To assess hepatotoxicity and to determine the underlying mechanisms of carbamazepine (CBZ) toxicity in fish, histopathology and the liver proteome were examined after Chinese rare minnow (Gobiocypris rarus) were exposed to 1, 10, and 100 μg/L CBZ for 28 days. Histopathological changes included disruption of spatial structure, pyknotic nuclei, cellular vacuolization and deformation of cell nuclei, in addition to marked swelling of hepatocytes in all treatment groups. Protein analysis revealed that there were gender-specific responses in rare minnow following exposure, and there were 47 proteins in females and 22 proteins in males identified as differentially abundant following CBZ treatments. Pathway analysis revealed that cellular processes affected by CBZ included apoptosis, cell differentiation, cell proliferation, and the respiratory chain, indicating impaired energy homeostasis. Noteworthy was that 15 proteins identified as different in abundance were associated with carcinogenicity. Relative mRNA levels for select transcripts were consistent with the changes of proteins N-myc downstream regulated gene (NDRG), Tropomyosin 2-Beta (TPM2) and annexin A4 (ANXA4). Protein pyruvate kinase, liver and RBC (PKLR) were increased at 1 and 100 μg/L CBZ without significant difference in transcript levels. These findings characterize molecular responses and histological changes in the liver that generate new insights into CBZ hepatotoxicity in Chinese rare minnow.

Our previous study showed that the tea extract, epigallocatechin-3-gallate (EGCG), protects against microcystin-LR (MC-LR) -mediated apoptosis of human umbilical vein endothelial cells (HUVECs); however, the mechanism underlying MC-LR-induced HUVEC apoptosis remains incompletely understood. In this study, we investigated whether the nuclear factor erythroid-like 2 (NRF2)/heme oxygenase-1 (HO-1) pathway, which regulates antioxidant transcriptional regulation of oxidative stress and apoptosis, is involved in this process. Mitochondrial membrane potential (MMP) and caspase-3/-9 activities were evaluated in HUVECs by JC-1 staining and colorimetric activity assay, and a DCFH-DA fluorescent probe assay was used to quantitate reactive oxygen species (ROS) generation. The effects of MC-LR, EGCG, NF2, and HO-1 on HUVEC apoptosis were explored by western blotting and small interfering RNA (siRNA) analyses. MC-LR treatment downregulated HUVEC mitochondrial membrane potential, and decreased levels of cytochrome c release and activated caspase-3/-9, ROS generation, consequently inducing HUVEC apoptosis. EGCG treatment attenuated MC-LR-mediated HUVEC oxidative stress and mitochondria-related apoptosis. EGCG induced NRF2/HO-1 expression and activation in MC-LR treated HUVECs, while downregulation of NRF2/HO-1 by specific siRNAs revealed that NRF2/HO-1 signaling was involved in EGCG attenuation of MC-LR-induced HUVEC apoptosis. Our findings indicate that EGCG treatment protects against MC-LR-mediated HUVEC apoptosis via activation of NRF2/HO-1 signaling.

Acrylamide (AA), an environmental pollutant, has been linked to neurotoxicity, genotoxicity and carcinogenicity. AA is widely used to synthesize polymers for industrial applications, is widely found in Western-style carbohydrate-rich foods and cigarette smoke, and can also be detected in human umbilical cord blood and breast milk. This is the first study that demonstrated the cardiac developmental toxicity of AA in zebrafish embryos. Post-fertilization exposure to AA caused a clearly deficient cardiovascular system with a shrunken heart and abortive morphogenesis and function. Disordered expression of the cardiac genes, myl7, vmhc, myh6, bmp4, tbx2b and notch1b, as well as reduced number of myocardial cells and endocardial cells, indicated the collapsed development of ventricle and atrium and failed differentiation of atrioventricular canal (AVC). Although cell apoptosis was not affected, the capacity of cardiomyocyte proliferation was significantly reduced by AA exposure after fertilization. Further investigation showed that treatment with AA specifically reduced the expressions of nkx2.5, myl7 and vmhc in the anterior lateral plate mesoderm (ALPM) during the early cardiogenesis. In addition, AA exposure disturbed the restricted expressions of bmp4, tbx2b and notch1b during atrioventricular (AV) valve development and cardiac chambers maturation. Our results showed that AA-induced cardiotoxicity was related to decreased cardiac progenitor genes expression, reduced myocardium growth, abnormal cardiac chambers morphogenesis and disordered AVC differentiation. Our study demonstrates that AA exposure during a time point analogous to the first trimester in humans has a detrimental effect on early heart development in zebrafish. A high ingestion rate of AA-containing products may be an underlying risk factor for cardiogenesis in fetuses.

