Modulations of TCDD-mediated induction of zebrafish cyp1a1 and the AHR pathway by administering Cd2+in vivo

Identification of competing endogenous RNA networks associated with circRNA and lncRNA in TCDD-induced cleft palate development

2,3,7,8 -tetrachlorodibenzo-p-dioxin (TCDD) is a teratogen that can induce cleft palate formation, a common birth defect. Competing endogenous RNAs (ceRNAs), including circular RNAs (circRNAs) and long non-coding RNAs (lncRNAs), indirectly regulate gene expression via sharing microRNAs (miRNAs). Nevertheless, the mechanism by which they act as ceRNAs to regulate palatal development remains to be explored in greater detail. Here, the cleft palate model of C57BL/6 N pregnant mice was constructed by gavage of TCDD (64 ug/kg) on gestation day (GD) 10.5, and the palatal shelves were taken on gestation day (GD) 14.5 for whole-transcriptome sequencing to investigate the underlying mechanisms of the roles of circRNAs and lncRNAs as ceRNAs in cleft palate. Sequencing results revealed that 293 lncRNA, 589 circRNA, 47 miRNA, and 138 messenger RNA (mRNA) were significantly dysregulated, and the cytochrome P450 (CYP) enzymes and the aryl hydrocarbon receptor (AhR) pathway play key roles in the induction of cleft palate upon exposure to TCDD. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed the function of TCDD function was mainly related to the metabolic processes of intracellular compounds, including the metabolic processes of cellular aromatic compounds and the metabolism of exogenous drugs by cytochrome P450, etc. Furthermore, quantitative reverse transcription polymerase chain reaction (qRT-PCR) indicated that the circRNA_1781/miR-30c-1-3p/PKIB and XR_380026.2/miR-1249-3p/DNAH10 ceRNA networks were hypothesized to be a hub involved in palatal development suggesting that the circRNA_1781/miR-30c-1-3p/PKIB and XR_380026.2/miR-1249-3p/DNAH10 ceRNA networks may be critical for palatogenesis, setting the foundation for the investigation of cleft palate.

Hepatic transcriptome, transcriptional effects and antioxidant responses in Poecilia vivipara exposed to sanitary sewage

Aquatic environments are subject to threats from multiple human activities, particularly through the release of untreated sanitary sewage into the coastal environments. These effluents contain a large group of natural or synthetic compounds referred to as emerging contaminants. Monitoring the types and quantities of toxic substances in the environment, especially complex mixtures, is an exhausting and challenging task. Integrative effect-based tools, such as biomarkers, are recommended for environmental quality monitoring programs. In this study, fish Poecilia vivipara were exposed for 24 and 96 h to raw untreated sewage diluted 33 % (v/v) in order to identify hepatic genes to be used as molecular biomarkers. Through a de novo hepatic transcriptome assembly, using Illumina MiSeq, 54,285 sequences were assembled creating a reference transcriptome for this guppy species. Transcripts involved in biotransformation systems, antioxidant defenses, ABC transporters, nuclear and xenobiotic receptors were identified and evaluated by qPCR. Sanitary sewage induced transcriptional changes in AhR, PXR, CYP2K1, CYP3A30, NQO1, UGT1A1, GSTa3, GSTmu, ST1C1, SOD, ABCC1 and SOX9 genes from liver of fish, particularly after 96 h of exposure. Changes in hepatic enzyme activities were also observed. The enzymes showed differences in fish exposed to both periods, while in the gills there was a prevalence of significant results after 96 h. The observed differences were associated to gender and/or to sewage exposure. The obtained results support the use of P. vivipara as sentinel and model organism for ecotoxicological studies and evidence the importance of understanding the differential responses associated to gender.

An integrative data-centric approach to derivation and characterization of an adverse outcome pathway network for cadmium-induced toxicity

