，以及16.7μg/L浓度下谷胱甘肽还原酶活性显著降低。谷胱甘肽过氧化物酶基因表达未观察到变化，谷胱甘肽还原酶基因表达水平过低无法定量。尽管过氧化氢酶活性和谷胱甘肽浓度总体下降，但与对照组相比差异不显著。未发现脂质过氧化的变化。本研究表明，在低pH条件下暴露于环境相关浓度的铝会损害青鳉的抗氧化防御机制。
