Generational effects of a chronic exposure to a low environmentally relevant concentration of glyphosate on rainbow trout, Oncorhynchus mykiss

Glyphosate and its formulated product Roundup Transorb R® affect locomotor activity and reproductive and developmental parameters in Jenynsia lineata fish: an intergenerational study

Glyphosate is the most extensively used herbicide globally owing to its efficacy in agricultural weed control. However, its persistence in aquatic ecosystems has raised concerns about the well-being of non-target organisms such as fish. This study aimed to evaluate the effects of chronic exposure (21 days) to glyphosate or its formulated product Roundup Transorb R®, at an environmentally relevant concentration permitted by regulations in certain countries (65 μg/L of glyphosate), on the locomotor activity and reproductive success of the fish Jenynsia lineata, as well as on the morphology/development and locomotor activity of its offspring, as intergenerational effects. Neither the pure nor formulated herbicide altered the distance traveled and velocity of adult fish exposed to the herbicide (F0), but they negatively affected reproductive success, decreasing the percentage of positive response to the presence of the female, reducing the number of gravid females, causing abortions, and lowering offspring survival (F1). In the F1 generation, a decrease in weight and length was noted along with developmental abnormalities in both treatment groups (pure or formulated glyphosate), with the formulation causing more harm. Observed developmental abnormalities included muscle atrophy, ascites, pigmentary disorders, vertebral agenesis, spinal deviation, and exophthalmia. Furthermore, parental exposure to pure glyphosate led to an increase in the distance traveled and velocity of F1 (hyperlocomotion), whereas exposure to the formulated product resulted in a decrease in these behaviors (hypolocomotion) of F1. These findings highlight the disparity in toxicity between pure glyphosate and the formulated product, underscoring the risk to the survival of fish offspring in glyphosate-contaminated environments.

In vivo estrogenicity of glyphosate, its formulations, and AMPA on transgenic zebrafish (Danio rerio) embryos

In this study, the disrupting effects of glyphosate (GLY), aminomethylphosphonic acid (AMPA), and three glyphosate-based herbicides (GBHs) on vitellogenesis in a non-concentration-dependent manner are reported for the first time in 120 h of acute exposure of zebrafish at environmentally relevant concentrations. GBHs are commonly used worldwide in weed control management. Due to their extensive application, they frequently occur in aquatic ecosystems and may affect various organisms. The active substance GLY and its major by-product, AMPA, are the most thoroughly studied chemicals; however, the adverse effects of the complex formulas of GBHs with diverse and unknown content of co-formulants are still not sufficiently researched. This study focused on the embryotoxicity, sublethal malformations, and estrogenic potency of GLY, AMPA, and four commonly used GBHs on zebrafish embryos using a wild type and an estrogen-sensitive, transgenic zebrafish line (Tg(vtg1:mCherry)). After 120 h of exposition, AMPA did not cause acute toxicity, while the LC50 of GLY was 160 mg/L. The GBHs were more toxic with LC50 values ranging from 31 to 111 GLY active equivalent (a.e.) mg/L. Exposure to 0.35-2.8 mg/L GBHs led to sublethal abnormalities: typical symptoms were structural deformation of the lower jaw and anomalies in the olfactory region. Deformity rates were 10-30% in the treated groups. In vivo, fluorescently expressed vtg1 mCherry protein in embryonic liver was detected by a non-invasive microscopic method indicating estrogenic action through vitellogenin production by GLY, AMPA, and GBHs. To confirm the in vivo findings, RT-qPCR method was performed to determine the levels of the estrogenicity-related vtg1 mRNA. After 120 h of exposure to GLY, AMPA, and three GBHs at a concentration of 0.35 mg/L, the expression of vtg1 gene was significantly up-regulated. Our results highlight the risk that short-term GLY and GBH exposure can cause developmental malformations and disrupt the hormonal balance in zebrafish embryos.

Multiomics analyses reveal dose-dependent effects of dicofol exposure on host metabolic homeostasis and the gut microbiota in mice

BACKGROUND

Environmental exposure to dicofol (DCF), one of common organochlorine pesticides (OCPs) widely used for controlling agricultural pests, elicits a potential risk for human health due to its toxicity. However, potential physiological hazards of oral DCF exposure remain largely unknown.

METHODS

Mice were exposed to relatively chronic and subacute DCF at different doses (5, 20 and 100 mg/kg) by gavage for 2 weeks. 1H NMR-based metabolomics was used to explore alterations of metabolic profiling induced by DCF exposure. Targeted metabolomics was subsequently employed to investigate the dose-dependent effects of oral DCF exposure on lipid metabolism and the gut microbiota-derived metabolites of mice. 16S rRNA gene sequencing was further employed to evaluate the changes of gut community of mice exposed to DCF.

RESULTS

Oral exposure to DCF dose-dependently induced liver injury, manifested by hepatic lipogenesis, inflammation and liver dysfunction of mice. Typically, DCF exposure disrupted host fatty acids metabolism that were confirmed by marked alteration in the levels of related genes. DCF exposure also dose-dependently caused dysbiosis of the gut bacteria and its metabolites including altered microbial composition accompanied by inhibition of bacterial fermentation.

CONCLUSION

These results provide metabolic evidence that DCF exposure dose-dependently induces liver lipidosis and disruption of the gut microbiota in mice, which enrich our views of molecular mechanism of DCF hepatoxicity.

Higher urinary glyphosate exposure is associated with increased risk of liver dysfunction in adults: An analysis of NHANES, 2013-2016

Glyphosate (GLY) exposure, both exogenous and endogenous, is a global concern. Multiple studies of model systems in vitro and in vivo have demonstrated the potential toxic effects of GLY exposure on human organs, particularly the liver and renal system. However, there is currently limited epidemiological evidence establishing a link between GLY exposure and hepatorenal function in the general population. In this study, a multivariable linear regression model and forest plots were employed to evaluate the connection between urinary GLY and biomarkers of hepatorenal function in 2241 participants from the National Health and Nutrition Examination Survey 2013-2016. Additionally, subgroup analyses were conducted based on age, gender, race, BMI, and chronic kidney disease (CKD). Alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), AST/ALT and fibrosis 4 score (FIB-4) all increased with elevated urinary GLY concentrations after adjusting for potential confounders, while albumin (ALB) exhibited the opposite trend, particularly among younger, female, non-Hispanic white, overweight, and CKD participants. Furthermore, individuals in the third tertile had a greater risk of liver dysfunction than those in the first tertile after categorizing urinary GLY concentrations. However, our study showed no proof that GLY exposure affects the ratio of urine albumin to creatinine (ACR) or serum creatinine levels. Overall, these results imply that GLY exposure may have adverse effects on human liver function.

Effect of zinc supplementation on immunotoxicity induced by subchronic oral exposure to glyphosate-based herbicide (GOBARA®) in Wistar rats

OBJECTIVES

To evaluate the effect of zinc supplementation on immunotoxicity induced by subchronic oral exposure to glyphosate-based herbicide (GBH).

METHODS

Sixty adult male Wistar rats randomly divided equally into six groups were exposed to GBH by gavage daily for 16 weeks with or without zinc pretreatment. Group DW rats received distilled water (2 mL/kg), group Z rats received zinc (50 mg/kg), and group G1 and G2 rats received 187.5 and 375 mg/kg GBH, respectively. Group ZG1 and ZG2 rats were pretreated with 50 mg/kg zinc before exposure to 187.5 and 375 mg/kg GBH, respectively. Tumor necrosis factor alpha (TNF-α) and immunoglobulin (IgG, IgM, IgE) levels were measured by enzyme-linked immunosorbent assay. Spleen, submandibular lymph node, and thymus samples were processed for histopathology.

RESULTS

Exposure to GBH (G1 and G2) significantly increased serum TNF-α concentrations and significantly decreased serum IgG and IgM concentrations compared with the control levels. Moderate-to-severe lymphocyte depletion occurred in the spleen, lymph nodes, and thymus in the GBH-exposed groups. Zinc supplementation mitigated the immunotoxic effects of GBH exposure.

CONCLUSIONS

GBH exposure increased pro-inflammatory cytokine responses, decreased immunoglobulin production, and depleted lymphocytes in lymphoid organs in rats, but zinc supplementation mitigated this immunotoxicity.

