Effects of two different pesticides (acrolein and fonofos) on heart development in zebrafish (Danio rerio)

Zebrafish (Danio rerio) has a good reputation for being an attractive model organism for developmental and toxicological research. In this study, zebrafish embryos were exposed to acrolein (herbicide) and fonofos (insecticide) to examine the cardiotoxic effects. Developmental toxicity was also evaluated. The 96 h LC50 values of acrolein and fonofos were determined as 654.385 µg/L and 7.067 mg/L, respectively. Then, the embryos were treated with 1, 4, 16, 64, 256 µg/L acrolein and 0.25, 0.5, 1, 2, 4 mg/L fonofos for 96 h. Embryos were examined at 48, 72 and 96 hpf. Both of the pesticides affected the development and cardiac morphology and function of the embryos. Sinus venosus-bulbus arteriosus (SV-BA) distance of 64, 256 µg/L acrolein and 2, 4 mg/L fonofos groups were elongated compared to the control samples. Immunostaining with MF20 antibody exhibited that the atrium positioned clearly posterior to the ventricle which indicated that the cardiac looping was inhibited. Heart wall structure were altered histologically. Acrolein-induced increased heart rate was observed in 4, 16, 64 and 256 µg/L treatment groups while fonofos caused decreased heart rate only at 4 mg/L. In conclusion, developing heart of zebrafish is a target for acrolein and fonofos. However, the certain mechanisms are currently unknown and further studies are required.