Benoxacor caused developmental and cardiac toxicity in zebrafish larvae

Mechanistic insights into the parental co-exposure of T-2 toxin and epoxiconazole on the F1 generation of zebrafish (Danio rerio)

Mycotoxins and pesticides frequently coexist in agricultural commodities on a global scale. The potential transgenerational consequences induced by these substances pose a significant threat to human health. However, there is a lack of data concerning the effects of co-contamination by these chemicals in the F1 generation following parental exposure. This investigation delved into the mixture effects of T-2 toxin (T-2) and epoxiconazole (EPO) on the offspring of zebrafish (Danio rerio). The findings revealed that exposure across generations to a combination of T-2 and EPO resulted in toxicity in the larvae of the F1 generation. This was demonstrated by a significant increase in the levels or activities of malondialdehyde (MDA), thyroxine (T4), Caspase3, and cas9, along with a decrease in the levels of cyp19a, ERα, and ERβ. These outcomes suggested that cross-generational exposure to T-2 and EPO in D. rerio disrupted oxidative balance, induced cell apoptosis, and affected the endocrine system. Moreover, these effects were magnified when the F1 generation was continuously exposed to these compounds. Notably, these adverse effects could persist in subsequent generations without additional exposure. This study underscored the potential dangers associated with the simultaneous presence of T-2 and EPO on the development of fish offspring and the resulting environmental hazards to aquatic ecosystems. These findings emphasized the significant health risks posed by cross-generational exposure and highlighted the need for additional legislative measures to address these concerns.

Chlorphoxim induces neurotoxicity in zebrafish embryo through activation of oxidative stress

It is known that chlorphoxim is a broad-spectrum and high-effective pesticide. With the wide use in agricultural practice, chlorphoxim residue is also frequently detected in water, but its potential toxicity to aquatic life is still unclear. In this study, zebrafish is used as a model to detect the toxicity of chlorphoxim. Our results showed that exposure of high concentration of chlorphoxim at 96 h post-fertilization (hpf) resulted in a high mortality and pericardium edema rate, a low hatchability rate and heart rate. The nervous system damage, swimming behavior alteration and acetylcholinesterase (AChE) inhibition were measured in zebrafish embryos after a 6 days post-fertilization (dpf) of chlorphoxim exposure. The expression of neural-related genes is abnormal in zebrafish embryos. Chlorphoxim exposure significantly increases oxidative stress in zebrafish embryos by inhibiting antioxidant enzyme (SOD and CAT) and activating reactive oxygen species (ROS). As expected, chlorphoxim exposure induces apoptosis by enhancing the expression of apoptotic genes (Bax, Bcl2, and p53). Astaxanthin (ATX), an effective antioxidant, was found to be able to rescue the neurotoxicity of chlorphoxim through relieving oxidative stress and apoptosis. Altogether, the results showed that chlorphoxim exposure led to severe neurotoxicity to zebrafish embryos, which was contributed to a more comprehensive understanding of the safety use of the organophosphorus pesticide.

Mechanisms regarding cardiac toxicity triggered by up-regulation of miR-144 in larval zebrafish upon exposure to triclosan

Although triclosan (TCS) is ubiquitously detected in environmental media and organisms, little information is available on its cardiotoxicity and underlying mechanisms. Herein, acute TCS exposure (0.69-1.73 μM) to zebrafish from embryos (6 hpf) to larvae (72 hpf) resulted in cardiac development defects, including increased angle between atrium and ventricle, prolonged SV-BA distance, linearized heart and pericardial cyst in 72-hpf larvae. These malformations resulted from interfered oxidative-stress pathways, reflecting in accumulated ROS and MDA and inhibited SOD and CAT activities. By RT-qPCR, the transcription levels of four cardiac development-related marker genes were significantly up-regulated except for gata4. Besides, miR-144 was identified as a regulatory molecule of TCS-induced cardiac defects by integrating analyses of artificial intervene expression and RNA-Seq data. Interestingly, the target genes of miR-144 were found and interacted with the above marker genes through constructing protein-protein interaction networks. After intervening the expression of miR-144 by microinjecting and activating Wnt pathway by an agonist BML-284, we confirmed that up-regulated miR-144 suppressed the expression of angiogenesis-related genes and negatively regulated Wnt pathway, further triggering angiogenesis disorders and cardiac phenotypic malformation. These findings unravel the underlying molecular mechanisms regarding TCS-induced cardiac development toxicity, and contribute to early warning and risk management of TCS.

Methyl Parathion Exposure Induces Development Toxicity and Cardiotoxicity in Zebrafish Embryos

Methyl parathion (MP) has been widely used as an organophosphorus pesticide for food preservation and pest management, resulting in its accumulation in the aquatic environment. However, the early developmental toxicity of MP to non-target species, especially aquatic vertebrates, has not been thoroughly investigated. In this study, zebrafish embryos were treated with 2.5, 5, or 10 mg/L of MP solution until 72 h post-fertilization (hpf). The results showed that MP exposure reduced spontaneous movement, hatching, and survival rates of zebrafish embryos and induced developmental abnormalities such as shortened body length, yolk edema, and spinal curvature. Notably, MP was found to induce cardiac abnormalities, including pericardial edema and decreased heart rate. Exposure to MP resulted in the accumulation of reactive oxygen species (ROS), decreased superoxide dismutase (SOD) activity, increased catalase (CAT) activity, elevated malondialdehyde (MDA) levels, and caused cardiac apoptosis in zebrafish embryos. Moreover, MP affected the transcription of cardiac development-related genes (vmhc, sox9b, nppa, tnnt2, bmp2b, bmp4) and apoptosis-related genes (p53, bax, bcl2). Astaxanthin could rescue MP-induced heart development defects by down-regulating oxidative stress. These findings suggest that MP induces cardiac developmental toxicity and provides additional evidence of MP toxicity to aquatic organisms.

5-HMF affects cardiovascular development in zebrafish larvae via reactive oxygen species and Wnt signaling pathways

5-Hydroxymethylfurfural (5-HMF) is a small molecule aldehyde compound produced by the Maillard reaction. As 5-HMF exists in a variety of foods and drugs and is easily ingested by humans, it has attracted extensive toxicological attention in recent years. Relevant research showed that 5-HMF has cytotoxicity, genotoxicity, and tumor effects. However, the cardiovascular effects of 5-HMF are unknown. To investigate the cardiovascular effects of 5-HMF in zebrafish, wild-type and transgenic embryos were treated with 10, 25, and 50 μg/mL of 5-HMF, followed by toxicological evaluation, histological observation, fluorescence observation, cell apoptosis staining, and gene quantitative analysis. High 5-HMF concentrations led to a significant increase in the heart rate and pericardial edema ratio, larger venous sinus-arterial bulb distance, more apoptosis of cardiac cells, cardiac linearization, defects in angiogenesis and cardiovascular development, and apoptosis-related gene expression disorders in zebrafish larvae. The abnormal phenotype caused by 5-HMF can be rescued by antioxidant N-acetyl-L-cysteine (NAC) and Wnt signaling pathway activator BML-284. It is inferred that high 5-HMF concentrations increased the level of reactive oxygen species, inhibited the transduction of the Wnt signaling pathway, and resulted in abnormal cardiovascular development in zebrafish larvae. This study provides a reference for understanding the mechanism of 5-HMF effects on cardiac development.