Cadmium exposure reduces the density of a specific ionocyte subtype in developing zebrafish. (April 2020)

• Record Type: Journal Article
• Authors: Dave, Preeti H.; Kwong, Raymond W.M.
• Is Part Of: Chemosphere. Volume 244(2020)
• Publication Date: 2020-04
• Subjects: Cadmium -- Ionic regulation -- Ionocyte -- Zebrafish; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2019.125535
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: The present study examined the effects of waterborne cadmium (Cd) exposure on ionic balance and ionocyte density in developing zebrafish ( Danio rerio ) (0–4 days post-fertilization). Fish exposed to 1 or 10 μg Cd/L exhibited an increase in whole body Cd level. Exposure to 10 μg Cd/L also significantly reduced whole body content of Ca 2+, but not other major ions (e.g., Na +, K + and Mg 2+ ). Such reduction was accompanied by a decrease in the density of Ca 2+ -transporting ionocytes, the Na + /K + -ATPase-rich cells (NaRCs). However, the densities of other ionocyte subtypes (e.g., Na + -transporting ionocytes) remained unchanged after exposure to 10 μg Cd/L. The potential interactive effects between water chemistry and Cd exposure on ionocyte density were examined further in Cd-exposed larvae acclimated to different water NaCl or Ca 2+ levels. The results demonstrated that NaRC density increased in fish acclimated to low Ca 2+ water, presumably increasing Ca 2+ uptake for maintaining Ca 2+ homeostasis. However, Cd exposure completely abolished the increased NaRC density in low water Ca 2+ environments. The increased NaRCs over development was also reduced in Cd-exposed larvae. In conclusion, our study suggested that Cd exposure reduces the density of NaRCs and suppresses the compensatory regulation of NaRCs during acclimation to low water Ca 2+ level. These inhibitory effects by Cd exposure ultimately disrupt Ca 2+ balance in the early life stages of zebrafish. Graphical abstract: Image 1 Highlights: Early life stage of zebrafish is sensitive to Ca 2+ disruption by NOEC-range of Cd. Cd exposure specifically inhibits the development of Ca 2+ -transporting ionocytes. The compensatory regulation of Ca 2+ -transporting ionocytes is attenuated by Cd.