PUBLICATION
Neurotoxic pesticides change respiratory parameters in early gill-breathing, but not in skin-breathing life-stages of zebrafish (Danio rerio)
- Authors
- Kämmer, N., Reimann, T., Braunbeck, T.
- ID
- ZDB-PUB-240121-4
- Date
- 2024
- Source
- Aquatic toxicology (Amsterdam, Netherlands) 267: 106831106831 (Journal)
- Registered Authors
- Braunbeck, Thomas
- Keywords
- Breathing amplitude, Breathing frequency, Fish early life-stages, Neurotoxicity, Respirometry
- MeSH Terms
-
- Aldicarb
- Aniline Compounds
- Animals
- Chlorpyrifos*/toxicity
- Embryo, Nonmammalian
- Fluoxetine
- Gills
- Larva
- Oxygen
- Permethrin
- Pesticides*
- Respiration
- Respiratory Insufficiency*
- Toxicity Tests, Acute
- Water Pollutants, Chemical*/toxicity
- Zebrafish/physiology
- PubMed
- 38244448 Full text @ Aquat. Toxicol.
Citation
Kämmer, N., Reimann, T., Braunbeck, T. (2024) Neurotoxic pesticides change respiratory parameters in early gill-breathing, but not in skin-breathing life-stages of zebrafish (Danio rerio). Aquatic toxicology (Amsterdam, Netherlands). 267:106831106831.
Abstract
Neurotoxic compounds can interfere with active gill ventilation in fish, which might lead to premature death in adult fish, but not in skin-breathing embryos of zebrafish, since these exclusively rely on passive diffusion across the skin. Regarding lethality, this respiratory failure syndrome (RFS) has been discussed as one of the main reasons for the higher sensitivity of adult fish in the acute fish toxicity test (AFT), if compared to embryos in the fish embryo toxicity test (FET). To further elucidate the relationship between the onset of gill respiration and death by a neurotoxic mode of action, a comparative study into oxygen consumption (MO2), breathing frequency (fv) and amplitude (fampl) was performed with 4 d old skin-breathing and 12 d old early gill-breathing zebrafish. Neurotoxic model substances with an LC50 FET/AFT ratio of > 10 were used: chlorpyrifos, permethrin, aldicarb, ziram, and fluoxetine. Exposure to hypoxia served as a positive control, whereas aniline was tested as an example of a narcotic substance interfering non-specifically with gill membranes. In 12 d old larvae, all substances caused an increase in MO2, fv and partly fampl, whereas effects were minor in 4 d old embryos. An increase of fv in 4 d old embryos following exposure to chlorpyrifos, aldicarb and hypoxia could not be correlated with an increased MO2 and might be attributed either to (1) to the successfully postponed decrease of arterial partial pressure of oxygen (PO2) through support of skin respiration by increased fv, (2) to an unspecific stimulation of the sphincter muscles at the base of the gill filaments, or (3) to the establishment of oxygen sensing for later stages. In gill-breathing 12 d old zebrafish, a concentration-dependent increase of fv was detected for aniline and chlorpyrifos, whereas for aldicarb, fluoxetine and permethrin, a decline of fv at higher substance concentrations was measured, most likely due to the onset of paralysis and/or fatigue of the gill filament sphincter muscles. Since alterations of fv serve to postpone the decrease in arterial PO2 and MO2 increased with decreasing fv, the respiratory failure syndrome could clearly be demonstrated in 12 d old zebrafish larvae. Passive respiration across the skin in zebrafish embryos could thus be confirmed as a probable reason for the lower sensitivity of early life-stages to neurotoxicants. Integration of respiratory markers into existing testing protocols with non-protected developmental stages such as embryos might help to not underestimate the toxicity of early life-stages of fish.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping