Yuan Cong, Li Meng, Zheng Yao, Zhou Ying, Wu Feili, Wang Zaizhao
College of Animal Science Technology, Northwest A&F University, Shaanxi Key Laboratory of Molecular Biology for Agriculture, Yangling, Shaanxi, 712100, China.
College of Animal Science Technology, Northwest A&F University, Shaanxi Key Laboratory of Molecular Biology for Agriculture, Yangling, Shaanxi, 712100, China.
Aquat Toxicol. 2017 Sep;190:174-180. doi: 10.1016/j.aquatox.2017.07.005. Epub 2017 Jul 11.
Hexavalent chromium (Cr) compounds are hazardous via all exposure routes. To explore the dynamics of Cr accumulation and elimination and to reveal the mechanisms underlying detoxification and antioxidation in juvenile Gobiocypris rarus, one-month old G. rarus larvae were exposed to 0.1mgL Cr for four weeks for accumulation and subsequently placed to clean water for another week for depuration. The contents of Cr were measured weekly in the whole body of G. rarus juveniles. The activities of catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD), glutathione S-transferase (GST) and glutathione reductase (GR), and contents of glutathione (GSH) and malonaldehyde (MDA), and transcripts of cat, Cu/Zn-sod, Mn-sod, gpx1, gstpi, gr, mt1, nrf2 and uba52 were determined. The results indicated that G. rarus juveniles had a strong ability to resist the Cr accumulation by Cr exposure and to remove Cr from the body in clean water. In addition, GST and MT proteins may be involved in the detoxification of Cr. Moreover, Cr-induced GST detoxification in G. rarus juveniles might be accomplished through the Nrf2-mediated regulation of gene expressions. The antioxidant enzyme systems exhibited a response mechanism of the protective enzymes in organisms when they are subjected to external environmental stress. Two weeks of Cr treatments could have led to the damage and consecutive degradation of antioxidant enzymes via ubiquitination, and MT proteins could be involved in protecting the activity of these enzymes. The capability of antioxidant enzyme systems to recover from the Cr-induced damage was strong in G. rarus juveniles after Cr was removed from the water.
六价铬（Cr）化合物通过所有暴露途径都具有危害性。为了探究稀有鮈鲫幼鱼体内铬积累和消除的动态过程，并揭示其解毒和抗氧化的潜在机制，将1月龄的稀有鮈鲫幼鱼暴露于0.1mg/L的铬中4周以进行积累，随后置于清洁水中再养1周以进行净化。每周测定稀有鮈鲫幼鱼全身的铬含量。测定过氧化氢酶（CAT）、谷胱甘肽过氧化物酶（GPx）、超氧化物歧化酶（SOD）、谷胱甘肽S -转移酶（GST）和谷胱甘肽还原酶（GR）的活性，以及谷胱甘肽（GSH）和丙二醛（MDA）的含量，还有cat、Cu/Zn - sod、Mn - sod、gpx1、gstpi、gr、mt1、nrf2和uba52的转录本。结果表明，稀有鮈鲫幼鱼具有很强的抵抗铬积累的能力，并且在清洁水中能将铬从体内排出。此外，GST和MT蛋白可能参与了铬的解毒过程。而且，稀有鮈鲫幼鱼中铬诱导的GST解毒可能是通过Nrf2介导的基因表达调控来实现的。抗氧化酶系统在生物体受到外部环境压力时表现出一种保护酶的响应机制。两周的铬处理可能通过泛素化导致抗氧化酶的损伤和连续降解，而MT蛋白可能参与保护这些酶活性。在水中的铬被去除后，稀有鮈鲫幼鱼的抗氧化酶系统从铬诱导的损伤中恢复的能力很强。