2,2′,4,4′-Tetrabromodiphenyl ether (BDE-47), a representative congener of polybrominated diphenyl ethers in the environment, is known to have reproductive toxicity. However, the underlying mechanisms remain to be clarified, especially in in vivo systems. In the present study, we employed Caenorhabditis elegans to study the effects of BDE-47 on reproduction. Our results showed that BDE-47 impaired worm fecundity and induced germ cell apoptosis. To elucidate the mechanisms, DNA damage and oxidative stress induction were investigated by determining the numbers of foci formation in transgenic worms expressing HUS-1::GFP and the levels of reactive oxygen species, respectively. We found that BDE-47 induced oxidative stress but not DNA damage, and treatment with the antioxidant, N-acetyl-L-cysteine, completely abrogated BDE-47-induced germ cell apoptosis. In addition, the apoptosis was blocked in mutants carrying mek-1, sek-1 or abl-1 loss-of-function alleles, but not in the p53/cep-1 deficient worms, suggesting that the mitogen-activated protein kinase (MAPK) signaling cascade was essential for BDE-47-induced germ cell apoptosis and p53/cep-1 was not required. Moreover, the apoptosis in the strains deficient for DNA damage response was not suppressed under BDE-47 treatment. Overall, we demonstrated that BDE-47 could induce oxidative stress and subsequent germ cell apoptosis in Caenorhabditis elegans through a MAPK-mediated p53-independent pathway.

Atrazine (ATR), a selective herbicide, is consistently used worldwide and has been confirmed to be harmful to the health of aquatic organisms. The release of neutrophil extracellular traps (NETs) is one of the newly discovered antimicrobial mechanisms. Although several immune functions have been analyzed under ATR exposure, the effect of ATR on NETs remains mainly unexplored. In the present study, we treated carp neutrophils using 5 μg/ml ATR and 5 μg/ml ATR combined with 100 nM rapamycin to elucidate the underlying mechanisms and to clarify the effect of ATR on phorbol myristate acetate (PMA)-induced NETs. The results of the morphological observation and quantitative analysis of extracellular DNA and myeloperoxidase (MPO) showed that NETs formation were significantly inhibited by ATR exposure. Moreover, we found that in the NETs process, ATR downregulated the expression of the anti-apoptosis gene B-cell lymphoma-2 (Bcl-2), increased the expression of the pro-apoptosis factors Bcl-2-Associated X (BAX), cysteinyl aspartate specific proteinases (Caspase3, 9), and anti-autophagy factor mammalian target of rapamycin (mTOR), decreased the expression of autophagy-related protein light chain 3B (LC3B) and glucose transport proteins (GLUT1, 4), disturbed the activities of phosphofructokinase (PFK), pyruvate kinase (PKM), and hexokinase (HK) and limited reactive oxygen species (ROS) levels, indicating that the reduced NETs release was a consequence of increased apoptosis and diminished ROS burst, autophagy and down-regulated glycolysis under ATR treatment. Meanwhile, rapamycin restored the inhibited autophagy and glycolysis and thus resisted the ATR-suppressed NETs. The present study perfects the mechanism theory of ATR immunotoxicity to fish and has a certain value for human health risk assessment.

With the growing production and applications of silica nanoparticles (SiNPs), human exposure to these nanoparticles continues to increase. However, the possible hazards that SiNP exposure may pose to human cardiovascular system and the underlying mechanisms remain unclear. In the present study, the flow cytometry was employed to investigate the potential of four sizes (10, 25, 50, 100 nm) of SiNPs to induce the apoptosis of human umbilical vein endothelial cells (HUVECs) in culture. The apoptotic pathway was also explored through the determination of the protein expression and/or activation of p53, Bcl-2, Bax, caspases-9, -7, -3, and PARP by western blot. The results showed that all the four sizes of SiNPs could significantly elicit apoptosis in HUVECs at the tested concentrations (1, 5, 25 μg/mL), compared with the negative control (p < 0.05, p < 0.01). Moreover, the apoptotic rates were increased with the elevating levels and decreasing sizes of administrative SiNPs, showing both dose- and size-dependent effect relationships. Interestingly, the enhancing phosphorylation of p53 protein (Ser15), decreasing ratio of Bcl-2/Bax protein, and elevating activation of the downstream proteins, caspase-9, -7, -3 and PARP, were also observed with the decreasing sizes of tested SiNPs, indicating that the p53-caspase pathway is the main way of the SiNP-mediated apoptosis in HUVECs and that the size is an important parameter that determines the SiNPs' potential to induce cellular response.

