Avermectin induces cardiac toxicity in early embryonic stage of zebrafish

Silybin prevented avermectin-induced cardiotoxicity in carp by modulating oxidative stress, inflammation, endoplasmic reticulum stress, mitochondrial apoptosis, and autophagy

Avermectin is one of the widely used anthelmintics in aquaculture and exhibits substantial toxicity to aquatic organisms. Silybin is extensively used for its anti-inflammatory, antioxidant and anti-apoptotic biological properties. Heart is essential for the survival of fish and plays a vital role in pumping blood oxygen and nutrients. Residual avermectin in water poses harm to carp. However, there is still insufficient research on whether silybin can mitigate the toxicity of avermectin to carp heart tissues. In this research, we established a model involving carp subjected to acute avermectin exposure and administered diets containing silybin to explore the potential protective effects of silybin against avermectin-induced cardiotoxicity. The results revealed that avermectin induced oxidative stress, inflammation, endoplasmic reticulum (ER) stress, mitochondrial pathway apoptosis and autophagy in the cardiac tissues of carp. Compared with the avermectin group, silybin significantly reduced ROS accumulation in cardiac tissues, restored antioxidant enzyme activity, inhibited mRNA transcript levels of pro-inflammatory-related factors, and attenuated ER stress, mitochondrial pathway apoptosis and autophagy. Protein-protein interaction (PPI) analysis demonstrated that silybin mitigated avermectin-induced cardiac oxidative stress, inflammation, ER stress, mitochondrial pathway apoptosis and autophagy. Silybin exerted anti-inflammatory effects through the Nuclear Factor kappa B (NF-κB) pathway, antioxidant effects through the Nuclear factor erythroid 2-related factor 2 (Nrf2) - Kelch-like ECH-associated protein 1 (Keap1) pathway, alleviated cardiac ER stress through the Glucose-regulated protein 78 (GRP78)/Activating Transcription Factor 6 (ATF6)/C/EBP homologous protein (CHOP) axis, suppressed apoptosis through the mitochondrial pathway, and inhibited excessive autophagy initiation through the PTEN-induced putative kinase 1 (PINK1)/Parkin RBR E3 ubiquitin protein ligase (PARKIN) signaling pathway. This study provided evidence supporting the protective effect of silybin against avermectin-induced cardiotoxicity in carp, highlighting its potential as a dietary additive to protect fish from adverse effects caused by avermectin exposure.

Ferulic acid alleviates avermectin induced renal injury in carp by inhibiting inflammation, oxidative stress and apoptosis

Avamectin (AVM), a macrolide antibiotic, is widely used in fisheries, agriculture, and animal husbandry, however, its irrational use poses a great danger to aquatic organisms. Ferulic acid (FA) is a natural chemical found in the cell walls of plants. It absorbs free radicals from the surrounding environment and acts as an antioxidant. However, the protective effect of FA against kidney injury caused by AVM has not been demonstrated. In this study, 60 carp were divided into the control group, AVM group (2.404 μg/L), FA+AVM group and FA group (400 mg/kg). Pathological examination, quantitative real-time PCR (qPCR), reactive oxygen species (ROS) and western blot were used to evaluate the preventive effect of FA on renal tissue injury after AVM exposure. Histological findings indicated that FA significantly reduced the swelling and infiltration of inflammatory cells in the kidney tissues of carp triggered by AVM. Dihydroethidium (DHE) fluorescent probe assay showed that FA inhibited the accumulation of kidney ROS. Biochemical results showed that FA significantly increased glutathione (GSH) content, total antioxidant capacity (T-AOC) and catalase (CAT) activity, and decreased intracellular malondialdehyde (MDA) content. In addition, western blot results revealed that the protein expression levels of Nrf2 and p-NF-κBp65 in the carp kidney were inhibited by AVM, but reversed by the FA. The qPCR results exhibited that FA significantly increased the mRNA levels of tgf-β1 and il-10, while significantly down-regulated the gene expression levels of tnf-α, il-6 and il-1β. These data suggest that FA can reduce oxidative stress and renal tissue inflammation induced by AVM. At the same time, FA inhibited the apoptosis of renal cells induced by AVM by decreasing the transcription level and protein expression level of Bax, and increasing the transcription level and protein expression level of Bcl2, PI3K and AKT. This study provides preliminary evidence for the theory that FA reduces the level of oxidative stress, inflammation response and kidney tissue damage caused by apoptosis in carp, providing a theoretical basis for the prevention and treatment of the AVM.

