Influence of zinc supplementation on histopathological changes in the stomach, liver, kidney, brain, pancreas and spleen during subchronic exposure of Wistar rats to glyphosate

Bioselective and Radiopaque Zinc-Biopolymeric Complex-Based Porous Biomaterials Promote Mammalian Tissue Ingrowth In Vivo While Inhibiting Microbial Biofilm Gene Expression and Biofilm Formation

Metal-organic complexes have shown astounding bioactive properties; however, they are rarely explored as biomaterials. Recent studies showed that carboxymethyl-chitosan (CMC) genipin-conjugated zinc biomimetic scaffolds have unique bioselective properties. The biomaterial was reported to be mammalian cell-friendly; at the same time, it was found to discourage microbial biofilm formation on its surface, which seemed to be a promising solution to addressing the problem of trauma-associated biofilm formation and development of antimicrobial resistance. However, the mechanically frail characteristics and zinc overload raise concerns and limit the potential of the said biomaterials. Hence, the present work is focused on improving the strength of the earlier scaffold formulations, testing its in vivo efficacy and reaffirming its action against biofilm-forming microbe Staphylococcus aureus. Scaling up of CMC proportion increased rigidity, and 8% CMC was found to be the ideal concentration for robust scaffold fabrication. Freeze-dried CMC scaffolds with or without genipin (GP) cross-linking were conjugated with zinc using 2 M zinc acetate solution. Characterization results indicated that the CMC-Zn scaffolds, without genipin, showed mechanical properties close to bone fillers, resist in vitro enzymatic degradation until 4 weeks, are porous in nature, and have radiopacity close to mandibular bones. Upon implantation in a subcutaneous pocket of Wistar rats, the scaffolds showed tissue in-growth with simultaneous degradation without any signs of toxicity past 28 days. Neither were there any signs of toxicity in any of the vital organs. Considering many superior properties among the other formulations, the CMC-Zn scaffolds were furthered for biofilm studies. CMC-Zn showed negligible S. aureus biofilm formation on its surface as revealed by an alamar blue-based study. RT-PCR analysis revealed that CMC-Zn downregulated the expression of pro-biofilm effector genes such as icaC and clfB. A protein docking study predicted the inhibitory mechanism of CMC-Zn. Although it binds strongly when alone, at high density, it may cause inactivation of the transmembrane upstream activators of the said genes, thereby preventing their dimerization and subsequent inactivation of the effector genes. In conclusion, zinc-conjugated carboxymethyl-chitosan scaffolds are mechanically robust, porous, yet biodegradable, harmless to the host in the long term, they are radiopaque and prevent biofilm gene expression in notorious microbes; hence, they could be a suitable candidate for bone filler applications.

The effects of a glyphosate-based herbicide on the bovine gametes during an in vitro embryo production model

Roundup® (R), while it is the most used herbicide globally, and its residues are ubiquitous in urban and suburban areas, its impact on vertebrates' safety remains highly debated. Here, in three in vitro experiments, we investigated the effects of a very low dose (1 ppm) of R on the fertilization capacity and embryo development in cattle. In the first experiment, frozen-thawed bull semen exposed to R for 1 h exhibited reduced motility parameters but unaffected fertilization ability. However, after in vitro fertilization, the rates of embryo formation were significantly lower compared to the untreated controls. In the second experiment, oocytes exposed to R during in vitro maturation showed reduced cleavage rates, and the embryo yield on days 7, 8, and 9 of embryo culture was significantly lower than that of the controls. In the third experiment, oocytes were matured in the presence of R and in a medium containing both R and Zinc, chosen to offer antioxidant protection to the oocytes. Day-7 blastocysts were analyzed for the expression of genes associated with oxidative stress, apoptosis, and epigenetic reprogramming. Exposure to R markedly suppressed embryo formation rates compared to the controls. The combination of R with Zinc restored the blastocyst yield, which on days 8 and 9 was comparable to that of the controls and higher than the groups exposed only to R on all days. The gene expression analysis revealed that R promotes oxidative stress development, triggers apoptosis, and induces epigenetic changes in developing embryos, while zinc presence alleviates these adverse effects of R. These findings imply that even at very low doses, R could be highly toxic, leading to functional abnormalities in both gametes, potentially affecting fertility in both genders.