Detection and accumulation of environmentally-relevant glyphosate concentrations delivered via pulse- or continuous-delivery on passive samplers

Glyphosate is the most commonly used herbicide globally, which has contributed to its ubiquitous presence in the environment. Glyphosate application rates and delivery to surface water vary with land use. Streams in urban and agricultural catchments can experience continuous delivery of low concentrations of glyphosate and aminomethylphosphonic acid (AMPA), while their presence in forest streams occurs as an episodic pulse following silvicultural application. We assessed whether trace concentrations of glyphosate delivered as a 1-day pulse (mimic silvicultural applications) followed by flushing with deionized water would affect the detection of glyphosate or AMPA on novel passive samplers, Polar Organic Chemical Integrative Sampler with Molecular Imprinted Polymer (POCIS-MIP), compared with continuous delivery (mimic agricultural or urban applications). Within each delivery type, POCIS-MIP were exposed to seven treatment concentrations of Rodeo (equivalent to 0.0 to 1.84 μg glyphosate L-1). Experimental results demonstrate POCIS-MIP can detect differences in relative glyphosate concentrations above 0.115 μg L-1 (pulse-delivery) or 0.23 μg L-1 (continuous-delivery), but were unable to distinguish trace concentrations (i.e., < 0.115 or 0.23 μg L-1). Our results suggest POCIS-MIP may better retain glyphosate when delivered as a pulse than when delivered continuously, but both underestimated actual treatment concentrations by 46 to 56%. There is a need to demonstrate the field applicability of passive sampling methods to improve environmental monitoring of silvicultural herbicides, and our results demonstrate passive samplers were unable to distinguish lower concentrations, suggesting a limited utility for determining trace concentration levels such as those experienced during or immediately after silvicultural application.

Hematological effects of glyphosate in mice revealed by traditional toxicology and transcriptome sequencing

The herbicide glyphosate is being used worldwide. Hematological toxicity caused by glyphosate exposure has been reported, but the underlying mechanisms remain unclear. In this study, classical toxicology methods and RNA sequencing were performed to explore the molecular mechanisms related to glyphosate hematotoxicity. We found that 500 mg/kg b.w. glyphosate-based herbicide (GBH) significantly decreased leukocyte, neutrophil, lymphocyte and monocyte counts, as well as inhibited colony-forming abilities of CFU-GM, CFU-G and CFU-GEMM. RNA sequencing identified 82 and 48 differentially expressed genes (DEGs) in BM cells after treatment with 250 mg/kg and 500 mg/kg GBH, respectively. Meanwhile, GO and KEGG analyses revealed that the MAPK signaling pathway, hematopoietic cell lineage and cytokine-cytokine receptor interactions were vital pathways involved in GBH-induced toxicity in BM cells. Notably, Nr4a, Fos, Thbs1 and tnfrsf19 contributed to the hematotoxicity of GBH by regulating hematopoietic stem cell functions. In summary, our efforts enhance the understanding of the glyphosate hematotoxic responses and facilitate future studies on its corresponding mechanisms.

Long-term exposure to polyethylene microplastics and glyphosate interferes with the behavior, intestinal microbial homeostasis, and metabolites of the common carp (Cyprinus carpio L.)

Polyethylene microplastics (PE-MPs) and glyphosate (GLY) occur widely and have toxic characteristics, resulting in increased research interest. In this study, common carp were used to assess the individual and combined toxicity of PE-MPs (0, 1.5, or 4.5 mg/L) and GLY (0, 5, or 15 mg/L) on the brain-gut axis. After 60 days of exposure, the developmental toxicity, blood-brain barrier (BBB), locomotor behavior, intestinal barrier (physical barrier, chemical barrier, microbial barrier), and intestinal content metabolism of common carp were evaluated. Results showed that 15 mg/L of GLY exposure significantly reduced the mRNA expression of tight-junction genes (occludin, claudin-2, and ZO-1) in the brain, and acetylcholinesterase (AChE) activity was clearly inhibited by high concentrations of GLY. However, different concentrations of PE-MPs had no significant effect on the activity of AChE. Furthermore, the free-swimming behavior of common carp was distinctly inhibited by treatment with a combination of 15 mg/L GLY and 4.5 mg/L PE-MPs. Histological studies indicated that PE-MPs alone and in combination with GLY could disrupt the physical and chemical intestinal barriers of common carp. Additionally, the abundance and diversity of gut microbiota in common carp were significantly changed when exposed to a combination of PE-MPs and GLY. Metabolomics further revealed that PE-MPs combined with GLY triggered metabolic changes and that differential metabolites were related to amino acid and lipid metabolism. These findings illustrate that exposure to PE-MPs or GLY alone is toxic to fish and results in physiological changes to the brain-gut axis. This work offers a robust analysis to understand the mechanisms underlying GLY and MP-induced aquatic toxicity.

