Toxicity of glyphosate in feed for weanling piglets and the mechanism of glyphosate detoxification by the liver nuclear receptor CAR/PXR pathway

Melatonin alleviates glyphosate-induced testosterone synthesis inhibition via targeting mitochondrial function in roosters

Glyphosate (GLY) is a widely used herbicide that has been revealed to inhibit testosterone synthesis in humans and animals. Melatonin (MET) is an endogenous hormone that has been demonstrated to promote mammalian testosterone synthesis via protecting mitochondrial function. However, it remains unclear whether MET targets mitochondria to alleviate GLY-inhibited testosterone synthesis in avian. In this study, an avian model using 7-day-old rooster upon chronic exposure to GLY with the treatment of MET was designed to clarify this issue. Data first showed that GLY-induced testicular Leydig cell damage, structural damage of the seminiferous tubule, and sperm quality decrease were mitigated by MET. Transcriptomic analyses of the testicular tissues revealed the potentially critical role of mitophagy and steroid hormone biosynthesis in the process of MET counteracting GLY-induced testicular damage. Also, validation data demonstrated that the inhibition of testosterone synthesis due to GLY-induced mitochondrial dynamic imbalance and concomitant Parkin-dependent mitophagy activation is alleviated by MET. Moreover, GLY-induced oxidative stress in serum and testicular tissue were significantly reversed by MET. In summary, these findings demonstrate that MET effectively ameliorates GLY-inhibited testosterone synthesis by inhibiting mitophagy activation, which provides a promising remedy for the application of MET as a potential therapeutic agent to antagonize reproductive toxicity induced by GLY and similar contaminants.

Oxidized Soybean Oil Evoked Hepatic Fatty Acid Metabolism Disturbance in Rats and their Offspring

The oxidation of fats and oils is an undisputed subject of science, given the effect of oxidized fats and oils on food quality and safety. This study aimed to determine whether maternal exposure to oxidized soybean oil (OSO) causes lipid metabolism disorders in the liver and whether this lipid metabolism disorder can be transmitted to offspring or even worsened. A total of 60 female Sprague-Dawley (SD) rats were divided randomly into four groups in this study. Treatment groups received a pure diet of OSO with a peroxide value of 200, 400, or 800 mEqO2/kg, while the control group received fresh soybean oil (FSO). As for our results, OSO affected serum biochemical parameters in the maternal generation (F0) and induced liver histopathology changes, inflammation, and oxidative stress. Moreover, the expression of genes related to the liver X receptor α (LXRα)─sterol regulatory element binding protein-1c (SREBP-1c) signaling pathway was changed. Similar trends were found in the livers of offspring on postnatal days 21 and 56. In conclusion, exposure to OSO during gestation and lactation can affect liver lipid synthesis. Additionally, it is detrimental to the development of the offspring's liver, affecting fatty acid metabolism and causing liver damage.

Glyphosate-induced autophagy inhibition results in hepatic steatosis via mediating epigenetic reprogramming of PPARα in roosters

Glyphosate (Gly) is the most widely used herbicide with well-defined hepatotoxic effects, but the underlying mechanisms of Gly-induced hepatic steatosis remain largely unknown. In this study, a rooster model combined with primary chicken embryo hepatocytes was established to dissect the progresses and mechanisms of Gly-induced hepatic steatosis. Data showed that Gly exposure caused liver injury with disrupted lipid metabolism in roosters, manifested by significant serum lipid profile disorder and hepatic lipid accumulation. Transcriptomic analysis revealed that PPARα and autophagy-related pathways played important roles in Gly-induced hepatic lipid metabolism disorders. Further experimental results suggested that autophagy inhibition was involved in Gly-induced hepatic lipid accumulation, which was confirmed by the effect of classic autophagy inducer rapamycin (Rapa). Moreover, data substantiated that Gly-mediated autophagy inhibition caused nuclear increase of HDAC3, which altered epigenetic modification of PPARα, leading to fatty acid oxidation (FAO) inhibition and subsequently lipid accumulation in the hepatocytes. In summary, this study provides novel evidence that Gly-induced autophagy inhibition evokes the inactivation of PPARα-mediated FAO and concomitant hepatic steatosis in roosters by mediating epigenetic reprogramming of PPARα.