Cadmium is a prominent toxic heavy metal that contaminates both terrestrial and aquatic environments. Owing to its high biological half-life and low excretion rates, cadmium causes a variety of adverse biological outcomes. Adverse outcome pathway (AOP) networks were envisioned to systematically capture toxicological information to enable risk assessment and chemical regulation. Here, we leveraged AOP-Wiki and integrated heterogeneous data from four other exposome-relevant resources to build the first AOP network relevant for inorganic cadmium-induced toxicity. From AOP-Wiki, we filtered 309 high confidence AOPs, identified 312 key events (KEs) associated with inorganic cadmium from five exposome-relevant databases using a data-centric approach, and thereafter, curated 30 cadmium relevant AOPs (cadmium-AOPs). By constructing the undirected AOP network, we identified a large connected component of 18 cadmium-AOPs. Further, we analyzed the directed network of 59 KEs and 82 key event relationships (KERs) in the largest component using graph-theoretic approaches. Subsequently, we mined published literature using artificial intelligence-based tools to provide auxiliary evidence of cadmium association for all KEs in the largest component. Finally, we performed case studies to verify the rationality of cadmium-induced toxicity in humans and aquatic species. Overall, cadmium-AOP network constructed in this study will aid ongoing research in systems toxicology and chemical exposome.

2,2',4,4'-Tetrabromodiphenyl ether and cadmium co-exposure activates aryl hydrocarbon receptor pathway to induce ROS and GSDME-dependent pyroptosis in renal tubular epithelial cells

We have previously found that a mixture exposure of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) and cadmium (Cd) causes kidney damage; however, the mechanism was not fully understood. The aryl hydrocarbon receptor (AhR) is a ligand-receptor transcription factor that plays an important role in the adaptive response or metabolic detoxification of environmental toxins. Thus, this study aimed to examine the role of AhR in kidney toxicity. BDE-47 (50 μM) or Cd (5 μM) exposure reduced cell viability in renal tubular epithelial cells (HKC), with a larger effect observed in co-treatment. The cell morphology presented pyroptotic changes, including swollen cells, large bubbles, and plasma membrane pore formation. The gene expressions of AhR, heat shock protein 90 (Hsp90), AhR nuclear translocator (ARNT), and cytochrome P450 1B1 (CYP1B1) were increased, while CYP1A1 was decreased. Reactive oxygen species (ROS) were generated, which was reduced by the AhR antagonist CH223191. The apoptosis, necrosis, and intracellular lactated hydrogenase (LDH) release was elevated, and this was attenuated by N-acetylcysteine (NAC). Furthermore, the pyroptosis pathway was activated with increased protein levels of cleaved-caspase-3 and gasdermin E N-terminal (GSDME-NT), while caspase-8, caspase-3, and GSDME were decreased. These effects were alleviated by NAC and CH223191. Our data demonstrate a combined effect of BDE-47 and Cd on nephrotoxicity by activating AhR to induce ROS contributing to GSDME-dependent pyroptosis, and retardation of the AhR pathway could reduce this toxicity.

Toxicity and ecological risk assessment for two AhR agonistic pesticides mepanipyrim and cyprodinil and their metabolites

Mepanipyrim and cyprodinil are widely used to control and/or prevent fungal diseases in fruit culture. They are frequently detected in the aquatic environment and some food commodities. Different from TCDD, mepanipyrim and cyprodinil are more easily metabolised in the environments. However, the risk of their metabolites to the ecological environment is unclear and needs to be further confirmed. In this study, we investigated the temporal pattern of mepanipyrim- and cyprodinil-induced CYP1A and AhR2 expression and EROD enzyme activity at different time frames during zebrafish embryonic and larval development. Then, we assessed the ecological risk of mepanipyrim, cyprodinil, and their metabolites to aquatic organisms. Our results showed that mepanipyrim and cyprodinil exposure could increase the expression level of cyp1a and ahr2 genes and EROD activity by a dynamic pattern in different developmental stages of zebrafish. Besides, their several metabolites showed strong AhR agonistic activity. Importantly, these metabolites could cause potential ecological risks to aquatic organisms and should be paid more attention to. Our results would provide an important reference value for environmental pollution control and the use management of mepanipyrim and cyprodinil.

Transcriptome sequencing reveals improved ammonia nitrogen tolerance in Zebra II strain of the Manila clam Ruditapes philippinarum

In this research, we identified genes associated with ammonia nitrogen (TAN) stress response and resistance in juveniles of the Zebra II strain and a wild population of the Manila clam Ruditapes philippinarum. Both groups were subjected to a 96 h acute toxicity test using TAN concentrations of 17.617 ± 0.634 and 16.670 ± 0.7 mg/l, respectively. We then collected samples, conducted transcriptome sequencing and screened the sequences for differentially expressed genes (DEGs) related to TAN stress response. We identified 2908 and 2861 DEGs in the Zebra II and wild clam groups, respectively, and the two groups had 626 DEGs in common. The verified DEGs had less of a detoxification effect in the wild population than that in the Zebra II group. Gene Ontology database analysis showed that Zebra II juveniles were mainly enriched in protein phosphorylation, purine nucleoside binding, and kinase activity, whereas the wild population juveniles were primarily enriched in oxidases activity, organic acid metabolic processes, and extracellular regions. Kyoto Encyclopedia of Genes and Genomes pathway analysis mainly highlighted aminoacyl tRNA biosynthesis in Zebra II juveniles and sphingolipid metabolism, FOXO signaling, biosynthesis of aminoacyl tRNA, and other pathways in the wild population. These results show that the toxic effect of TAN on the Manila clam is related to a variety of pathways, which are mainly related to immune response, inflammatory response, metabolic pathways, and nerve conduction. This study provides basic data and theoretical reference for revealing the molecular regulation mechanism of the improved TAN tolerance of Zebra II strain as compared with the wild population of Ruditapes philippinarum.

The mechanisms of aluminum-induced immunotoxicity in chicks

Aluminum (Al) is a ubiquitous environmental pollutant representing a significant global health hazard to human and animal health, including chicks. Al toxicity causes oxidative stress, leading to tissue injury, and consequently causes various diseases. NRF2 signaling is vital for protecting cells against oxidative stress. Nuclear xenobiotic receptors are activated by exogenous toxins, thereby inducing the transcription of cytochrome P450 enzyme systems (CYP450s) isoforms involved in xenobiotic metabolism and transport. However, little is known about Al-induced oxidative stress, nuclear xenobiotic receptors and fibrosis in chicks and the mechanisms involved. In this study, male chicks were treated with 0 mg/kg and 500 mg/kg Al₂(SO₄)₃ to evaluate the mechanisms for Al-induced immunotoxicity. Histopathology revealed pathological injury, fibrin aggregation, disruption of the Nuclear Xenobiotic Receptors, and alteration of CYP450s homeostasis in Al-treated chicks due to oxidative stress. Notably, regulation of the NRF2 pathway and CYP450s and fibrosis-related genes was found to play a vital role in inhibiting immunotoxicity. This study provides new insights regarding the mechanisms of Al-induced immunotoxicity, including activation of the nuclear xenobiotic receptors, triggering oxidative stress, and altering the homeostasis of CYP450s in chicks. Further, it provides a theoretical basis for controlling Al exposure and highlights the importance of further studying its mechanisms to provide additional information for formulating preventive measures.

Molecular characterization of the aryl hydrocarbon receptor 2 gene in black rockfish, Sebastes schlegelii, and its expression patterns upon exposure to benzo[a]pyrene, 2,3,7,8-tetrachlorodibenzo-p-dioxin, and β-naphthoflavone

The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that mediates the toxicity of halogenated and polycyclic aromatic hydrocarbons in vertebrates. Thus, increased knowledge of AhR-mediated responses to xenobiotics is imperative. Sebastes schlegelii is increasingly being used as a model for studying environmental toxicology; hence, in this study, the presence of AhR2 was evaluated in S. schlegelii. The results showed that the predicted AhR2 amino acid sequence contained regions characteristic of other vertebrate AhRs, including the basic helix-loop-helix and PER-ARNT-SIM domains in the N-terminal half, but it had minor similarity with other vertebrate AhRs across the C-terminal half; it did not contain the distinct glutamine-rich domains found in mammalian AhR2. Phylogenetic analysis demonstrated that S. schlegelii AhR2 was clustered within the teleost AhR2 branch. Additionally, AhR2 mRNA was detectable in all 11 tissues tested, with the highest mRNA levels in the heart, pyloric ceca, and liver. Furthermore, exposure to the AhR agonists showed that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, 1 μg/g body weight) induced a significantly higher increases in AhR2 expression in the gills, liver, kidneys, and spleen in 48 h than benzo[a]pyrene (2 μg/g body weight), and β-naphthoflavone (50-μg/g body weight); AhR2 mRNA levels upon TCDD exposure were up-regulated by 16- and 10-fold in the gills and liver, respectively. These findings indicated that AhR was a highly sensitive receptor against TCDD. Thus, investigating AhR2 expression in the presence of other xenobiotics might offer further information for the elucidation of its crucial role in mediating toxicant metabolism in S. schlegelii.

