Development of an alternative zebrafish model for drug-induced intestinal toxicity

Gut microbiota perturbation and subsequent oxidative stress in gut and kidney tissues of zebrafish after individual and combined exposure to inorganic arsenic and fluoride

Chronic exposure to inorganic arsenic (iAs) and fluoride (F) affect gut health and potentially damage organs. The present study investigates the interplay between gut bacteria and oxidative stress (measured by MDA level, GSH level, catalase activity, Nrf2 translocation and expression) in zebrafish exposed to F (NaF 15 ppm) and As (As2O3 50 ppb) alone or in combination. Combined exposure to As and F reduced gut bacterial alteration and imposed less oxidative stress compared to F- exposure alone. V3-V4 metagenomic sequencing revealed Pseudomonas, Aeromonas and Plesiomonas genera dominated in As or F treated groups while As+F treated group was enriched in beneficial Lactococcus and Streptococcus genera. Functional KEGG analysis demonstrated treatment-specific changes in bacterial metabolism, host organismal systems, human diseases, as well as cellular processes of microbial community were significantly affected. When Aeromonas sp. isolated from F-treated fish gut, tagged with GFP-vector and fed (~3.2 × 106 CFU/mL) to untreated fish, induced oxidative stress in gut and kidney. Gut bacteria were found to both increase and mitigate iAs or F-toxicity, whereas As+F treatment promoted a protective response. Correlation analysis between gut microbial community at genus level and oxidative stress parameters of gut and kidney, showed Aeromonas and Plesiomonas genera are strongly correlated with oxidative stress (r = 0.5-0.9, p˂0.05). This study identifies microbiome biomarkers of iAs and F toxicity on gut-kidney axis.

Exploring the potential use of Caenorhabditis elegans as an animal model for evaluating chemical-induced intestinal dysfunction

Evaluating intestinal toxicity is crucial for identifying and preventing the harmful effects of environmental chemicals. Owing to the limitations of existing models in evaluating intestinal toxicity, the development of alternative models is urgently needed. This study explored the potential use of the nematode Caenorhabditis elegans as a model animal for assessing chemical-induced intestinal dysfunction. Changes in intestinal permeability and nutrient absorption in C. elegans individuals exposed to four intestine-disrupting chemicals (sodium dodecyl sulfate (SDS), dextran sulfate sodium (DSS), lipopolysaccharide (LPS) and ethanol) were examined using dye stain assays, an enzymatic photometric assay, and fluorescent probe uptake assays. Additionally, epigallocatechin-3-gallate (EGCG), an intestine-protecting phytochemical, was chosen to prevent ethanol-induced intestinal damage. The results indicated that SDS, DSS, LPS, and ethanol compromised the intestinal barrier in C. elegans. SDS had no effect on glucose absorption, but LPS, DSS, and ethanol inhibited or tended to inhibit glucose absorption. SDS, DSS, LPS, and ethanol reduced fatty acid absorption. LPS increased peptide absorption at a low dose but decreased it at a high dose; SDS, DSS, and ethanol attenuated peptide absorption. EGCG protected against the disruption of the intestinal barrier that was induced by ethanol treatment. These results suggest that C. elegans is a suitable surrogate model animal for evaluating chemical-induced intestinal dysfunction. These findings also provide new insights into the effects of SDS, DSS, LPS, and ethanol on intestinal function and highlight the potential of EGCG as a natural dietary intervention to protect individuals who use excess alcohol from intestinal injury.

Hydroethanolic extracts from Bauhinia guianensis: a study on acute toxicity in Zebrafish embryos and adults

CONTEXT

The botanical species Bauhinia guianensis Aublet (Leguminosae-Cercidoideae) is traditionally used in the Amazon for medicinal purposes.

OBJECTIVE

The acute toxicity of the hydroethanolic extracts from B. guianensis leaves and stems (HELBg and HESBg) was evaluated in zebrafish (Danio rerio), with emphasis on the embryonic developmental stage and adult alterations.

MATERIALS AND METHODS

Extracts were analyzed on LC-DAD-MS/MS. Zebrafish eggs were inoculated individually with concentrations of HELBg and HESBg (0.25, 0.5, 0.75, 1.0, and 1.5 µg/mL), observed for 96 h. Adult zebrafish were treated with a single oral dose (100, 200, 500, 1000, and 2000 mg/kg) of HELBg and HESBg, observed for 48 h.