Metabolomic and Transcript Analysis Revealed a Sex-Specific Effect of Glyphosate in Zebrafish Liver

Glyphosate is a component of commonly used herbicides for controlling weeds in crops, gardens and municipal parks. There is increasing awareness that glyphosate-based herbicides, in addition to acting on plants, may also exert toxicity in wildlife and humans. In this study, male and female adult zebrafish were exposed to 700 µg/L of glyphosate (GLY), for 28 days. We used the metabolomic approach and UHPLC-ESI-MS to analyze liver samples to investigate the adverse effects of glyphosate on hepatic metabolism. The impact of GLY was found to be sex-specific. In female, GLY exposure affected purine metabolism by decreasing the levels of AMP, GMP and inosinic acid, consequently increasing uric acid levels with respect to the control (CTRL). Exposure to GLY also caused a decrease of UMP levels in the pyrimidine metabolism pathway. In male, GLY exposure decreased the aminoadipic acid within the lysine degradation pathway. Transcript analysis of genes involved in stress response, oxidative stress and the immune system were also performed. Results demonstrated an increased stress response in both sexes, as suggested by higher nr3c1 expression. However, the hsp70.2 transcript level was increased in female but decreased in male. The results demonstrated reduced sod1, sod2, and gpx1a in male following exposure to GLY, indicating an impaired oxidative stress response. At the same time, an increase in the cat transcript level in female was observed. mRNA levels of the pro-inflammatory interleukins litaf and cxcl8b.1 were increased in female. Taken together, the results provide evidence of disrupted nucleotide hepatic metabolism, increased stress inflammatory response in female and disruption of oxidative stress response in male.

The Influence of Herbicides to Marine Organisms Aliivibrio fischeri and Artemia salina

The aim of this work was to determine the toxic effect of the most used herbicides on marine organisms, the bacterium Aliivibrio fischeri, and the crustacean Artemia salina. The effect of these substances was evaluated using a luminescent bacterial test and an ecotoxicity test. The results showed that half maximal inhibitory concentration for A. fischeri is as follows: 15minIC50 (Roundup® Classic Pro) = 236 μg·L-1, 15minIC50 (Kaput® Premium) = 2475 μg·L-1, 15minIC50 (Banvel® 480 S) = 2637 μg·L-1, 15minIC50 (Lontrel 300) = 7596 μg·L-1, 15minIC50 (Finalsan®) = 64 μg·L-1, 15minIC50 (glyphosate) = 7934 μg·L-1, 15minIC50 (dicamba) = 15,937 μg·L-1, 15minIC50 (clopyralid) = 10,417 μg·L-1, 15minIC50 (nonanoic acid) = 16,040 μg·L-1. Median lethal concentrations for A. salina were determined as follows: LC50 (Roundup® Classic Pro) = 18 μg·L-1, LC50 (Kaput® Premium) = 19 μg·L-1, LC50 (Banvel® 480 S) = 2519 μg·L-1, LC50 (Lontrel 300) = 1796 μg·L-1, LC50 (Finalsan®) = 100 μg·L-1, LC50 (glyphosate) = 811 μg·L-1, LC50 (dicamba) = 3705 μg·L-1, LC50 (clopyralid) = 2800 μg·L-1, LC50 (nonanoic acid) = 7493 μg·L-1. These findings indicate the need to monitor the herbicides used for all environmental compartments.