Effects of Chloramine T on zebrafish embryos malformations associated with cardiotoxicity and neurotoxicity

ABSTRACT

Chloramine T, a sodium p-toluene sulfonchloramide, is known to possess a wide spectrum of biocidal activity and is employed as a disinfectant in fish farms to treat bacterial infections. Although Chloramine T may effectively combat pathogens, the sublethal and lethal effects and changes in acetylcholinesterase (AChE) activity remain poorly elucidated using Danio rerio (zebrafish) embryos. Zebrafish is considered a model organism for toxicant screening research and exhibits mammalian-like physiological responses when exposed to environmental pollutants. The aim of this study was to (1) determine LC₅₀ of Chloramine T after 96 hr exposure, (2) verify disinfectant effects on developmental morphology, and (3) evaluate the disinfectant effects on AChE activity in zebrafish embryos. Chloramine T exposure was performed using 16, 32, 64, 128, or 256 mg/L concentrations. The mortality LC₅₀ values were 143.05 ± 3.11 and 130.97 ± 7.4 mg/L at 24 and 96 hr, respectively. Data demonstrated delayed hatching, reduced heartbeats, cardiac edema, and equilibrium disruption of hatched larvae throughout embryonic development. In addition, Chloramine T inhibited AChE activity at 64 or 128 mg/L after 96 hr treatment, corroborating the sub-lethality results observed in zebrafish embryo development and demonstrating an equilibrium disruption in zebrafish larvae.

GRAPHICAL ABSTRACT

KEYWORDS:

• Cardiotoxicity
• neurotoxicity
• Zebrafish
• disinfectants
• acetylcholinesterase
• fish embryo toxicity

Disclosure statement

No potential conflict of interest was reported by the author(s).

Authors’ contributions

CLGRW conceptualization, investigation, methodology, writing original draft, and review and editing. LGF investigation, methodology. ANS investigation, methodology. ILB investigation, methodology. JASJ investigation, methodology. ESA investigation, methodology. CEF conceptualization, methodology, formal analysis, resources, writing original draft, and review & editing. All authors read and approved the final manuscript.

Compliance with ethical standards

Ethics approval Animal handling followed the AVMA Guidelines for the Euthanasia of Animals:2020 Edition and procedures are in accordance to CONCEA (34/2017). All experimental procedures were approved by the Ethics Committee for the Experimental Use of Animals (CEUA nº 3.128/2021).

Data availability statement

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Additional information

Funding

This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001, and financed in part by the Fundação Universidade Federal de Mato Grosso do Sul – UFMS/MEC – Brazil; CEF has been continuously supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico (grant #310058/2010-1).