Neburon induced cardiotoxicity in embryonic and adult male zebrafish via over-activation of the Ahr-Notch1 signaling pathway.

Neburon is a phenylurea herbicide that is mainly used in the growth of crops such as wheat. It may accumulate through the food chain and harm the health of organisms and even humans. However, there are limited studies on its toxicity, especially in terms of cardiac health. This study employed acute neburon exposure (early developmental stage) and chronic neburon exposure (full life cycle) to assess its cardiac effects across distinct life stages in zebrafish. Exposure to 0.1 μg/L, 1 μg/L, and 10 μg/L neburon for 72 h caused dose-dependent increases in cardiac malformations, heart rate, and decreased cardiac function, with significant effects at 10 μg/L. When exposure was extended through to adulthood (150 days) under the same concentration gradient, even the lowest dose (0.1 μg/L) induced significant increases in ventricular cavity size, average ventricular wall thickness, and fibrosis levels in male zebrafish. Additionally, heart body ratio and myocardial density decreased dose-dependently, with notable changes at 1 μg/L and 10 μg/L. Mechanistic investigations revealed that neburon-induced cardiotoxicity likely involved aryl hydrocarbon receptor (Ahr) nuclear translocation, over-activation of Notch (Drosophila) homolog 1 (Notch1) signaling, and suppression of critical downstream genes, such as bone morphogenetic protein 10 (bmp10), neuregulin-1-human epidermal growth factor receptor 2 (nrg1-erbb2), and ephrin b2 (efnb2a), which were essential for cardiomyocyte proliferation and trabecular development. Moreover, co-exposure of zebrafish embryos to neburon with the Ahr antagonist CH223191 or the Notch1 inhibitor DAPT during the embryonic stage demonstrated significant rescue effects on cardiac malformation rates, heart rate, and cardiac function. This study provided new insights into neburon-induced cardiotoxicity, offering valuable data for understanding pollutant-related cardiac diseases.