Toxic effects of octocrylene on zebrafish larvae and liver cell line (ZFL)

Octocrylene (OC) is a broad-spectrum ultraviolet-absorbing chemical used in sunscreen and other personal care products. Its health effects are a concern because it has been detected in water, fish, humans, and food chains. In vivo and in vitro investigations were performed in zebrafish (Danio rerio) larvae and a zebrafish liver cell line (ZFL), respectively, to understand the potential risks and molecular mechanisms of OC toxicity. The 96-h median lethal concentration (LC₅₀) of OC was determined to be 251.8 μM in larvae and 5.5 μM in ZFL cells. Quantitative real-time PCR (qRT-PCR) showed that OC induced the expression of genes for CYPs (CYP1A, CYP3A65), estrogen receptors (ERα, ERβ1, GPER), vitellogenin (VTG1), and sex determination (BRCA2, CYP19A, DMRT1, SOX9A), both in vitro and in vivo. A whole-transcriptome sequencing method was used to evaluate the gene expression profile of larvae exposed to OC. OC was found to mediate the biosynthesis of estrogens (such as estriol) and affect the antioxidant pathway (glutathione transferases and peroxisome). These findings clarify the toxic effects and molecular mechanisms of OC and support banning its use in cosmetics.

Reproductive organ dysfunction and gene expression after orally administration of ZnO nanoparticles in murine

ZnO nanoparticles (NPs) are among the most manufactured nanoparticles in the consumer products, industries, and researches. An increasing body of evidence indicated that ZnO NPs show toxicological effects in vivo. Sex differences in the toxicity of ZnO NPs are not clear, thus the aim of this study was to investigate the effects of ZnO NPs on the female and male reproductive organs (uterus, ovary and testes). ZnO NPs were orally administered to female and male mice at dosages level of 0 and 100 mg/kg body weight. The biological material was sampled 3 days after tube feeding. The results demonstrated that Zinc contents were accumulated in the reproductive organs of treated mice. Furthermore, ZnO NPs administration induced significant decrease in the testes weight, an imbalance of hematological and serum biochemical parameters in male mice. The histopathological examinations showed that structural disorder and the appearance of cell apoptosis and death in the ZnO NPs-exposed mice. Additionally, the RT-qPCR data indicated ZnO NPs can activate mitochondrial-mediated signaling pathway and induce caspase depend damage that ultimately injured the uterus. In the ovary, ZnO NPs induce cell apoptosis in Shh pathway activated ovary cells, and affect the synthesis of steroidogenesis. In the testes, ZnO NPs effectively changed the expression level of genes related to oxidant stress, detox/metabolic process, and apoptosis. It was found that ZnO NPs caused more serious reproductive toxicity in the male mice than female mice. Overall, these findings indicated that ZnO NPs could induce exposure-related risks to reproductive health, especially in those who are at the occupational level.

Zebrafish (Danio rerio) using as model for genotoxicity and DNA repair assessments: Historical review, current status and trends

Genotoxic pollutants lead to both DNA damage and changes in cell repair mechanisms. Selecting suitable biomonitors is a fundamental step in genotoxicity studies. Thus, zebrafish have become a popular model used to assess the genotoxicity of different pollutants in recent years. They have orthologous genes with humans and hold almost all genes involved in different repair pathways. Therefore, the aim of the current study is to summarize the existing literature on zebrafish using as model system to assess the genotoxicity of different pollutants. Revised data have shown that comet assay is the main technique adopted in these studies. However, it is necessary standardizing the technique applied to zebrafish in order to enable better result interpretation and comparisons. Overall, pollutants lead to single-strand breaks (SSB), double-strand breaks (DSB), adduct formation, as well as to changes in the expression of genes involved in repair mechanisms. Although analyzing repair mechanisms is essential to better understand the genotoxic effects caused by pollutants, few studies have analyzed repair capacity. The current review reinforces the need of conducting further studies on the role played by repair pathways in zebrafish subjected to DNA damage. Revised data have shown that zebrafish are a suitable model to assess pollutant-induced genotoxicity.

