The hepatoprotective effects of Salvia plebeia R. Br. extract in zebrafish (Danio rerio)

Enhanced hepatotoxicity in zebrafish due to co-exposure of microplastics and sulfamethoxazole: Insights into ROS-mediated MAPK signaling pathway regulation

The combined pollution of microplastics (MPs) and sulfamethoxazole (SMZ) often occurs in aquatic ecosystems, posing a serious threat to animal and human health. However, little is known about the liver damage caused by the single or co-exposure of MPs and SMZ, and its specific mechanisms are still poorly understood. In this study, we investigated the effects of co-exposure to 20 μm or 80 nm MPs and SMZ in both larval and adult zebrafish models. Firstly, we observed a significant decrease in the number of hepatocytes and the liver damage in larval zebrafish worsened following co-exposure to SMZ and MPs. Additionally, the number of macrophages and neutrophils decreased, while the expression of inflammatory cytokines and antioxidant enzyme activities increased after co-exposure in larval zebrafish. Transcriptome analysis revealed significant changes in gene expression in the co-exposed groups, particularly in processes related to oxidation-reduction, inflammatory response, and the MAPK signaling pathway in the liver of adult zebrafish. Co-exposure of SMZ and MPs also promoted hepatocyte apoptosis and inhibited proliferation levels, which was associated with the translocation of Nrf2 from the cytoplasm to the nucleus and an increase in protein levels of Nrf2 and NF-kB p65 in the adult zebrafish. Furthermore, our pharmacological experiments demonstrated that inhibiting ROS and blocking the MAPK signaling pathway partially rescued the liver injury induced by co-exposure both in larval and adult zebrafish. In conclusion, our findings suggest that co-exposure to SMZ and MPs induces hepatic dysfunction through the ROS-mediated MAPK signaling pathway in zebrafish. This information provides novel insights into the potential environmental risk of MPs and hazardous pollutants co-existence in aquatic ecosystems.

The Influence of Mesotrione on Human Colorectal Adenocarcinoma Cells and Possibility of Its Toxicity Mitigation by Cichoric Acid

Mesotrione, as a widely used herbicide, is present in the environment in detectable amounts, causing serious damage. Here, we aimed to investigate the effect of mesotrione on Caco-2 cells and the possibility of its toxicity mitigation by cichoric acid. Therefore, we analyzed the cytotoxicity of both these compounds and the selected oxidative stress parameters, apoptosis and interaction of both the tested compounds with the cell membrane and their accumulation within the cells. In cytotoxicity studies, the stimulating activity of mesotrione was observed, and simultaneously, the inhibitory effect of cichoric acid was noticed. This effect was related to the results of oxidative stress analysis and apoptosis measurements. The activity level of key enzymes (glutathione peroxidase, catalase and superoxide dismutase) in Caco-2 cells exposed to cichoric acid was higher as compared to that of the control. The treatment with mesotrione did not induce apoptosis in the Caco-2 cells. The penetration of the studied compounds into the Caco-2 cells was measured by using an HPLC methodology, and the results indicate mesotrione's high penetration capacity. The distribution of charge on the surface of the cell membranes changed under the influence of both compounds. Considering the mutual interactions of beneficial and potentially toxic food ingredients, it should be noted that, despite the observed favorable trend, cichoric acid is not able to overcome the toxic and cancer-stimulating effects of this pesticide.

Minocycline attenuates the bilirubin-induced developmental neurotoxicity through the regulation of innate immunity and oxidative stress in zebrafish embryos

