Environmentally relevant concentration of chromium activates Nrf2 and alters transcription of related XME genes in liver of zebrafish. (January 2019)

• Record Type: Journal Article
• Authors: Shaw, Pallab; Mondal, Paritosh; Bandyopadhyay, Arindam; Chattopadhyay, Ansuman
• Is Part Of: Chemosphere. Volume 214(2019)
• Page Start: 35
• Page End: 46
• Publication Date: 2019-01
• Subjects: Chromium -- Environmentally relevant -- Oxidative stress -- Hepatotoxicity -- Nrf2 -- Zebrafish; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2018.09.104
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Fish is an excellent model to decipher the mechanism of toxicity of aquatic contaminants such as hexavalent chromium (Cr [VI]). The present study looked into the manifestation of stress in liver of zebrafish exposed to an environmentally relevant concentration (2 mgL −1 ), and the functioning of the cytoprotective machinery that pacifies the formed stress. The results lead us to hypothesize that oxidative stress plays a key role in chromium-induced toxicity resulting in lipid peroxidation and extensive changes in tissue ultrastructure. In treated fish, production of reactive oxygen species, increase in reduced glutathione content and increase in malondialdehyde content along with enhanced catalase activity were evident. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) was found to increase both at transcriptional and translational level and its translocation into the nucleus was confirmed by fluorescence-based immunohistochemical studies. The mRNA levels of genes like Nqo1, Cyp1a and Cu/Zn Sod were found to increase whereas Ho1, Hsp70 and Ucp2 were down-regulated. The sensitivity of these genes towards Cr [VI] validates their candidature as important biomarkers of Cr [VI] exposure in zebrafish. Graphical abstract: Image Highlights: Environmentally relevant concentration of Cr [VI] generates ROS in zebrafish liver. Elevated CAT activity, MDA content and GSH content confirm oxidative stress. Histopathological analysis confirms alteration in liver histoarchitecture. Activation and translocation of Nrf2 into the nucleus of zebrafish hepatocytes. Increased expression of Nqo1, Cu/Zn Sod and Cyp1a aids in cytoprotection.