Ameliorative effects of resveratrol against cadmium-induced nephrotoxicity via modulating nuclear xenobiotic receptor response and PINK1/Parkin-mediated Mitophagy

Cadmium (Cd) is a toxic pollutant with high nephrotoxicity in the agricultural environment. Resveratrol has been found to have a renoprotective effect but the underlying mechanisms of this have not yet been fully elucidated. The aim of this study is to illustrate the antagonism of resveratrol against Cd-induced nephrotoxicity. A total of 80 birds were divided randomly into 4 groups and treated via diet for 90 days as follows: control group (Con); 400 mg kg-1 resveratrol group (Resv); 140 mg kg-1 Cd group (Cd 140); and 140 mg kg-1 Cd + 400 mg kg-1 resveratrol group (Cd + Resv). It was observed that resveratrol treatment dramatically alleviated Cd-induced histopathological lesions of the kidney. Simultaneously, resveratrol mitigated Cd-induced oxidative stress by reducing MDA and H2O2 production, alleviating GSH depletion and restoring the activity of antioxidant enzymes (T-SOD, Cu-Zn SOD, CAT, GST and GSH-Px). Resveratrol activated NXRs (CAR/PXR/AHR/Nrf2) signaling pathways and exerted antidotal roles by enhancing the phase I and II detoxification systems to relieve oxidative damage. Moreover, resveratrol ameliorated Cd-induced ultrastructural abnormality and mitochondria dysfunction by recovering mitochondrial function-related factors VDAC1, Cyt C and Sirt3 upregulation and Sirt1, PGC-1α, Nrf1 and TFAM transcription restrictions. Resveratrol attenuated Cd-induced excessive mitochondrial fission and promoted mitochondrial fusion, which reversed PINK1/Parkin-mediated mitophagy initiation. Collectively, our findings explicate the potential protection against Cd-induced nephrotoxicity and mitochondria damage.

Whole-transcriptome sequencing (RNA-seq) study of the ZFL zebrafish liver cell line after acute exposure to Cd2+ ions

Cadmium (Cd) is a non-essential metal with no known biological function and a broad range of toxic effects in biological systems. We used whole-transcriptome sequencing (RNA-seq) to study the effects of Cd²⁺ toxicity in zebrafish liver cells, ZFL. The results of an RNA-Seq analysis of ZFL cells exposed to 5, 10 or 20 μM Cd²⁺ for 4- or 24-h. The differentially expressed genes affected by Cd²⁺ were analyzed by using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis to study the regulated pathways. Cd²⁺ regulated the expression of genes associated with cellular Cu, Zn, and Fe homeostasis, DNA replication leading to cell cycle arrest and apoptosis, and glutathione metabolism. Cd²⁺ boosted up the amino acid synthesis, possibly to support the glutathione metabolism for tackling the oxidative stress generated from Cd²⁺. Cd²⁺ stimulation was similar to heat or xenobiotics, based on the responses from ZFL such as endoplasmic reticulum stress and protein folding. We linked also those finding of gene activations relating to carcinogenesis of Cd. This paper provides a comprehensive analysis of the expression profiles induced by Cd²⁺ exposure in ZFL cells, as well as useful insights into the specific toxic effects.

Cadmium-induced oxidative stress promotes apoptosis and necrosis through the regulation of the miR-216a-PI3K/AKT axis in common carp lymphocytes and antagonized by selenium

Cadmium (Cd) is a primary environmental pollutant which causes the immune dysfunction of aquatic animals. MicroRNAs (miRNAs) play a key role in programmed necrosis and apoptosis of immune organs. Selenium (Se), known as an important element, can antagonize Cd toxicity in birds, but the impact of Se on common carps (Cyprinus carpio) has not been reported. To investigate the Cd-induced immunotoxicity mechanism mediated by miR-216a in splenic lymphocytes of common carp and antagonized by Se, we extracted lymphocytes from the spleen and divided them into control group, Se group (10^-6 mol/L of Na₂SeO₃), Se + Cd group and Cd group (4 × 10^-5 mol/L of CdCl₂). After 6 h of incubation, AO/EB staining, Flow cytometry, qPCR and Western blot were performed. The results showed that Cd exposure caused the apoptosis (BAX, Bcl-2, Caspase 3, Caspase 9) and programmed necrosis (RIP, RIP3, MLKL) in lymphocytes, increased the expression of CYP enzymes, glycometabolism-related enzymes and production of ROS, while irritated the oxidative stress (MDA, SOD, CAT and GSH-PX), upregulated the expression of miR-216a which attenuated the levels of PI3K. However, those variations were apparently mitigated in the Se + Cd group. In short, we have proven that Cd activates oxidative stress and miR-216a-PI3K/AKT axis disorder, thus promoting apoptosis and necrosis in lymphocytes. Moreover, Se can antagonize Cd-triggered apoptosis and necrosis in lymphocytes.