When liver or intestinal function is impaired, bilirubin accumulates in the body and leads to neonatal jaundice. However, the potential negative effects caused by excessive accumulation of bilirubin such as developmental immunotoxicity and neurotoxicity remain unclear. We used a zebrafish model to establish bilirubin-induced jaundice symptoms and evaluated the toxic effects of bilirubin in aquatic organisms. Firstly, our results suggested that bilirubin exposure markedly decreased the survival rate, induced the developmental toxicity and increased the yellow pigment deposited in the zebrafish tail. Meanwhile, the number of macrophages and neutrophils was substantially reduced in a concentration-dependent manner. Besides, the antioxidant enzyme activities were greatly elevated while the inflammatory genes were significantly decreased after bilirubin exposure. Secondly, transcriptome analysis identified 708 genes were differentially expressed after bilirubin exposure, which animal organ morphogenesis, chemical synaptic transmission, and MAPK / mTOR signaling pathways were significantly enriched. Thirdly, bilirubin exposure leads to a significant decrease in the motility of zebrafish, including a dose-dependent decrease in the travelled distance, movement time, and average velocity. Moreover, the innate immune genes and apoptosis-related genes such as TLR4, NF-κB p65, STAT3 and p53 were elevated at a concentration of 10 μg/mL of bilirubin. Finally, our results further revealed that the anti-inflammatory and neuroprotective minocycline could partially rescue the bilirubin-induced neurobehavioral disorders in zebrafish embryos. In conclusion, our study explored the bilirubin-induced immunotoxicity and neurotoxicity in aquatic organisms, which will provide a theoretical basis for the treatment of neonatal jaundice in clinical practice.

Cannabidiol regulates the activation of hepatic stellate cells by modulating the NOX4 and NF-κB pathways

Cannabidiol (CBD) is an extract of natural cannabinoids that has therapeutic implications for a variety of ailments, such as neurological diseases, cardiomyopathy, and diabetes, due to its strong anti-inflammatory and oxidative stress properties. Our purpose was to reveal the possible underlying mechanisms and effect of CBD on the glucose oxidase (GO)-induced activation of HSC-T6 and LX-2 cells. The results showed that CBD effectively inhibited the proliferation and activation of HSC-T6 and LX-2 cells, and reduced the production of profibrotic factors to different degrees. CBD disrupted the NOX4 signalling pathway in activated HSC-T6 and LX-2 cells, reduced ROS and MDA levels, and increased SOD and GSH levels, thereby stabilizing the oxidative imbalance. CBD significantly inhibited the phosphorylation and degradation of NF-κB and IκBα, and decreased the release of TNF-α, IL-1β and IL-6. Moreover, CBD and an NF-κB-specific inhibitor (CAPE) effectively inhibited the expression of α-SMA, COL I, TNF-α and IL-1β to promote collagen metabolism and inhibit the inflammatory response. Overall, CBD inhibited HSCs activation through a and the mechanism involving the inhibition of NOX4 and NF-κB-dependent ROS regulation, thereby reducing inflammation and ameliorating oxidative imbalances.

Evaluation of the Anti-Inflammatory and Antioxidant Potential of Cymbopogon citratus Essential Oil in Zebrafish

This study explored the protective capacity of the essential oil (EO) of Cymbopogon citratus against oxidative stress induced by hydrogen peroxide (H2O2) and the inflammatory potential in zebrafish. Using five concentrations of EO (0.39, 0.78, 1.56, 3.12, and 6.25 μg/mL) in the presence of 7.5 mM H2O2, we analyzed the effects on neutrophil migration, caudal fin regeneration, cellular apoptosis, production of reactive oxygen species (ROS), and activities of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione S-transferase (GST) after 96 h of exposure. A significant decrease in neutrophil migration was observed in all EO treatments compared to the control. Higher concentrations of EO (3.12 and 6.25 μg/mL) resulted in a significant decrease in caudal fin regeneration compared to the control. SOD activity was reduced at all EO concentrations, CAT activity significantly decreased at 3.12 μg/mL, and GST activity increased at 0.78 μg/mL and 1.56 μg/mL, compared to the control group. No significant changes in ROS production were detected. A reduction in cellular apoptosis was evident at all EO concentrations, suggesting that C. citratus EO exhibits anti-inflammatory properties, influences regenerative processes, and protects against oxidative stress and apoptosis.