Glyphosate-induced changes in the expression of galanin and GALR1, GALR2 and GALR3 receptors in the porcine small intestine wall

Glyphosate is the active ingredient of glyphosate-based herbicides and the most commonly used pesticide in the world. The goal of the present study was to verify whether low doses of glyphosate (equivalent to the environmental exposure) evoke changes in galanin expression in intramural neurons in the small intestine in pigs and to quantitatively determine changes in the level of galanin receptor encoding mRNA (GALR1, GALR2, GALR3) in the small intestine wall. The experiment was conducted on 15 sexually immature gilts divided into three study groups: control (C)-animals receiving empty gelatin capsules; experimental 1 (G1)-animals receiving a low dose of glyphosate (0.05 mg/kg b.w./day); experimental 2 (G2)-animals receiving a higher dose of glyphosate (0.5 mg/kg b.w./day) orally in gelatine capsules for 28 days. Glyphosate ingestion led to an increase in the number of GAL-like immunoreactive intramural neurons in the porcine small intestine. The results of RT-PCR showed a significant increase in the expression of mRNA, which encodes the GAL-receptors in the ileum, a decreased expression in the duodenum and no significant changes in the jejunum. Additionally, intoxication with glyphosate increased the expression of SOD2-encoding mRNA in the duodenum and decreased it in the jejunum and ileum, but it did not affect SOD1 expression. The results suggest that it may be a consequence of the cytotoxic and/or neurotoxic properties of glyphosate and/or its ability to induce oxidative stress.

Effects of glyphosate, mancozeb and their combinations on mouse neuroblastoma cells

Pesticides-related toxicities have long been studied. Data regarding the effects of combined exposure to environmentally relevant pesticides however remain lacking. The herbicide glyphosate and the fungicide mancozeb are extensively used in agriculture. Residues of both compounds are frequently found in food and water and therefore, environmental exposure to both pesticides is a possibility. Neurotoxicity of glyphosate, mancozeb and their combinations were investigated using mouse neuroblastoma cells. Cytotoxicity observed with the glyphosate and mancozeb combinations was higher than that observed when glyphosate was tested alone. Combinations of glyphosate followed by mancozeb increased copper, manganese, and zinc levels. Mixture of mancozeb + glyphosate increased manganese and zinc levels. Combination of mancozeb followed by glyphosate increased copper and zinc levels. Glutathione ratio was decreased as a result of combinations of glyphosate and mancozeb. The decrease in glutathione ratio was greater in the combination groups than in glyphosate alone.

Maternal impacts of pre-conceptional glyphosate exposure

Maternal glyphosate (GLY) impacts remain unclear despite associations between urinary GLY and birth outcomes. Whether maternal pre-conceptional GLY exposure would have phenotypic and molecular impacts in the dam and offspring was tested. Female C57BL6 mice (6 wk) were exposed to saline (CT; n = 20) or GLY (2 mg/kg; n = 20) per os five d per week for 20 wk. Females were housed with males and on gestation day (GD) 14, divided into: CT non-pregnant (CNP), CT pregnant (CP), GLY non-pregnant (GNP), GLY pregnant (GP). Another cohort (CT; n = 10 or GLY; n = 10) completed three pregnancy rounds and pregnancy index (PI), number of pups per litter and pups surviving to postnatal day (PND) 5 calculated. The PI in GLY mice was higher in breeding rounds 1 and 2, but lower in round 3. Pregnancy increased (P ≤ 0.1) GD14 liver and ovary weight. Spleen weight was increased (P < 0.05) in GP relative to GNP mice. No offspring phenotypic impacts were observed. Approximately six months after cessation of exposure, secondary follicle number was reduced (P < 0.05) by pre-conceptional GLY exposure. The ovarian proteome analyzed by LC-MS/MS was altered (P < 0.05) by pregnancy (49 increased, 43 decreased) and GLY exposure (non-pregnant: 75 increased, 22 decreased, pregnant: 27 increased, 29 decreased; aged dams: 60 increased, 98 decreased) with several histone proteins being altered. These findings support ovarian transient and persistent impacts of GLY exposure and identify pathways as potential modes of action.