`Cadmium induced cardiac inflammation in chicken (Gallus gallus) via modulating cytochrome P450 systems and Nrf2 mediated antioxidant defense

Cadmium (Cd) has been implicated in the pathogenesis of inflammation, myocardial infarction, angiocardiopathy, even cancers. However, it is unknown that Cd-induced cardiac toxicity through Nrf2-mediate antioxidant defense and Cytochrome P450 (CYP450) system. To ascertain the chemoprevention of Cd-induced cardiac toxicity, total 60 newborn chicks were fed with different doses of Cd (0 mg/kg, 35 mg/kg and 70 mg/kg) for a period of 90 days feed administration. Results indicated Cd exposure caused cardiac histopathology changed and functions abnormal, induced NOS activities raised and cardiac inflammation, triggering inflammation factors (IL-6, IL-8, TNF-α, and NF-κb) upregulation and inhabitation of IL-10. Cd caused increase of total CYP450 and Cytochrome b5 (Cyt b5) contents, while erythromycin N-demethylase (ERND), aminopyrin N-demethylase (APND), aniline-4-hydeoxylase (AH) and NADPH-cytochrome c reductase (NCR) indicated opposite situations with different degrees of reduction in microsomes. The mRNA level of most CYP450s isoforms (CYP1A1, CYP1A2, CYP1A5, CYP1B1, CYP2C18, CYP2C45, CYP3A4, CYP3A7 and CYP3A9) were significantly increase but CYP2D6 expression level changed not obvious. Furthermore, Cd treatment caused increased the peroxidation product (MDA) and H₂O₂ over accumulation, the decreased of T-AOC accompanied by decreased activity of antioxidant enzymes (T-SOD, GST and GPX). Over accumulation of Cd lead to oxidative stress and activated Nrf2 signal pathway through upregulating pivotal target genes (HO-1, NQO1, GCLC, GCLM and SOD). These findings suggested Cd exposure caused cardiotoxicity through CYP450s enzymes homeostasis disturbance and Nrf2-mediated oxidative stress signal pathways defense. These results may provide new evidence on molecular mechanism of Cd-induced cardiac toxicity.

Acute toxic effects of polyethylene microplastic on adult zebrafish

To identify the physical effects, behavioral changes, and gene expression profiles of the phase 1 detoxification-related gene (cyp 1a) and oogenesis-related gene (vtg 1) induced by microplastics, high-density polyethylene microplastics of various sizes were used because of their dominance in coastal areas and effluent samples in Hong Kong. Adult zebrafish were used as the model organism to identify the upper and lower boundaries of microplastics ingestion and were exposed to individual polyethylene microplastics in five size ranges (10-22 μm, 45-53 μm, 90-106 μm, 212-250 μm, and 500-600 μm) at a concentration of 2 mg/L for 96 h. To study behavioral changes and targeted gene expression profiles via real-time PCR (qPCR), a mixture of microplastics in three size ranges at effluent-related (11 particles/L), moderate (110 particles/L), and high concentrations (1,100 particles/L) were applied for 96 h. The zebrafish behavior was recorded by a video camera and by two observers (interrater reliability, >85%). The results implied that the upper and lower size boundaries for microplastic ingestion were 558.4 ± 26.2 μm (yellow) and 19.7 ± 3.1 μm (red), respectively. In addition, 61 ± 10% of fish in medium concentration treatments and 61 ± 10% of fish in high concentration treatments were found with the microplastic ingestion and remaining in their intestine. In addition, 28 ± 10% of fish in high concentration treatments were found with microplastic retaining in their gills (No. of fishes = 18 in each treatment). The presence of microplastics, which occupied 89 ± 6% of intestine area, reduced the voids inside the intestine for feed. The expression of cyp1a in the intestine (medium concentration) and vtg1 in the liver (medium and high concentration) showed significant up-regulation, and abnormal behavior (i.e., seizures and tail bent downward) was observed (medium and high concentration). In summary, the effects on the aryl hydrocarbon receptor (AHR) pathway, disruption of the oogenesis process, and neurotoxicity could be caused by acute exposure of adult zebrafish to microplastics.