Involvement of Nrf2-HO-1/JNK-Erk Signaling Pathways in Aconitine-Induced Developmental Toxicity, Oxidative Stress, and ROS-Mitochondrial Apoptosis in Zebrafish Embryos.

Qing Xia,Zhenzhen Song,Shuo Gao,Kechun Liu,Pengfei Tu,Samuel Rajendran Rapael Gnanamuthu,Xue Wang,Kaiyan Zhuang,Yun Zhang,Jianheng Li

doi:10.3389/fphar.2021.642480

Abstract

Aconitine (AC), one of the bioactive diterpenoid alkaloids extracted from Aconitum plants, is widely used in traditional herbal medicine to treat various diseases. Emerging evidence indicates that AC has attracted great interest for its wide cardiotoxicity and neurotoxicity. However, the toxic effects of AC on embryonic development and its underlying mechanisms remain unclear. Here, a developmental toxicity assay of AC was performed on zebrafish embryos from 4 to 96 h post fertilization (hpf), and its underlying mechanisms were discussed. AC exposure impaired the cardiac, liver, and neurodevelopment. Especially, a high dose of AC (7.27 and 8.23 μM) exposure resulted in malformations at 72 and 96 hpf, including reduced body length, curved body shape, pericardial edema, yolk retention, swim bladder and brain developmental deficiency, and degeneration of dopaminergic neurons. High-concentration AC exposure caused a deficient cardiovascular system with cardiac dysfunctions, increased heart rates at 72 and 96 hpf, and reduced locomotor behavior at 120 hpf. AC treatment significantly increased the ROS level and triggered cell apoptosis in the heart and brain regions of embryos at 96 hpf in 7.27 and 8.23 μM AC treatment zebrafish. Oxidative stress was confirmed by reduced levels of T-SOD activity associated with accumulation of lipid peroxidation in larvae. The expression levels of oxidative stress-related genes (Nrf2, HO-1, Cat, and Sod-1) Erk1/2 and Bcl-2 were significantly downregulated at 96 hpf. The expression pattern of JNK and mitochondrial apoptosis-related genes (Bad, Bax, Cyto C, Casp-9, and Casp-3) was significantly upregulated. Taken together, all these parameters collectively provide the first evidence of AC-induced developmental toxicity in zebrafish embryo/larvae through ROS-medicated mitochondrial apoptosis involving Nrf2/HO-1 and JNK/Erk pathways.

Highlights

Aconitum plants are commonly known as monkshood and widely distributed all over the world
In the developmental toxicity assay, we found AC induced significant morphological phenotypes, most prominently yolk retention, swim-bladder deficiency, pericardial edema, and curved body shape, in a dosedependent manner (Figures 1B,E)
Further studies showed that the generation of ROS, oxidative stress, and subsequent activation of mitochondrial apoptosis mediated by nuclear factor erythroid 2-related factor (Nrf2)/heme oxygenase-1 (HO-1) and Jun NH2-terminal kinase (JNK)/Erk signaling pathways might be the underlying mechanism of the developmental toxicity induced by AC

Summary

Introduction

Aconitum plants are commonly known as monkshood and widely distributed all over the world It has been used as a traditional medicine to treat shock caused by acute myocardial infarction, coronary heart disease, and angina pectoris in China (Singhuber et al, 2009; Zhou et al, 2015; Chan, 2016; Liu et al, 2017). Liu et al reported that AC induced cardiotoxicity and apoptosis in embryonic zebrafish by influencing the expression of cardiovascular relative genes, such as Tbx, Gata, and Nkx2.5 (Liu et al, 2019). Wang et al found that AC-induced cardiotoxicity in zebrafish predominantly included arrhythmias, extended sinus venous and bulbus arteriosus (SV-BA) distance, and larger pericardial edema aera (Wang et al, 2020). A more detailed assessment of the developmental toxicity and underlying mechanisms of AC is required

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