Di-2-ethylhexyl phthalate (DEHP) has been widely used as a plasticizer in industry. DEHP can cause testicular atrophy, yet the exact mechanism remains unclear. In this study, male mice were intragastrically (i.g.) administered with 0, 100, 200 or 400 mg DEHP/kg/day for 21 days. We found that DEHP caused disintegration of the germinal epithelium and decreased sperm density in the epididymis. Furthermore, there was a significant increase in the levels of cleaved Caspase-8, cleaved Caspase-3 and Bax proteins and a decrease in Bcl2 protein. The results indicated that DEHP could induce apoptosis of the testis tissue. Meanwhile, DEHP significantly induced autophagy in the testis tissues with increases in LC3-II, Atg5 and Beclin-1 proteins. The serum testosterone concentration decreased in the DEHP-treated group, implying that DEHP might lead to Leydig cell damage. Furthermore, oxidative stress was induced by DEHP in the testis. To further investigate the potential mechanism, mouse TM3 Leydig cells were treated with 0–80 μM DEHP for 48 h. DEHP significantly inhibited cell viability and induced cell apoptosis. Oxidative stress was involved in DEHP-induced apoptosis as N-Acetyl-L-cysteine (NAC), an inhibitor of oxidative stress, could rescue the inhibition of cell viability and induction of apoptosis by DEHP. Similar to the in vivo findings, DEHP could also induce cell autophagy. However, inhibition of autophagy by 3-Methyladenine (3-MA) significantly increased cell viability and inhibited apoptosis. Taken together, oxidative stress was involved in DEHP-induced apoptosis and autophagy of mouse TM3 Leydig cells, and autophagy might play a cytotoxic role in DEHP-induced cell apoptosis.

The multiple effect of pristine graphene (pG) toxicity on cardiovascular developmental defects was assessed using zebrafish as a model. Recently, the nanotoxicity is emerging as a critical issue, and it is more significant in embryogenesis. Especially, graphene and its derivatives have attracted a lot of interest in biomedical applications. However, very little is known about the toxic effects of pG which has been widely used carbon nanomaterial according to concentration and its effects on biological and cardiovascular development. In the present study, we examined the development of zebrafish embryos by exposing to pG (5, 10, 15, 20 and 25 μg/L) under different developmental toxicity end-points such as cardiotoxicity, cardiovascular defect, retardation of cardiac looping, apoptosis and globin expression analysis. For this, the developmental cardiotoxicity of pG at different concentrations and the specific cardiovascular defects thereof were elucidated for the first time. As a result, the exposure to pG was found to be a potential risk factor to cardiovascular system of zebrafish embryos. However, a further study on the variations of physical, molecular properties and mechanisms of nanotoxicity which vary depending on production method and surface functionalization is required. In addition, the potential risks of pG flakes to aquatic organisms and human health should be considered or checked before releasing them to the environment.

Microplastics are well-documented pollutants in the marine environment that result from production or fragmentation of larger plastic items. The knowledge about the direct effects of microplastics on immunity, including fish, is still very limited. We investigated the in vitro effects of microplastics [polyvinylchloride (PVC) and polyethylene (PE)] on gilthead seabream (Sparus aurata) and European sea bass (Dicentrarchus labrax) head-kidney leucocytes (HKLs). After 1 and 24 h of exposure of HKLs with 0 (control), 1, 10 and 100 mg mL⁻¹ MPs in a rotatory system, cell viability, innate immune parameters (phagocytic, respiratory burst and peroxidase activities) and the expression of genes related to inflammation (il1b), oxidative stress (nrf2, prdx3), metabolism of xenobiotics (cyp1a1, mta) and cell apoptosis (casp3) were studied. Microplastics failed to affect the cell viability of HKLs. In addition, they provoke very few significant effects on the main cellular innate immune activities, as decrease on phagocytosis or increase in the respiratory burst of HKLs with the highest dose of microplastics tested. Furthermore, microplastics failed to affect the expression of the selected genes on sea bass or seabream, except the nrf2 which was up-regulated in seabream HKLs incubated with the highest doses. Present results seem to suggest that continue exposure of fish to PVC or PE microplastics could impair fish immune parameters probably due to the oxidative stress produced in the fish leucocytes.

Pesticide contamination is more often found as a mixture of different pesticides in water bodies rather than individual compounds. However, regulatory risk evaluation is mostly based on the effects of individual pesticides. In the present study, we aimed to investigate the individual and joint toxicities of triazophos (TRI) and imidacloprid (IMI) to the zebrafish (Danio rerio) using acute indices and various sublethal endpoints. Results from 96-h semi-static test indicated that the LC₅₀ values of TRI to D. rerio at multiple life stages (embryonic, larval, juvenile and adult stages) ranged from 0.49 (0.36–0.71) to 4.99 (2.06–6.81) mg a.i. L⁻¹, which were higher than those of IMI ranging from 26.39 (19.04–38.01) to 128.9 (68.47–173.6) mg a.i. L⁻¹. Pesticide mixtures of TRI and IMI displayed synergistic response to zebrafish embryos. Activities of carboxylesterase (CarE) and catalase (CAT) were significantly changed in most of the individual and joint exposures of pesticides compared with the control group. The expressions of 26 genes related to oxidative stress, cellular apoptosis, immune system, hypothalamic-pituitary-thyroid and hypothalamic-pituitary-gonadal axis at the mRNA level revealed that zebrafish embryos were affected by the individual or joint pesticides, and greater changes in the expressions of six genes (Mn-sod, CXCL-CIC, Dio1, Dio2, tsh and vtg1) were observed when exposed to joint pesticides compared with their individual pesticides. Taken together, the synergistic effects indicated that it was highly important to incorporate joint toxicity studies, especially at low concentrations, when assessing the risk of pesticides.