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.

Evaluation of the developmental effects of a glyphosate-based herbicide complexed with copper, zinc, and manganese metals in zebrafish

The use of glyphosate-based herbicides (GBH) has increased dramatically, being currently the most used herbicides worldwide. Glyphosate acts as a chelating agent, capable of chelate metals. The synergistic effects of metals and agrochemicals may pose an environmental problem as they have been shown to induce neurological abnormalities and behavioural changes in aquatic species. However, as their ecotoxicity effects are poorly understood, evaluating the impacts of GBH complexed with metals is an ecological priority. The main objective of the study was to evaluate the potentially toxic effects caused by exposure to a GBH (1 μg a.i. mL^-1), alone or complexed with metals (Copper, Manganese, and Zinc (100 μg L^-1)), at environmentally relevant concentrations, during the early period of zebrafish (Danio rerio) embryo development (96 h post-fertilization), a promising model for in vivo developmental studies. To clarify the mechanisms of toxicity involved, lethal and sublethal development endpoints were assessed. At the end of the exposure, biochemical and cell death parameters were evaluated and, 24 h later, different behavioural responses were assessed. The results showed that metals induced higher levels of toxicity. Copper caused high mortality, low hatching, malformations, and changes in biochemical parameters, such as decreased Catalase (CAT) activity, increased Glutathione Peroxidase (GPx), Glutathione S-Transferase (GST), reduced Glutathione (GSH) and decreased Acetylcholinesterase (AChE) activity, also inducing apoptosis and changes in larval behaviour. Manganese increased the activity of SODs enzymes. Zinc increased mortality, reactive oxygen species (ROS) levels, superoxide dismutase activity (SODs) and caused a decrease in AChE activity. Embryos/larvae exposed to the combination of GBH/Metal also showed teratogenic effects during their development but in smaller proportions than the metal alone. Although more studies are needed, the results suggest that GBH may interfere with the mechanisms of metal toxicity at the biochemical, physiological, and behavioural levels of zebrafish.

Safety and Immunogenicity Analysis of a Newcastle Disease Virus (NDV-HXP-S) Expressing the Spike Protein of SARS-CoV-2 in Sprague Dawley Rats

Despite global vaccination efforts, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to evolve and spread globally. Relatively high vaccination rates have been achieved in most regions of the United States and several countries worldwide. However, access to vaccines in low- and mid-income countries (LMICs) is still suboptimal. Second generation vaccines that are universally affordable and induce systemic and mucosal immunity are needed. Here we performed an extended safety and immunogenicity analysis of a second-generation SARS-CoV-2 vaccine consisting of a live Newcastle disease virus vector expressing a pre-fusion stabilized version of the spike protein (NDV-HXP-S) administered intranasally (IN), intramuscularly (IM), or IN followed by IM in Sprague Dawley rats. Local reactogenicity, systemic toxicity, and post-mortem histopathology were assessed after the vaccine administration, with no indication of severe local or systemic reactions. Immunogenicity studies showed that the three vaccination regimens tested elicited high antibody titers against the wild type SARS-CoV-2 spike protein and the NDV vector. Moreover, high antibody titers were induced against the spike of B.1.1.7 (alpha), B.1.351 (beta) and B.1.617.2 (delta) variants of concern (VOCs). Importantly, robust levels of serum antibodies with neutralizing activity against the authentic SARS-CoV-2 USA-WA1/2020 isolate were detected after the boost. Overall, our study expands the pre-clinical safety and immunogenicity characterization of NDV-HXP-S and reinforces previous findings in other animal models about its high immunogenicity. Clinical testing of this vaccination approach is ongoing in different countries including Thailand, Vietnam, Brazil and Mexico.

Ameliorative effect of N-acetylcysteine against glyphosate-induced hepatotoxicity in adult male albino rats: histopathological, biochemical, and molecular studies

Glyphosate (GLP) is the most commonly used herbicide that presents many hazards to the environment and living organisms. The present study aimed to explore hepatotoxic properties of GLP on adult albino rats, and the ability of N-acetylcysteine (NAC) to ameliorate these toxic effects. Thirty mature male albino rats were distributed into 3 groups (10 rats/group): Group I (C) a negative control, Group II (GLP) orally administered Roundup 0.8503 ml/kg/day which contain GLP (375 mg/kg) (1/10 of LD50) by gavage needle, and Group III (NAC+ GLP) received NAC (160 mg/kg, 1h before Roundup) by gavage needle and Roundup (0.8503 ml/kg) orally for 6 weeks. Blood and liver samples were collected and processed for biochemical, histopathological, ultrastructural, and immunohistochemical investigations. Group II displayed a significant elevation of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and malondialdehyde (MDA) levels, as well as overexpression of apoptotic markers. The total antioxidant capacity "TAC" and mRNA expression of NRF2 were significantly decreased. Concerning the histopathological findings, there were various degenerative changes as the hepatocytes showed hydropic swelling with nuclear pyknosis. These alterations were confirmed ultrastructurally as most of the cytoplasmic organelles were lost and the mitochondria appeared to deteriorate. Immunohistochemical results showed intense immunoreactivity against proliferating cell nuclear antigen (PCNA) and caspase-3. NAC administration before GLP partially ameliorates these alterations. ALT, AST, and MDA levels as well as expression of apoptotic markers were significantly reduced. TAC and mRNA expression of NRF2 were significantly increased. Histopathological alterations were partially improved as the hepatocytes returned normal and ultrastructurally they showed nearly normal cytoplasmic organelles. Additionally, the intense expression of PCNA and caspase-3 was significantly reduced. We concluded that NAC can ameliorate most of the adverse effects of GLP exposure through its antioxidant property and free radicals scavenging capacity.

Relationship between heavy metal accumulation and histological alterations in voles from alpine and forest habitats of the West Carpathians

The interaction between toxic heavy metals and bio-elements in internal organs and femoral bones and their potential impacts on bone structural properties and renal histopathological changes in bank voles and snow voles were investigated. Our results reveal that heavy metals Hg and Pb accumulate more in femoral bones of alpine habitats than forests. In snow voles, the parameters of the primary osteons' vascular canals (length, average perimeter and area) simultaneously decreased with an increase of Pb and Sr. Wider primary osteons' vascular canals of snow voles contained decreased levels of K, but increased Ba. In bank voles, the number of primary osteons increased in alpine habitats along with K, Hg, and Pb accumulation. In the kidneys of bank voles, rising levels of Rb, Hg, and Zn were detected in alpine habitats. Hg increases the most in kidney tissue from alpine habitats in both vole species, and Hg levels (mean value 0.25 μg/g, max. value 0.55 μg/g) in the renal tissues of bank voles from alpine localities are similar to Hg levels from Hg-polluted industrial areas in other studies. This reflects that alpine areas of the Tatra Mountains are highly contaminated with Hg. The intensity of renal hemosiderosis relates significantly to Zn, Fe, and Cu levels in snow voles, with Fe and Zn levels in bank voles from forest habitats, and with Rb in bank voles from alpine habitats. The intensity of tubule necrosis in renal tissues of bank voles from alpine habitats was negatively related to Se content. In bank voles from forest habitats, significant positive correlations were found between the intensity of glomerular hyperplasia and amounts of Zn. The interactions of the detected element's association with bone tissue and internal organs are discussed.

Controversies over human health and ecological impacts of glyphosate: Is it to be banned in modern agriculture?

Glyphosate, introduced by Monsanto Company under the commercial name Roundup in 1974, became the extensively used herbicide worldwide in the last few decades. Glyphosate has excellent properties of fast sorption in soil, biodegradation and less toxicity to nontarget organisms. However, glyphosate has been reported to increase the risk of cancer, endocrine-disruption, celiac disease, autism, effect on erythrocytes, leaky-gut syndrome, etc. The reclassification of glyphosate in 2015 as 'probably carcinogenic' under Group 2A by the International Agency for Research on Cancer has been broadly circulated by anti-chemical and environmental advocacy groups claiming for restricted use or ban of glyphosate. In contrast, some comprehensive epidemiological studies involving farmers with long-time exposure to glyphosate in USA and elsewhere coupled with available toxicological data showed no correlation with any kind of carcinogenic or genotoxic threat to humans. Moreover, several investigations confirmed that the surfactant, polyethoxylated tallow amine (POEA), contained in the formulations of glyphosate like Roundup, is responsible for the established adverse impacts on human and ecological health. Subsequent to the evolution of genetically modified glyphosate-resistant crops and the extensive use of glyphosate over the last 45 years, about 38 weed species developed resistance to this herbicide. Consequently, its use in the recent years has been either restricted or banned in 20 countries. This critical review on glyphosate provides an overview of its behaviour, fate, detrimental impacts on ecological and human health, and the development of resistance in weeds and pathogens. Thus, the ultimate objective is to help the authorities and agencies concerned in resolving the existing controversies and in providing the necessary regulations for safer use of the herbicide. In our opinion, glyphosate can be judiciously used in agriculture with the inclusion of safer surfactants in commercial formulations sine POEA, which is toxic by itself is likely to increase the toxicity of glyphosate.

Effect of zinc supplementation on chronic hepatorenal toxicity following oral exposure to glyphosate-based herbicide (Bushfire®) in rats

OBJECTIVES

To assess the effects of zinc pretreatment on hepatorenal toxicity following chronic exposure to glyphosate-based herbicides in male rats.

METHODS

Following zinc pretreatment (50 mg/kg and 100 mg/kg), 14.4 to 750 mg/kg of oral glyphosate (Bushfire® herbicide) was administered daily for 36 weeks. Thereafter, serum samples were obtained following jugular venipuncture. Liver and kidney samples were processed for histopathological examination.

RESULTS

Serum aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase activity as well as levels of bicarbonate, calcium, creatinine were significantly increased following chronic exposure to Bushfire®. Serum levels of sodium, potassium, chloride, total protein, albumin, globulin and urea were unchanged. Moderate to severe coagulative necrosis of hepatocytes as well as glomerular and renal tubular necrosis were observed in herbicide-treated rats. Zinc pretreatment reduced the elevation of serum enzymes associated with hepatobiliary lesions, abrogated hypercalcemia and metabolic alkalosis, and mitigated serum accumulation of creatinine following Bushfire® exposure, but was ineffective in completely preventing histological lesions.

CONCLUSION

Chronic Bushfire® exposure in rats caused hepatorenal toxicity. The effects of exposure on serum parameters were ameliorated by zinc pretreatment, but the histopathological changes associated with toxicity persisted in milder forms in zinc-pretreated animals.

Oxidative stress and mitochondrial dysfunction in organophosphate pesticide-induced neurotoxicity and its amelioration: a review

Organophosphorus pesticides (OPs) are widely used for controlling pests worldwide. The inhibitory effects of these pesticides on acetylcholinesterase lead to neurotoxic damages. The oxidative stress is responsible for several neurological diseases, including Parkinson's disease, seizure, depression, and Alzheimer's disease. Strong evidence suggests that dysfunction of mitochondria and oxidative stress are involved in neurological diseases. OPs can disturb the function of mitochondria by inducing oxidative stress. In the present study, we tried to highlight the role of dysfunction of mitochondria and the induction of oxidative stress in the neurotoxicity induced by OPs. Additionally, the amelioration of OP-induced oxidative damage and mitochondrial dysfunctional through the chemical and natural antioxidants have been discussed.

Glyphosate Induces Metaphase II Oocyte Deterioration and Embryo Damage by Zinc Depletion and Overproduction of Reactive Oxygen Species

Glyphosate is the most popular herbicide used in modern agriculture, and its use has been increasing substantially since its introduction. Accordingly, glyphosate exposure from food and water, the environment, and accidental and occupational venues has also increased. Recent studies have demonstrated a relationship between glyphosate exposure and a number of disorders such as cancer, immune and metabolic disorders, endocrine disruption, imbalance of intestinal flora, cardiovascular disease, and infertility; these results have given glyphosate a considerable amount of media and scientific attention. Notably, glyphosate is a powerful metal chelator, which could help explain some of its effects. Recently, our findings on 2,3-dimercapto-1-propanesulfonic acid, another metal chelator, showed deterioration of oocyte quality. Here, to generalize, we investigated the effects of glyphosate (0 - 300 μM) on metaphase II mouse oocyte quality and embryo damage to obtain insight on its mechanisms of cellular action and the tolerance of oocytes and embryos towards this chemical. Our work shows for the first time that glyphosate exposure impairs metaphase II mouse oocyte quality via two mechanisms: 1) disruption of the microtubule organizing center and chromosomes such as anomalous pericentrin formation, spindle fiber destruction and disappearance, and defective chromosomal alignment and 2) substantial depletion of intracellular zinc bioavailability and enhancement of reactive oxygen species accumulation. Similar effects were found in embryos. These results may help clarify the effects of glyphosate exposure on female fertility and provide counseling and preventative steps for excessive glyphosate intake and resulting oxidative stress and reduced zinc bioavailability.

Glyphosate-based herbicide impairs energy metabolism and increases autophagy in C6 astroglioma cell line

Several investigators demonstrated that glyphosate formulations produce neurotoxicity associated with oxidative stress, alterations in glutamatergic system, inhibition of acetylcholinesterase activity and mitochondrial dysfunction. However, the underlying molecular mechanisms following exposure to this herbicide on astrocytes are unclear. Thus, the aim of the present study was to determine the activity of enzymes related to energy metabolism, in addition to oxidative stress parameters, mitochondrial mass, nuclear area, and autophagy in astrocytes treated with a glyphosate-based herbicide. Our results showed that 24 h exposure to a glyphosate-based herbicide decreased (1) cell viability, (2) activities of mitochondrial respiratory chain enzymes and creatine kinase (CK), (3) mitochondrial mass, and (4) nuclear area in rat astroglioma cell line (C6 cells). However, non-protein thiol (NPSH) levels were increased but catalase activity was not changed in cells exposed to the herbicide at non-cytotoxic concentrations. Low glyphosate concentrations elevated content of cells positive to autophagy-related proteins. Nuclear factor erythroid 2-related factor (Nrf2), NAD(P)H dehydrogenase [quinone] 1 (NQO1) and PTEN-induced kinase 1 (PINK1) labeling were not markedly altered in cells exposed to glyphosate at the same concentrations that an increase in NPSH levels and positive cells to autophagy were found. It is conceivable that mitochondria and CK may be glyphosate-based herbicides targets. Further, autophagy induction and NPSH increase may be mechanisms initiated to avoid oxidative stress and cell death. However, more studies are needed to clarify the role of autophagy in astrocytes exposed to the herbicide and which components of the formulation might be triggering the effects observed here.

A comprehensive analysis of the animal carcinogenicity data for glyphosate from chronic exposure rodent carcinogenicity studies

Since the introduction of glyphosate-tolerant genetically-modified plants, the global use of glyphosate has increased dramatically making it the most widely used pesticide on the planet. There is considerable controversy concerning the carcinogenicity of glyphosate with scientists and regulatory authorities involved in the review of glyphosate having markedly different opinions. One key aspect of these opinions is the degree to which glyphosate causes cancer in laboratory animals after lifetime exposure. In this review, twenty-one chronic exposure animal carcinogenicity studies of glyphosate are identified from regulatory documents and reviews; 13 studies are of sufficient quality and detail to be reanalyzed in this review using trend tests, historical control tests and pooled analyses. The analyses identify 37 significant tumor findings in these studies and demonstrate consistency across studies in the same sex/species/strain for many of these tumors. Considering analyses of the individual studies, the consistency of the data across studies, the pooled analyses, the historical control data, non-neoplastic lesions, mechanistic evidence and the associated scientific literature, the tumor increases seen in this review are categorized as to the strength of the evidence that glyphosate causes these cancers. The strongest evidence shows that glyphosate causes hemangiosarcomas, kidney tumors and malignant lymphomas in male CD-1 mice, hemangiomas and malignant lymphomas in female CD-1 mice, hemangiomas in female Swiss albino mice, kidney adenomas, liver adenomas, skin keratoacanthomas and skin basal cell tumors in male Sprague-Dawley rats, adrenal cortical carcinomas in female Sprague-Dawley rats and hepatocellular adenomas and skin keratocanthomas in male Wistar rats.

Genotoxic, cytotoxic, and cytopathological effects in rats exposed for 18 months to a mixture of 13 chemicals in doses below NOAEL levels

The present study investigates the genotoxic and cytotoxic effects of long term exposure to low doses of a mixture consisting of methomyl, triadimefon, dimethoate, glyphosate, carbaryl, methyl parathion, aspartame, sodium benzoate, EDTA, ethylparaben, buthylparaben, bisphenol A and acacia gum in rats. Four groups of ten Sprangue Dawley rats (5 males and 5 females per group) were exposed for 18 months to the mixture in doses of 0xNOAEL, 0.0025xNOAEL, 0.01xNOAEL and 0.05xNOAEL (mg/kg bw/day). After 18 months of exposure, the rats were sacrificed and their organs were harvested. Micronuclei frequency was evaluated in bone marrow erythrocytes whereas the organs were cytopathologically examined by the touch preparation technique. The exposure to the mixture caused a genotoxic effect identified only in females. Cytopathological examination showed specific alterations of tissue organization in a tissue-type dependent manner. The observed effects were dose-dependent and correlated to various tissue parameters. Specifically, testes samples revealed degenerative and cellularity disorders, liver hepatocytes exhibited decreased glycogen deposition whereas degenerative changes were present in gastric cells. Lung tissue presented increased inflammatory cells infiltration and alveolar macrophages with enhanced phagocytic activity, whereas brain tissue exhibited changes in glial and astrocyte cells' numbers. In conclusion, exposure to very low doses of the tested mixture for 18 months induces genotoxic effects as well as monotonic cytotoxic effects in a tissue-dependent manner.

Antioxidant and cytoprotective effects of N-acetylcysteine against subchronic oral glyphosate-based herbicide-induced oxidative stress in rats

It is claimed that oxidative stress has a prominent role in the mechanism of toxic effects formed by glyphosate-based herbicide (GBH) in living systems. A strong thiol compound, N-acetylcysteine (NAC), has antioxidative and cytoprotective properties. The objective in this subchronic toxicity study was to identify the prophylactic effect of NAC over histopathological changes and oxidative stress induced by GBH in blood, renal, liver, cardiac, and brain tissues. A sum of 28 male Wistar rats were divided into four equal groups, each containing 7 rats. During the study, group I (control group) was supplied with normal rodent bait and tap water ad libitum. The applied agents were 160 mg/kg NAC to group II, 375 mg/kg as equivalent to 1/10 of lethal dose 50% (LD50) of GBH to group III, and 160 mg/kg of NAC and 375 mg/kg of GBH together once per day as oral gavage to group IV for 8 weeks. While GBH decreased the levels of GSH in blood, liver, kidney, and brain tissues, it considerably increased malondialdehyde levels. On the contrary, these parameters happened to improve in the group supplied with NAC. Besides, it was seen that NAC was observed to improve the histopathologic changes in rat tissues induced by GBH. It was concluded that NAC protects oxidative stress and tissue damage induced by GBH in blood and tissue and this prophylactic effect could be attributed to its antioxidant and free radical sweeper character.

Protective effects of resveratrol on biomarkers of oxidative stress, biochemical and histopathological changes induced by sub-chronic oral glyphosate-based herbicide in rats

The aim of this sub-chronic toxicity study is to determine the protective effects of Resveratrol (Res) on oxidative stress, biochemical and histopathological changes induced by glyphosate-based herbicide (GBH) in the blood, brain, heart, liver and renal tissues. A total of 28 male Wistar rats were equally divided into 4 groups so that each group included 7 rats. In the study, Group I (control group) was given normal rodent feed and tap water ad libitum. Group II (Res group) was given Res 20 mg kg^-1, Group III (GBH group) was given GBH of 375 mg kg^-1 to achieve 1/10 of Lethal Dose 50% (LD50), and Group IV (Res + GBH) was given Res 20 mg kg^-1 and GBH 375 mg kg^-1 with oral gavage once a day for 8 weeks. While GBH decreased the glutathione (GSH) levels in the blood, brain, heart, liver and renal tissues, it significantly increased malondialdehyde (MDA) levels. In contrast, the aforementioned parameters were seen to recover in the group to which Res was administered. Moreover, it was observed that Res improved the histopathological changes induced by GBH in rat tissues. In conclusion, Res prevents oxidative stress caused by GBH by preventing lipid peroxidation (LPO) and boosting the antioxidant defense system and decreases the damage in the brain, heart, liver and renal tissues of Wistar rats.

Ameliorative effect of resveratrol on testicular oxidative stress, spermatological parameters and DNA damage in glyphosate-based herbicide-exposed rats

In this study, the reproductive impacts of being exposed to glyphosate (GLF) and the protective impacts of resveratrol (RES) were assessed in 28 Wistar male rats, which were equally separated into four groups. Control group were fed normal diet without GLF or RES, group II received normal feed containing 20 mg kg-1 daily-1 RES, group III received normal feed containing 375 mg kg-1 daily-1 GLF, and group IV received normal feed containing 375 mg kg-1 daily-1 GLF+20 mg kg-1 daily-1 RES. GLF administration decreased sperm motility, sperm plasma membrane integrity, glutathione level and superoxide dismutase in the testicular tissue of rats. On the other hand, abnormal sperm rate, malondialdehyde level, and DNA damage were detected to be high in the group treated with GLF. The findings indicate that RES protects spermatological parameters and DNA damage, decreases GLF-induced lipid peroxidation, improves the antioxidant defence mechanism and regenerates tissue damage in the testis of rats.

Pancreatic function and histoarchitecture in Wistar rats following chronic exposure to Bushfire®: the mitigating role of zinc

Objectives To assess the toxicopathologic effects of chronic exposure to the glyphosate-based herbicide Bushfire® on the pancreas of Wistar rats and the protective role of zinc. Methods We exposed the rats to daily doses of 14.4 to 750 mg/kg body weight of the glyphosate-based herbicide Bushfire® and to 50 or 100 mg/kg zinc, and measured blood glucose levels and serum insulin levels. Tissue samples were evaluated for histopathological alterations. Results Levels of both blood glucose and serum insulin increased in glyphosate-exposed rats, and moderate to severe degenerative changes were observed in both glandular pancreatic acinar cells and islets of Langerhans in all rats exposed to glyphosate. These effects were prevented by pretreatment with zinc. Conclusion Chronic exposure to glyphosate can alter pancreatic function and histoarchitecture, but zinc supplementation can mitigate these toxicopathologic effects.