In Vitro and In Vivo Effects of Ulvan Polysaccharides from Ulva rigida

One of the main bioactive compounds of interest from the Ulva species is the sulfated polysaccharide ulvan, which has recently attracted attention for its anticancer properties. This study investigated the cytotoxic activity of ulvan polysaccharides obtained from Ulva rigida in the following scenarios: (i) in vitro against healthy and carcinogenic cell lines (1064sk (human fibroblasts), HACAT (immortalized human keratinocytes), U-937 (a human leukemia cell line), G-361 (a human malignant melanoma), and HCT-116 (a colon cancer cell line)) and (ii) in vivo against zebrafish embryos. Ulvan exhibited cytotoxic effects on the three human cancer cell lines tested. However, only HCT-116 demonstrated sufficient sensitivity to this ulvan to make it relevant as a potential anticancer treatment, presenting an LC₅₀ of 0.1 mg mL^-1. The in vivo assay on the zebrafish embryos showed a linear relationship between the polysaccharide concentration and growth retardation at 7.8 hpf mL mg^-1, with an LC₅₀ of about 5.2 mg mL^-1 at 48 hpf. At concentrations near the LC₅₀, toxic effects, such as pericardial edema or chorion lysis, could be found in the experimental larvae. Our in vitro study supports the potential use of polysaccharides extracted from U. rigida as candidates for treating human colon cancer. However, the in vivo assay on zebrafish indicated that the potential use of ulvan as a promising, safe compound should be limited to specific concentrations below 0.001 mg mL^-1 since it revealed side effects on the embryonic growth rate and osmolar balance.

Cyhalofop-butyl exposure induces the severe hepatotoxicity and immunotoxicity in zebrafish embryos

Cyhalofop-butyl (CyB) is a highly effective herbicide and is widely used for weed control in paddy fields. Because CyB is easily residual in the aquatic environment, its potential harm to aquatic organisms has attracted much attention and has not been fully understood. In this study, we systematically explored the hepatotoxic and immunotoxic effects of CyB exposure in zebrafish embryos. Firstly, CyB induced a decrease in the survival rate of zebrafish and led to a series of developmental abnormalities. Meanwhile, CyB can significantly reduce the size of zebrafish liver tissue and the number of hepatocytes in a dose-dependent manner. Secondly, the number of macrophages and neutrophils significantly decreased but the antioxidant enzyme activities such as CAT and MDA were greatly elevated upon CyB exposure. Thirdly, RNA-Seq analysis identified 1, 402 differentially expressed genes (DEGs) including 621 up-regulated and 781 down-regulated in zebrafish embryos after CyB exposure. KEGG and GO functional analysis revealed that the metabolic pathways of drug metabolism-cytochrome P450, biosynthesis of antibiotics, and metabolism of xenobiotics, along with oxidation-reduction process, high-density lipoprotein particle and cholesterol transport activity were significantly enriched after CyB exposure. Besides, hierarchical clustering analysis suggested that the genes involved in lipid metabolism, oxidative stress and innate immunity were largely activated in CyB-exposed zebrafish. Moreover, CyB induced zebrafish liver injury and increased hepatocyte apoptosis, which increased the protein expression levels of Bax, TLR4, NF-kB p65 and STAT3 in zebrafish. Finally, specific inhibition of TLR signaling pathway by TLR4 knock-down could significantly reduce the expression of inflammatory cytokines induced by CyB exposure. Taken together, these informations demonstrated that CyB could induce the hepatotoxicity and immunotoxicity in zebrafish embryos, and the expression levels of many genes involved in lipid metabolism and immune inflammation were obtained by RNA-Seq analysis. This study provides valuable information for future elucidating the aquatic toxicity of herbicide in aquatic ecosystems.

Therapeutic effects of Salvia balansae on metabolic disorders and testicular dysfunction mediated by a high-fat diet in Wistar rats

Medicinal plants offer an important therapeutic resource in treatment of male infertility. We aim to evaluate the possible therapeutic effects of Salvia balansae on metabolic disorders and testicular dysfunction resulting from a high-fat diet (HFD). Antioxidant activity of aqueous extract of S. balansae leaves was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, 2,2’-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assay and total antioxidant capacity (TAC) assay. Antidiabetic activity was determined by α-amylase inhibition. In vivo, HFD was administered in Wistar rats for 18 weeks and aqueous extract of S. balansae for the last 6 weeks (200 mg/Kg of body weight/day). At the term of experimentation, testosterone and some plasma parameters were analyzed and removed testes were subjected to a histomorphometric study. Our results show high levels of phenolic components in aqueous extract of S. balansae and significant antioxidant and antidiabetic activity. HFD increases body weight, causes type 2 diabetes, dyslipidemia, liver failure and inflammation. Also, HFD decreases testosterone and alters testis histological structure (seminiferous tubular degeneration, impaired spermatogenesis and interstitial fibrosis). Treatment of HFD rats with extract of S. balansae normalizes body weight and plasma parameters, increases testosterone and regenerates testicular structure and function. In summary, S. balansae could reduce metabolic complications induced by HFD and serve the basis for developing a new therapy for testicular dysfunction.

ZIF-8 nanoparticles induce neurobehavioral disorders through the regulation of ROS-mediated oxidative stress in zebrafish embryos

Zeolite imidazolate framework-8 (ZIF-8) is a nanomaterial of metal-organic frameworks (MOFs), which have various applications in drug delivery and water pollution remediation. However, little is known about its developmental neurotoxicity in aquatic organisms, especially on the low-level exposure. In the present study, we investigated the toxic effects of ZIF-8 NPs on the neuron development, behavioral traits, oxidative stress and gene expression in zebrafish embryos. Firstly, our results showed that ZIF-8 induced significantly embryonic malformations and abnormal development of nervous system in zebrafish embryos with a concentration-dependent manner. Meanwhile, the locomotor behavior was obviously inhibited while the anxiety behavior was greatly increased after ZIF-8 exposure. Secondly, the levels of ROS and antioxidant enzyme activities (CAT, SOD and MDA) together with AChE and ATPase were substantially increased in the ZIF-8 exposed groups. At the molecular level, ZIF-8 NPs could down-regulate the expression profiles of neural development-related genes (gap43, synapsin 2a and neurogenin 1) and PD-like related genes (dj-1, dynactin and parkin), but up-regulate the expression levels of neuro-inflammatory genes (nox-1, glip1a and glip1b) in larval zebrafish. In addition, we further explored the molecular mechanism of neurotoxicity induced by ZIF-8 with pharmacological experiments. The results showed that specific inhibition of ROS-mediated oxidative stress by the astaxanthin could reverse the expression patterns of ATPase, AChE and neurodevelopmental genes. Moreover, astaxanthin can partially rescue the ZIF-8-modulated locomotor behavior. Taken together, our results demonstrated that ZIF-8 had the potential to cause neurotoxicity in zebrafish embryos. These informations presented in this study will help to elucidate the molecular mechanisms of ZIF-8 nanoparticles exposure in zebrafish, which providing a scientific evaluation of its safety to aquatic ecosystems.

The toxicological effects of Eryngium foetidum extracts on zebrafish embryos and larvae depend on the type of extract, dose, and exposure time

Eryngium foetidum is a herbaceous plant found in tropical and subtropical regions. In vivo pharmacological parameters show that leaf extracts of this plant have antioxidant, anti-inflammatory, antidiabetic, and antimicrobial activities due to their bioactive compounds such as flavonoids and phenols. Despite the evidence for several bioactivities of E. foetidum, information on its safety and tolerability is limited. The objective of this study was to assess the effect and concentration of different extracts of E. foetidum on the development of zebrafish (Danio rerio) embryos. To study the impact of aqueous (AE), ethanolic (EE), and methanolic (ME) extracts, the embryos were exposed to 0.625, 1.25, 2.5, 5, and 10 mg mL-1 for up to 120-h postfertilization to assess embryonic developmental toxicity and then to 0.039, 0.078, 0.156, 0.312, and 0.625 mg mL-1 to assess the antioxidant responses of the enzymes superoxide dismutase catalase, glutathione S-transferase (GST), and cell apoptosis. The results showed that, depending on the extraction solvent, concentration used, and exposure time, E. foetidum extracts caused mortality, altered the hatching time, and promoted changes in enzymatic activities. Delays in development and increased GST activity were found in all treatments. Apoptosis was not observed in any of the treatments. In conclusion, AE, EE, and ME concentrations above 0.625 mg mL-1 can cause adverse effects on the early stages of zebrafish development.

Codium isthmocladum lectin 1 (CiL-1): Interaction with N-glycans explains antinociceptive and anti-inflammatory activities in adult zebrafish (Danio rerio)

Inflammation and oxidative stress are processes associated with different human diseases. They are treated using drugs that have several side effects. Seaweed are sources of potentially relevant natural compounds for use as treatment of these disorders. Lectins are able to reversibly interact with complex carbohydrates and modulate cell membrane glycosylated receptors through this interaction. This study aimed to determine the antinociceptive and anti-inflammatory potential of CiL-1 in adult zebrafish by modulation of TRPA1 through lectin-glycan binding. Possible neuromodulation by TRPA1 channel was also evaluated by camphor pretreatment. CiL-1 was efficacious at all tested doses, revealing anti-nociceptive and anti-inflammatory effects in adult zebrafish. This galactose-binding lectin was also able to reduce the content of ROS in brain and liver. In silico analyses showed CiL-1 interactions with both ligands tested. LacNac2 presents the most favorable binding energy with the protein. The interaction occurs at 4 subsites as an extended conformation at the site. LacNac2-Sia had a less favorable curved-shape interaction energy. Based on the predictions made for the oligosaccharides, a tetra-antenate putative glycan was schematically constructed, illustrating an interaction between TRPA1 N-glycan and CiL-1. This binding seems to be related to CiL-1 anti-inflammatory activity as result of receptor modulation.

Crocetin ameliorates non-alcoholic fatty liver disease by modulating mitochondrial dysfunction in L02 cells and zebrafish model

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese medicine considers that the etiology and pathogenesis of non-alcoholic fatty liver disease (NAFLD) are related to liver depression and qi stagnation. Saffron and its active ingredient, crocetin (CCT), are used for the treatment of metabolic diseases owing to their "Liver deobstruent" and "Liver tonic" effects. However, the effect of CCT on NAFLD has not been fully elucidated. In the present study, the effect and potential molecular mechanism of CCT were explored in both in vivo and in vitro models of NAFLD.

MATERIALS AND METHODS

CCT was isolated from saffron and purity and structure characterization were performed using HPLC, MS, ¹H-NMR, and ¹³C-NMR. The effect of CCT on the viability of L02 cells and its maximum tolerable concentration (MTC) in zebrafish were investigated. Free fatty acids (FFA) and thioacetamide (TAA) were used to induce lipid accumulation in L02 cells and steatosis in zebrafish, respectively. The effects of CCT on indexes related to lipid metabolism, oxidative stress, and mitochondrial function in NAFLD models were explored using biochemical assay kits, Western blot analysis, Reverse Transcription-Polymerase Chain Reaction (RT-PCR), histopathology analysis, and determination of mitochondrial membrane potential (ΔΨm). Morphological analysis of mitochondria was performed using transmission electron microscopy (TEM).

RESULTS

The levels of triglyceride (TG), total cholesterol (TC), malondialdehyde (MDA), and alanine/aspartate aminotransferases (ALT/AST) activities in FFA treated L02 cells were significantly reduced after CCT treatment. CCT treatment significantly increased ATP concentration, ΔΨm, and activities of superoxide dismutase (SOD), catalase (CAT), and cytochrome c oxidase (COX IV) in FFA treated L02 cells. TEM images showed restoration of mitochondrial morphology. CCT decreased ATP concentration and upregulated expression of B-cell lymphoma-2 (Bcl-2) and COX IV, whereas, CCT downregulated expression of BCL2-Associated X (Bax) and cleaved caspase-3 in TAA treated zebrafish. These findings indicated that mitochondrial dysfunction was alleviated after CCT treatment. Oil Red O staining of L02 cells and zebrafish showed that CCT treatment reversed the accumulation of lipid droplets.

CONCLUSION

In summary, CCT treatment effectively alleviated the symptoms of NAFLD and restored mitochondrial function in L02 cells and zebrafish NAFLD model.

Catechin from green tea had the potential to decrease the chlorpyrifos induced oxidative stress in larval zebrafish (Danio rerio)

Catechin is a biological compound in green tea (Camellia sinesis), which has anti-oxidant, anti-cancer, anti-apoptotic, anti-inflammatory, and attenuated effects in different experimental models. Chlorpyrifos (CPF), a broad-spectrum organophosphate insecticide, has resulted in oxidative stress, mitochondrial dysfunction, and apoptosis in zebrafish. The goal of this study is to assess whether catechin can alleviate CPF-induced oxidative damage and apoptosis in the early developmental stage of zebrafish. According to the results, we observed that 200 μg/L CPF exposure could induce oxidative stress, ROS production and changing the antioxidant-related enzymes and genes in larval zebrafish. Interestingly, catechin had the potential to reduce the oxidative damage and cell apoptosis caused by CPF exposure in larval zebrafish at different endpoints. Especially, catechin could promote the contents of GSH and activity of GST in zebrafish larvae injured by CPF, suggesting that catechin could repair oxidative damage at a certain degree by regulating the activities and gene transcription of some key enzymes related to GSH pathway in zebrafish. In addition, at transcriptional levels, a high concentration of catechin exposure reduced the expression genes of Mn-SOD, Cat, gst, and GPX induced by CPF in larval zebrafish. These genes mainly reflected the degree of oxidative damage of zebrafish, which was basically consistent with the enzyme activity. Catechin also could reduce the transcription of p53 and bax, which are tightly related to the apoptosis induced by CPF in zebrafish larvae. The expression of genes was consistent with ROS production, which proved that catechin could alleviate the apoptosis induced by CPF. This study discovered that catechin had some antioxidant effects in aquatic animals to reduce the toxicity caused by pesticides and offered the scientific basis for the utilization and development of catechin.

Authentication of the therapeutic Lamiaceae taxa by using pollen traits observed under scanning electron microscopy

Herbal medicines are gaining popularity worldwide for human healthcare because of their therapeutic potential. However, adulteration and use of unauthentic raw herbals as substitutes have become a major issue for the local communities and industry for reasons of safety and efficacy. Therefore, the authentication of medicinal plants before their use in herbal medicines is a need of time. Hence, the present study was designed with an aim, to authenticate the therapeutic Lamiaceous taxa by using pollen traits observed under scanning electron microscopy. Pollen micro-morphological studies solve the problem through discrimination and correct identification of the Lamiaceae species from the adulterants. Based on pollen features, Lamiaceae were further divided into two sub-families Lamioideae (tricolpate) and Nepetoideae (hexa-colpate). The pollen grains of Lamioideae were found as small to medium-sized, tricolpate, radially/bilateral symmetrical, sub-spheroidal and oblate shape. Besides, exine patterns bireticulate, reticulate and micro-reticulate, colpus surface sculpturing as psilate, gemmate, scabrate, and verrucate have also been reported. A significant variation was found in the pattern of the reticulum, thickness, and the number of secondary lumina per primary lumen. Similarly, Nepetoideae has a hexa zono-colpate pollen but tri and tetra zono-colpate pollen have also been observed. Hence, this study contributes to the authentication and correct identification of medicinally important Lamiaceae taxa by using scanning electron microscopic techniques and can help to solve the adulteration problem. Highlights Authentication of medicinally important Lamiceous taxa was carried out through scanning electron microscopic techniques. Chemotaxonomic characterization was used for the accurate identification of the therapeutic taxa. The medicinal, palynological and phytochemical significance of Lamiaceae taxa were evaluated. A significant variation was seen in the palynological traits that help in the determination and authentication of the therapeutic Lamiaceous species. Based on the chemotaxonomic characterization, our study can help to solve the adulteration problem for the reason of safety and efficacy.

Chlorogenic acid alleviates thioacetamide-induced toxicity and promotes liver development in zebrafish (Danio rerio) through the Wnt signaling pathway

Chlorogenic acid (CGA) is a phenylpropanoid compound that is well known to improve the antioxidant capacity and other biological activities. However, the roles of CGA in the liver development of organisms are unclear. In the present study, we aimed to investigate the function of CGA in the hepatic development in thioacetamide (TAA)-induced zebrafish embryos. We found that CGA exerted certain beneficial effects on zebrafish larvae from TAA-exposed zebrafish embryos, such as increasing the liver size, body length, heart rate, acetylcholinesterase activity, and motor ability. In addition, CGA displayed an antioxidant effect on TAA-induced zebrafish embryos by enhancing the activities of superoxide dismutase (SOD), catalase (CAT), and glucose-6-phosphate dehydrogenase (G6PDH), and decreasing of the contents of malondialdehyde (MDA), reactive oxygen species (ROS), and nitric oxide (NO). The results of western blotting analysis showed that CGA inhibited cell apoptosis by increasing the levels of Bcl2 apoptosis regulator and decreasing the levels of Bcl2 associated X (Bax), apoptosis regulator and tumor protein P53. Moreover, CGA promoted cell proliferation in TAA-induced zebrafish larvae, as detected using proliferating cell nuclear antigen fluorescence immunostaining. In addition, CGA inhibited the expression of Wnt signaling pathway genes Dkk1 (encoding Dickkopf Wnt signaling pathway inhibitors), and promoted the expression of Lef1 (encoding lymphoid enhancer binding factor 1) and Wnt2bb (encoding wingless-type MMTV integration site family, member 2Bb). When the Wnt signal inhibitor IWR-1 was added, there was no significant change in liver development in the IWR-1 + TAA group compared with the IWR-1 + TAA + CGA group (p <0.05), which suggested that CGA regulates liver development via Wnt signaling pathway. Overall, our results suggested that CGA might alleviate TAA-induced toxicity in zebrafish and promote liver development through the Wnt signaling pathway, which provides a basis for the therapeutic effect of CGA on liver dysplasia.