Pesticide avermectin-induced hepatotoxicity and growth inhibition in carp: Ameliorative capacity and potential mechanisms of quercetin as a dietary additive

Flavonoid quercetin (QUE) has biological activities of anti-oxidation, anti-inflammation and anti-apoptosis, however, its protective effects against avermectin (AVM) induced liver toxicity in carp remains unclear. The objective of this research is to explore the biologically potent effects of QUE in AVM-induced hepatotoxicity in carp and its underlying mechanism. Therefore, we established a liver injury model in carp induced by AVM to evaluate QUE against AVM induced liver toxicity in carp. In this investigation, AVM dosage was determined as 2.404 μg/L for both groups, and an experimentation of 30 days duration was carried out. Various methods including hematoxylin and eosin (H&E) staining, biochemical kits, real-time quantitative PCR (qRT-PCR), western blotting, TUNEL, reactive oxygen species (ROS) staining, immunofluorescence (Hoseinifar, et al.,), and oil red O staining were used in this study. Results showed that the growth inhibition of carp was relieved in the QUE treatment group comparing to the AVM group. In the QUE treatment group, there was a significant decrease in the levels of ALT and AST in carp liver tissue. Additionally, the histopathological damage and lipid accumulation were alleviated compared to the AVM group. Moreover, QUE prevented AVM induced decrease in the activities of antioxidant enzymes of superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), glutathione (GSH), catalase (CAT) and the accumulation of reactive oxygen species (ROS), but reduced accumulation of malondialdehyde (MDA). In addition, the mRNA levels of liver pro-inflammatory factors of tumor necrosis factor-α (TNF-α), interleukin-1β (iL-1β), interleukin-6 (iL-6), interleukin-10 (iL-10) and the protein levels of NOD-like receptor protein 3 (NLRP3) inflammasome were significantly down-regulated in the QUE treatment group in comparison to the AVM group. We also found that QUE could affect the expression of Bcl2-associated x (Bax), B-cell lymphoma-2 (Bcl-2), cleaved-cysteinyl aspartate specific proteinase (CCaspase3) key apoptotic proteins and TUNEL-labeled apoptotic hepatocytes by regulating SIRT1/FOXO3a signal pathway. In summary, QUE alleviated the growth inhibition, liver oxidative damage, lipid accumulation, inflammatory response, and apoptosis of carp induced by AVM. QUE is a potential protective agent against liver injury induced by AVM in carp.

Transcriptomic and proteomic fingerprints induced by the fungicides difenoconazole and metalaxyl in zebrafish embryos

In this study, we applied OMICs analysis to identify substance-specific biomarker candidates, which may act as early indicators for specific ecotoxic modes of actions (MoA). Zebrafish embryos were exposed to two sublethal concentrations of difenoconazole and metalaxyl according to a modified protocol of the OECD test guideline No. 236. At the end of exposure, total RNA and protein were extracted, followed by transcriptomics and proteomics analysis. The analysis of significantly differentially expressed genes (DEGs) and differentially expressed proteins (DEPs) revealed a positive exposure-response correlation in all test concentrations for both fungicides. Similarly, also a positive correlation between the obtained transcriptome and proteome data was observed, highlighting the robustness of our approach. From the detected DEGs, candidate biomarkers specific for difenoconazole (apoa1b, gatm, mylpfb and acta1b) and metalaxyl (lgals2b, abat, fabp1b.1 and myh9a) were selected, and their biological functions were discussed to assess the predictive potential.

Ferulic acid alleviates carp brain damage and growth inhibition caused by avermectin by modulating the Nrf2/Keap1 and NF-κB signaling pathways

The increasing concern over environmental pollution caused by the pesticide avermectin used in aquaculture has attracted significant attention. The use of avermectin, a neurotoxic pesticide, in aquatic environments leads to toxic effects on non-target organisms, particularly causing harm to fish. The phenolic compound ferulic acid possesses excellent anti-inflammatory and antioxidant capabilities. This study was conducted by establishing a chronic exposure experiment to avermectin, proposes the use of ferulic acid as a dietary additive to protect the carp brain from damage caused by exposure to avermectin. Furthermore, it investigates the anti-inflammatory and antioxidant effects of ferulic acid in the carp brain under chronic exposure to avermectin. The experimental results demonstrate that ferulic acid can alleviate brain tissue inflammation and oxidative stress by modulating the Nrf2/Keap1 and NF-κB signaling pathways. It protects the carp brain from chronic avermectin-induced damage, preserves the integrity of the carp blood-brain barrier, enhances the levels of feeding factors, and thereby alleviates carp growth inhibition. These findings provide new therapeutic strategies and a theoretical foundation for the sustainable development of carp aquaculture.

