The Effects of Carbaryl on the Development of Zebrafish (Danio rerio) Embryos

Abstract

In the United States, Sevin TM brand insecticide is one of the most commonly used insecticides. The active ingredient in Sevin TM , carbaryl (1-napthyl-N-methylcarbamate), is a known acetylcholinesterase (AChE) inhibitor that prevents the breakdown of acetylcholine to acetate and choline at the synapse. While carbaryl successfully causes the death of insects by paralysis, it has also been shown to have negative effects on the development of several nontarget species. To study the effects of carbaryl on nontarget species, zebrafish (Danio rerio) were used, as they are a good model for both toxicology and development studies. Our study suggests that carbaryl induces changes in morphology, specifically in embryo size and shape. Additionally, carbaryl causes defects in heart formation that is characterized by a decrease in heart rate and a developmental delay/defect in cardiac looping. A significant decrease in the number of spinal cord neurons present was also observed. Further investigation showed that there was an increase in cell death in carbaryl-treated embryos. The results indicate that carbaryl may have a greater environmental impact than initially intended. Our study, which was conducted solely by undergraduates at a liberal arts college, indicates that carbaryl may be detrimental to the development of nontarget species.

Zebrafish as a Vertebrate Model System to Evaluate Effects of Environmental Toxicants on Cardiac Development and Function

“…Similar to chronic exposure, acute exposure of 100 µg/mL carbaryl for 10 min reduced the heart rate of embryos. Other studies, including a more recent study, showed heart malformation effects of zebrafish carbaryl exposure [87]. The fungicide paclobutrazol exposure during development also reduced heart rate, but the reduction may be associated to the paclobutrazol-induced defective heart structure [77].…”

Evaluation of cytotoxicity and genotoxicity of insecticide carbaryl to flounder gill cells and its teratogenicity to zebrafish embryos

“…The AChE inhibitory ability of the toxicant may induce the lowering of heart action. Such effects were also exhibited when exposed to zebrafish, medaka and killifish (Kashiwada et al, 2008;Lin et al, 2007;Schock et al, 2012;Solomon and Weis, 1979;Weis and Weis, 1974), but the effects can be toxicant-and concentration-specific. Lin et al (2007) also suggested that besides inhibition of the AChE, carbaryl may work via inhibition of calcium ion channels to induce bradycardia along with other alternate mechanisms.…”

“…Carbaryl is not persistent in environment but is more stable in seawater than in freshwater (Pelletier et al, 2006;Xu, 2000). Its wide use also increased the risk of being leached into groundwater thus imposing adverse effects on human health (Schock et al, 2012;Todd and van Leeuwen, 2002).…”

“…Several studies have been carried out on the developmental toxicity of carbaryl to zebrafish embryo. Carbaryl exposure retarded embryonic development, delayed hatching, defect in heart formation, red blood cell accumulation, bradycardia and decreased embryo size in zebrafish at non-lethal concentrations (Lin et al, 2007;Schock et al, 2012;Todd and van Leeuwen, 2002). But further global investigations of the developmental and teratogenic toxicity of carbaryl to izebrafish embryos are still needed for the safety assessment of carbaryl for aquatic organisms.…”

Zebrafish: A Marvel of High-Throughput Biology for 21st Century Toxicology

“…Taking advantage of the zebrafish’s external and transparent development, the zebrafish embryo model has been exploited in a wide array of developmental toxicology studies, including skeletal development (46, 47), immune development (48), neurodevelopment (49, 50), cardiovascular development (51–53), and regeneration (54–57). A recent spate of screens have used the zebrafish embryo model to analyze potential developmental toxicity of small molecule libraries previously uncharacterized in in vivo models (44); unknown contaminants in landfill soil (58); nanomaterials (reviewed in Fako and Ferguson (59)); and ototoxic drugs (60).…”