Toxicity of thioacetamide and protective effects of quercetin in zebrafish (Danio rerio) larvae

Quercetin is a flavonoid compound with a variety of biological properties that is widely distributed throughout the plant kingdom. Studies have found that quercetin has anti-inflammatory, antioxidant, and liver-protective effects, while thioacetamide (TAA) can cause inflammation and liver damage in zebrafish larvae. The purpose of this study was to evaluate whether quercetin can prevent TAA-induced inflammation and liver damage in zebrafish larvae and to investigate the molecular mechanisms involved. Zebrafish Tg transgenic lines were used as the experimental animals. Behavioral, oxidative stress level, proliferative antigen chromogenic antibody, and western blot analyses were carried out on zebrafish larvae in the control group and groups treated with TAA and 12 μM quercetin. The results indicated that quercetin promoted the development of zebrafish larvae damaged by TAA, exhibited antioxidant and anti-inflammatory properties, and promoted cell proliferation. Quercetin reduced the expression of p53 protein in zebrafish larvae injured by TAA, resulting in decreased levels of Bax and increased levels of Bcl-2. The findings suggested quercetin has antiapoptotic action. Quercetin reduced the expression of DKK1 and DKK2 genes related to the Wnt signaling pathway in zebrafish larvae damaged by TAA and increased the expression of Lef1 and wnt2bb. Quercetin may regulate the development of zebrafish larvae damaged by TAA through the Wnt signaling pathway. This study provides the scientific basis for the development and utilization of quercetin and the development of new related drugs.

Study of the Potential Hepatoprotective Effect of Myo-Inositol and Its Influence on Zebrafish Development

Inositol is a natural substance found widely in plants. It is used in therapies for many medical cases. The aim of this study was to determine the toxicity of myo-inositol (MI) and to investigate its potential hepatoprotective character. In the first part of the study, zebrafish embryos were incubated with 5, 10, 20, 40, 60, 80, and 100 mg/mL MI. Endpoints such as survivability, hatching rate, malformation, and mobility were evaluated. Our results demonstrated that the high doses of MI lead to increased mortality and malformations and reduce the hatching rate in comparison to the control group. Moreover, low doses of this compound do not produce a negative effect on zebrafish and even have the ability to increase the hatching rate and mobility. In the second part of the study, the hepatoprotective effect of MI was tested. Zebrafish larvae from the line Tg (fabp10a:DsRed) were incubated for 24 h with 1% and 2% ethanol (EtOH), 5 mg/mL of MI with 1% EtOH, and 5 mg/mL of MI with 2% EtOH. No significant differences between the groups with EtOH and the group treated with EtOH with MI were observed. Our results suggest that MI has no positive benefits on hepatocytes of zebrafish larvae.

Effects of sulfometuron-methyl on zebrafish at early developmental stages

Sulfometuron methyl (SM) is a widely used herbicide and thus leading to accumulation in the environment. The toxicity assessments of SM in model organisms are currently rare. In the present study, zebrafish were utilized for evaluating the detrimental effects of SM in aquatic vertebrates. Zebrafish embryos were exposed to 0, 10, 20, and 40 mg/L SM from 5.5 to 72 h post-fertilization (hpf), respectively. Consequently, SM exposure resulted in increasing the mortality rate and reducing hatching rate in larval zebrafish at 10, 20, and 40 mg/L SM-treated groups. The reduced numbers of immune cells (neutrophils and macrophages) were observed after SM exposure by a dose-dependent manner. The inflammatory responses (TLR4, MYD88, IL-1β, IL-6, IL-8, IFN-γ, IL-10, and TGF-β) were measured to estimate immune responses. Anti-inflammatory factors (IL-10 and TGF-β) were down-regulated in all the treated groups and significantly altered at 40 mg/L exposure group. Additionally, behavioral tests suggested that SM treatment significantly increased the total distance, average speed, and maximum acceleration of larval zebrafish during light-dark transition and subsequently enzymology test displayed the same trend to locomotor behaviors. The content significantly increased in oxidative stress, as reflected in ROS level in all the treated groups. The numbers of cell apoptosis were significantly increased at 20, and 40 mg/L and the highest concentration group induced the substantial increment (P < 0.001) of apoptosis-related genes including p53, Bax/Bcl-2, caspase-9, and caspase-3. In summary, our results demonstrated that exposure to SM caused toxicity of development, immune system, locomotor behavior, oxidative stress, and cell apoptosis at the early developmental stages of zebrafish.