Abamectin induced brain and liver toxicity in carp: The healing potential of silybin and potential molecular mechanisms

Abamectin (ABM) abuse contaminated aquatic environment and posed a potential threat to fish health as well as public safety. Silybin (SIL), a flavonoid, has been widely used as a novel feed additive to promote fish health. This research was to explore the potential antagonistic mechanism between ABM and SIL on brain and liver toxicity was investigated in common carp. Sixty carp were divided into four groups at random: the Control group, the SIL group, the ABM group, and ABM + SIL group. This experiment lasted for 30 d. According to behavioral observation, the detection of levels of acetylcholinesterase (AchE), iron, and mRNA expression levels of blood-brain barrier (BBB) related tight junction proteins (ZO-1, Claudin7, Occludin, MMP2, MMP9, and MMP13) in brain tissues, it was found that SIL relieved neurobehavioral disorders caused by ABM-induced BBB destruction in carp. H&E staining showed SIL mitigated nerve injury and liver injury caused by ABM. Oil Red O staining and liver-related parameters showed that SIL alleviated hepatotoxicity and lipid metabolism disorder caused by ABM exposure. Furthermore, this work also explored the specific molecular mechanism of SIL in liver protection and neuroprotection. It was shown that SIL lowered ROS levels in liver and brain tissues via the GSK-3β/TSC2/TOR pathway. Simultaneously, SIL inhibited NF-κB signaling pathway and played an anti-inflammatory role. In conclusion, we believed that SIL supplementation has a protective effect on the brain and liver by regulating oxidative stress and inflammation.

Developmental toxicity of the emerging contaminant cyclophosphamide and the integrated biomarker response (IBRv2) in zebrafish

The safety of cyclophosphamide (CP) in the early developmental stages is not studied yet; it is important to study the responses at these stages because they might have relevance to CP-administered humans. We studied the developmental toxicity of CP by analysing physiological, morphological, and oxidative stress, neurotransmission enzymes, gene expression and histological endpoints in zebrafish embryos/larvae. The study lasted for 120 hpf at environmentally relevant concentrations of CP. No visible alterations were noticed in the control group. Delayed hatching, slow heart rate, yolk sac oedema, pericardial oedema, morphological deformities, the incompetence of oxidative stress biomarkers, excessive generation of ROS, apoptosis, inhibition of neurotransmitters and histopathological anomalies were observed in CP-treated groups. These alterations were found to be concentration- and duration-dependent effects for physiological and morphological endpoints, whereas concentration-dependent effects were antioxidants, ROS, apoptosis and histological endpoints. Biomarkers and gene expression were standardised using the integrated biomarker response-IBRv2 index. The IBRv2 index showed a concentration-dependent behaviour. A non-lethal developmental and teratogenic effect was observed in CP-treated zebrafish embryos/larvae at the studied concentrations. The studied biomarkers are sensitive, and the responses are interrelated; thus, their responses are useful to assess veiled and unseen hazards of pharmaceuticals.

Molecular mechanism of kidney damage caused by abamectin in carp: Oxidative stress, inflammation, mitochondrial damage, and apoptosis

Indiscriminate use of pesticides not only leads to environmental pollution problems, but also causes poisoning of non-target organisms. Abamectin (ABM), a widely used insecticide worldwide, is of wide concern due to its persistence in the environment and its high toxicity to fish. The kidney, as a key organ for detoxification, is more susceptible to the effects of ABM. Unfortunately, few studies investigated the mechanisms behind this connection. In this study, carp was used as an indicator organism for toxicological studies to investigate renal damage caused by ABM residues in carp. In this work, carp were exposed to ABM (0, 3.005, and 12.02 μg/L) for 4 d and the nephrotoxicity was assessed. Histopathological findings revealed that ABM exposure induced kidney damage in carp, as well as an increase Creatinine and BUN levels. Meanwhile, ABM as a reactive oxygen species (ROS) stimulator, boosted ROS bursts and lowered antioxidant enzyme activity while activating the body's antioxidant system, the Nrf2-Keap1 signaling pathway. The accumulation of ROS can also lead to the imbalance of the body's oxidation system, leading to oxidative stress. At the same time, NF-κB signaling pathway associated with inflammation was activated, which regulated expression levels of inflammatory cytokines (TNF-α, IL-6, IL-1β, and iNOS increased, while IL-10 and TGF-β1 decreased). In addition, ABM exposure caused structural damage to kidney mitochondria of carp, resulting in decreased mitochondrial membrane potential and ATP production capacity, and mediated apoptosis through endogenous pathways Bax/Bcl-2/Caspase-9/Caspase-3. In conclusion, ABM caused kidney damage in carp by inducing oxidative stress, inflammation, and apoptosis through mitochondrial pathway. These findings will be useful for future research into molecular mechanisms of ABM-induced nephrotoxicity in aquatic organisms.