RESULTS

HELBg and HESBg analysis detected 55 compounds. Both extracts exhibited toxicity, including embryo coagulation at higher doses of HELBg and absence of heartbeats in embryos at all doses of HESBg. Behavioral variations were observed; tissue alterations in adult zebrafish were found at the highest doses, primarily in the liver, intestine, and kidneys because of HELBg and HESBg effects. The LD50 of HESBg was 1717 mg/kg, while HELBg exceeded the limit dose of 2000 mg/kg.

CONCLUSIONS

The study on acute toxicity of B. guianensis extracts exhibits significant toxic potential, emphasizing effects on embryonic and adult zebrafish. The results suggest relative safety of the species preparations, encouraging further clinical trials on potential biological activities.

Acute toxicology on Danio rerio embryo and adult from Chinese traditional medicine preparation Danggui Shaoyao san

ETHNOPHARMACOLOGICAL RELEVANCE

Although the Traditional Chinese Medicine (TCM) prescription of Danggui Shaoyao San (DSS) presents substantial clinical efficacy and promising clinical prospects, the safety of DSS and its extracts have been inadequately investigated. The larva-adult duality of the zebrafish model offers a more efficient approach for evaluating the safety of herbal preparations in the fields of toxicology and pharmacology.

AIM OF THE STUDY

To investigate the acute toxicity of the extract derived from Danggui Shaoyao San, a traditional Chinese medicine preparation, on both Danio rerio embryos and adult organisms.

MATERIALS AND METHODS

The components of DSS were identified using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The hatching rate of Danio rerio juveniles with different concentrations of DSS was calculated and the morphological changes of juveniles after administration were observed through a microscope. The behavioral trajectory of the adult fish was recorded by the observation tower of the automated Danio rerio analysis system, and DSS's effects on the behavior was analyzed. The pathological changes of Danio rerio gills, livers, kidneys, intestines and spermaries were examined using HE staining.

RESULTS

Compared with the control group, 25, 50 and 100 mg/L of DSS did not elicit any significant impacts on the hatching rate and morphology. Both 200 mg/L and the propylene glycol 2% reduced the hatching rate and caused the morphological teratogenic changes of the juvenile fish. The dosage of DSS below 100 mg/L had no discernible effect on the behavior of the adult fish, whereas the application of propylene glycol 2% was found to stimulate the adult fish, resulting in a notable increase in high-speed movement distance. 100 mg/L DSS group was not observed to cause any noticeable damage to the gills, livers, intestines and spermaries of Danio rerio, only mild nephrotoxicity was detected. The propylene glycol 2% group was found to result in pathological changes such as hyperplasia of epithelial cells on secondary lamellae, liver cell outline loss or atypia, tubal disorganization, goblet cell hypertrophy and irregularly arranged spermatozoa.

CONCLUSION

A viable approach for conducting toxicological studies on TCM preparations was developed and tested in this research. The findings showed that Danggui Shaoyao San has minimal acute toxicity to embryos and adult organisms at concentrations up to 100 mg/L. These results indicate that Danggui Shaoyao San is a safe TCM preparation.

Acute and Transgenerational Effects of Non-Steroidal Anti-Inflammatory Drugs on Daphnia magna

Pharmaceuticals pose a great threat to organisms inhabiting the aquatic environment. Non-steroidal anti-inflammatory drugs (NSAIDs) are major pharmaceutical pollutants with a significant presence in freshwater ecosystems. In this study, the impact of indomethacin and ibuprofen, two of the most commonly prescribed NSAIDs, was assessed on Daphnia magna. Toxicity was assessed as the immobilization of animals and used to determine non-lethal exposure concentrations. Feeding was assessed as a phenotypic endpoint and key enzymes were used as molecular endpoints of physiology. Feeding was decreased in mixture exposures for five-day-old daphnids and neonates. Furthermore, animals were exposed to NSAIDs and their mixture in chronic and transgenerational scenarios revealing changes in key enzyme activities. Alkaline and acid phosphatases, lipase, peptidase, β-galactosidase, and glutathione-S-transferase were shown to have significant changes in the first generation at the first and third week of exposure, and these were enhanced in the second generation. On the other hand, the third recovery generation did not exhibit these changes, and animals were able to recover from the induced changes and revert back to the control levels. Overall, our study points towards transgenerational exposures as more impactful laboratory studies to understand pharmaceutical stressors with a combination of molecular and phenotypic markers of physiology.

Multifunctional Graphene Oxide Nanodelivery Platform for Breast Cancer Treatment

Background

Breast cancer (BC) has the highest global prevalence among all malignancies in women and the second highest prevalence in the overall population. Paclitaxel (PTX), a tricyclic diterpenoid, is effective against BC. However, its poor solubility in water and the allergenicity of its dissolution medium limited its clinical application.

Methods

In this work, we established a multifunctional graphene oxide (GO) tumor-targeting drug delivery system using nanosized graphene oxide (nGO) modified with D-tocopherol polyethylene glycol succinate (TPGS) and arginine-glycine-aspartic acid (RGD) for PTX loading.

Results

The obtained RGD-TPGS-nGO-PTX was 310.20±19.86 nm in size; the polydispersity index (PDI) and zeta potential were 0.21±0.020 and -23.42 mV, respectively. The mean drug loading capacity of RGD-TPGS-nGO-PTX was 48.78%. RGD-TPGS-nGO-PTX showed satisfactory biocompatibility and biosafety and had no significant toxic effects on zebrafish embryos. Importantly, it exerted excellent cytotoxicity against MDA-MB-231 cells, reversed multi-drug resistance (MDR) in MCF-7/ADR cells, and showed significant anti-tumor efficacy in tumor-bearing nude mice.

Conclusion

These findings strongly suggested that the multifunctional GO tumor-targeting drug delivery system RGD-TPGS-nGO-PTX could be used in clinical settings to improve PTX delivery, reverse MDR and increase the therapeutic efficacy of BC treatment.

Progress in using zebrafish as a toxicological model for traditional Chinese medicine

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese medicine (TCM) has been applied for more than 2000 years. However, modern basic research on the safety of TCMs is limited. Establishing safety evaluation technology in line with the characteristics of TCM and conducting large-scale basic toxicity research are keys to comprehensively understand the toxicity of TCMs. In recent years, zebrafish has been used as a model organism for toxicity assessment and is increasingly utilized for toxicity research of TCMs. Yet, a comprehensive review in using zebrafish as a toxicological model for TCMs is lacked.

AIM OF THE STUDY

We aim to summarize the progress and limitation in toxicity evaluation of TCMs using zebrafish and put forward the future research ideas.

MATERIALS AND METHODS

The scientific databases, including Springer, Science Direct, Wiley, Pubmed and China Knowledge Resource Integrated (CNKI) were searched using the key words of zebrafish, toxicology, traditional Chinese medicine, acute toxicity, liver injury, cardiotoxicity, kidney toxicity, developmental toxicity, neurotoxicity, gastrointestinal irritation, immunotoxicity, ototoxicity, and osteotoxicity.

RESULTS

Zebrafish assays are low experimental cost and short cycle, easily achieving high-throughput toxicity screening, and exemption from ethical legislation up to 5 dpf. It has been widely used to evaluate the acute toxicity, liver toxicity, cardiotoxicity, nephrotoxicity, developmental toxicity, neurotoxicity, gastrointestinal irritation, immunotoxicity, and ototoxicity caused by TCMs, although some physiological difference limited its application.

CONCLUSIONS

Zebrafish is a powerful model for TCMs toxicity evaluation, but it is not flawless. The toxicity testing criterion and high throughput assays are urgent to be established. This review provides references for future studies.

Effects of MP Polyethylene Microparticles on Microbiome and Inflammatory Response of Larval Zebrafish

Plastic polymers have quickly become one of the most abundant materials on Earth due to their low production cost and high versatility. Unfortunately, some of the discarded plastic can make its way into the environment and become fragmented into smaller microscopic particles, termed secondary microplastics (MP). In addition, primary MP, purposely manufactured microscopic plastic particles, can also make their way into our environment via various routes. Owing to their size and resilience, these MP can then be easily ingested by living organisms. The effect of MP particles on living organisms is suspected to have negative implications, especially during early development. In this study, we examined the effects of polyethylene MP ingestion for four and ten days of exposure starting at 5 days post-fertilization (dpf). In particular, we examined the effects of polyethylene MP exposure on resting metabolic rate, on gene expression of several inflammatory and oxidative stress linked genes, and on microbiome composition between treatments. Overall, we found no evidence of broad metabolic disturbances or inflammatory markers in MP-exposed fish for either period of time. However, there was a significant increase in the oxidative stress mediator L-FABP that occurred at 15 dpf. Furthermore, the microbiome was disrupted by MP exposure, with evidence of an increased abundance of Bacteroidetes in MP fish, a combination frequently found in intestinal pathologies. Thus, it appears that acute polyethylene MP exposure can increase oxidative stress and dysbiosis, which may render the animal more susceptible to diseases.

Anti-foodborne enteritis effect of galantamine potentially via acetylcholine anti-inflammatory pathway in fish

Foodborne enteritis has become a limiting factor in aquaculture. Plant protein sources have already caused enteritic inflammation and inhibition in growth performance. Attempts have been made to find an effective solution to foodborne enteritis. Based on the previously suggested fish cholinergic anti-inflammatory pathway, galantamine, a typical cholinesterase inhibitor, was tested for the repression of pro-inflammatory cytokines for soybean meal induced enteritis by injection into grass carp. Both the phylogenetic analysis of cholinesterase, AchR and bioinformatic prediction, indicated galantamine's potential use as an enteritis drug. The result highlighted galantamine's potential effect for anti-enteritis in fish, especially in carps. Subsequently, a 4-week feeding trail using galantamine as an additive, in a zebrafish soybean meal induced enteritis model, demonstrated the prevention of enteritis. The results demonstrated that galantamine could prevent intestinal pathology, both histologically and molecularly, and also maintain growth performance. Reflected by gene expressional analysis, all mechanical, chemical and immune functions of the intestinal barrier could be protected by galantamine supplementation, which aided molecularly in the control of fish foodborne enteritis, through down-regulating Th17 type proinflammatory factors, meanwhile resuming the level of Treg type anti-inflammatory factors. Therefore, the current results shed light on fish intestinal acetylcholine anti-inflammation, by the dietary addition of galantamine, which could give rise to protection from foodborne enteritis.

Hydroethanolic extract from Endopleura uchi (Huber) Cuatrecasas and its marker bergenin: Toxicological and pharmacokinetic studies in silico and in vivo on zebrafish

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E. uchi stem bark hydroethanolic extract in zebrafish.

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Evaluating the in silico pharmacokinetic and toxicological parameters.

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Behavioral, biochemical and histopathological changes was dose dependent.

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In silico bergenin and its metabolites showed high intestinal absorption.

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Bergenin inhibited CYP2C9, CYP3A4 and CYP2C19.

Endopleura uchi, is used for the treatment of inflammatory disease and related to the female reproductive tract. The aim of this study was to evaluate the acute toxicity of the Endopleura uchi stem bark hydroethanolic extract (EEu) in zebrafish, emphasizing the histopathological and biochemical parameters, as well as evaluating the in silico pharmacokinetic and toxicological parameters of the phytochemical/pharmacological marker, bergenin, as their metabolites. The animals were orally treated with EEu at a single dose of 75 mg/kg, 500 mg/kg, 1000 mg/kg and 3000 mg/kg. the oral LD₅₀ of the EEu higher to the dose of 3000 mg/kg. Behavioral, biochemical and histopathological changes were dose dependent. In silico pharmacokinetic predictions for bergenin and its metabolites showed moderate absorption in high human intestinal absorption (HIA) and Caco-2 models, reduced plasma protein binding, by low brain tissue binding and no P-glycoprotein (P-Gp) inhibition. Their metabolism is defined by the CYP450 enzyme, in addition to bergenin inhibition of CYP2C9, CYP3A4 and CYP2C19. In the bergenin and its metabolites in silico toxicity test it have been shown to cause carcinogenicity and a greater involvement of the bergenin with the CYP enzymes in the I and II hepatic and renal metabolism’s phases was observed. It is possible to suggest that the histopathological damages are involved with the interaction of this major compound and its metabolites at the level of the cellular-biochemical mechanisms which involve the absorption, metabolization and excretion of these possible prodrug and drug.