Zebrafish and Flavonoids: Adjuvants against Obesity

Obesity is a pathological condition, defined as an excessive accumulation of fat, primarily caused by an energy imbalance. The storage of excess energy in the form of triglycerides within the adipocyte leads to lipotoxicity and promotes the phenotypic switch in the M1/M2 macrophage. These changes induce the development of a chronic state of low-grade inflammation, subsequently generating obesity-related complications, commonly known as metabolic syndromes. Over the past decade, obesity has been studied in many animal models. However, due to its competitive aspects and unique characteristics, the use of zebrafish has begun to gain traction in experimental obesity research. To counteract obesity and its related comorbidities, several natural substances have been studied. One of those natural substances reported to have substantial biological effects on obesity are flavonoids. This review summarizes the results of studies that examined the effects of flavonoids on obesity and related diseases and the emergence of zebrafish as a model of diet-induced obesity.

Effects of cyhalofop-butyl on the developmental toxicity and immunotoxicity in zebrafish (Danio rerio)

Cyhalofop-butyl is a kind of aromatic phenoxypropionic acid herbicide widely used in agriculture. However, studies on its immunotoxicity to aquatic organisms have not been reported. In this study paper, morphological, immunological, cytological, biochemical and molecular biology methods were used to study the effects of cyhalofop-butyl on the developmental toxicity and immunotoxicity in zebrafish. After cyhalofop-butyl exposed, the results showed that the zebrafish embryos had shorter length, yolk sac edema, significantly reduced number of immune cells, inflammatory response and immunocytes apoptosis. In addition, we found that the expression of immune-related genes and pro-apoptotic genes were up-regulated, and the JAK-STAT signaling pathway mediated the immunotoxicity induced by cyhalofop-butyl. Therefore, our results indicate that cyhalofop-butyl has developmental toxicity and immunotoxicity to zebrafish, and this study offer new contents for the effects of cyhalofop-butyl exposure on aquatic organisms.

Protective effects and molecular mechanisms of baicalein on thioacetamide-induced toxicity in zebrafish larvae

Baicalein is a flavonoid that is widely found in plants. Studies have shown that baicalein has anti-inflammatory, anti-cancer, and liver-protective effects. However, the effects of baicalein on TAA-induced toxicity and the underlying molecular mechanisms in zebrafish larvae are still unknown. Here, we investigated the effects of baicalein on liver development and its anti-inflammatory effects in zebrafish larvae. The results showed that baicalein has significant anti-embryonic developmental toxicity and significant antioxidant and anti-inflammatory capabilities in TAA-induced zebrafish larvae and promotes liver development and cell proliferation, reduces the expression of apoptotic proteins, and induces the expression of anti-apoptotic proteins. At the molecular level of TAA-treated zebrafish larvae, there was a decrease in the relative expression levels of mRNAs of three subfamilies, P38, ERK1, and ERK2, of the MAPK-signaling pathway and of the products of peroxisome proliferator-activated receptor (PPAR)α. Compared with TAA-treated zebrafish larvae, zebrafish larvae treated with baicalein showed an increase in the relative expression levels of P38, ERK1, and ERK2 mRNAs and the downstream products of PPARα. When MAPK signal inhibitor (SB203580) was added, it was found that liver development was inhibited and baicalin had no protective effect on TAA induced hepatotoxicity in zebrafish larvae. The results showed baicalein can protect the zebrafish larvae against toxicity induced by TAA through MAPK signal pathway. Several molecular mechanisms discovered in this study may help in the development of new drugs.