Influences of Glyphosate Contaminations and Concentrate Feed on Performance, Blood Parameters, Blood Cell Functionality and DNA Damage Properties in Fattening Bulls

Glyphosate (GLY), the active substance in non-selective herbicides, is often found in ruminant feed. The present feeding study aimed to investigate the effects of GLY-contaminated rations and different concentrate feed proportions (CFP) on the health of fattening German Holstein bulls. Bulls were grouped by low (LC) or high (HC) CFP with (GLY_LC, GLY_HC) or without GLY-contaminations (CON_LC, CON_HC) in their rations. Intakes (dry matter, water) and body weight were documented continuously lasting over an average range from 392.2 ± 60.4 kg to 541.2 ± 67.4 kg (mean ± SD). Blood samples collected at the trial's beginning, and after 7 and 15 weeks, were analyzed for hematological and clinical-chemical traits, functional properties of leukocytes, redox parameters and DNA damage. The average GLY exposures of 128.6 (GLY_HC), 213.7 (GLY_LC), 1.3 (CON_HC) and 2.0 µg/kg body weight/d (CON_LC) did not lead to GLY effects for most of the assessed parameters relating to animal health and performance. CFP and time displayed marked influences on most of the experimental parameters such as higher dry matter intake and average daily gain in HC compared with the LC groups. GLY effects were rather weak. However, the observed interactive effects between GLY and CFP and/or time occurring in an inconsistent manner are likely not reproducible. Finally, all animals remained clinically inconspicuous, which brings into question the physiological relevance of putative GLY effects.

Perinatal exposure to high concentration glyphosate-based herbicides induces intestinal apoptosis by activating endoplasmic reticulum stress in offspring

Glyphosate-based herbicides (GBHs), the most widely used pesticide worldwide, have been reported to impair organ function in humans and animals. However, research on the effect of maternal GBHs exposure on the intestinal health of offspring has received little attention. Based on the glyphosate limits defined by Codex Alimentarius Commission and European Food Safety Authority, this study established pregnant sow exposure models to investigate the influence of low (L-GBHs, 20 mg/kg) and high concentration GBHs (H-GBHs, 100 mg/kg) on the intestinal health of offspring and proposed the protective mechanism mediated by betaine. The results showed that the intestinal morphology and barrier function of suckling piglets were damaged in the H-GBHs group. H-GBHs increased the activity of glutathione peroxidase (GPX) and levels of methane dicarboxylic aldehyde (MDA), hydrogen peroxide (H₂O₂) and inflammatory factors (tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-10 (IL-10)) in suckling piglets and activated Nrf2-mediated antioxidant signaling pathway. Subsequently, we found that exposure to H-GBHs triggered endoplasmic reticulum stress (ERS) and further induced apoptosis by upregulating the expression of Bcl-2-associated X protein (Bax), Caspase3, Caspase9 and Caspase12. Moreover, H-GBHs exposure perturbed mitochondrial membrane fusion and electron transport in mitochondrial respiratory chains by increasing the mRNA expression of mitofusin-2 (MFN2) and succinate dehydrogenase subunit A (SDHA), causing mitochondrial dysfunction. Dietary supplementation with betaine provided modest protection against GBHs-induced intestinal damage in suckling piglets. These findings reveal the mechanism of GBHs-induced intestinal damage in offspring, improving our understanding of the risk of GBHs exposure in pregnant women and suggesting the potential protective effects of betaine against GBHs poisoning.

The effects of glyphosate exposure on gene transcription and immune function of the silkworm, Bombyx mori

Glyphosate is a widely used herbicide and crop desiccant. However, whether its extensive use has any effect on the species diversity of nontarget organisms is still unclear. In this study, we used the silkworm, Bombyx mori, as the research subject, and performed RNA sequencing to analyze the transcriptional profile of silkworm midgut after exposure to glyphosate at 2975.20 mg/L (a concentration commonly used at mulberry fields). A total of 125 significantly differentially expressed genes (DEGs) were detected in the midgut of glyphosate-exposed silkworm (q < 0.05), of which 53 were upregulated and 72 were downregulated. Gene ontology enrichment analysis showed that the DEGs were mainly enriched in biological process, cellular component, and molecular function. Kyoto encyclopedia of genes and genomes analysis showed that the differential genes were mainly related to oxidative stress, nutrient metabolism, and immune defense pathways, including oxidative stress-related Cat and Jafrac1, nutrient metabolism-related Fatp and Scpx, and immune-related CYP6AN2, UGT40B4, CTL11, serpin-2, and so forth. Experimental verification showed that glyphosate exposure led to a 4.35-fold increase in the mortality of silkworm after Beauveria bassiana infection, which might be caused by the decreased PO (phenoloxidase) activity and impaired immunity. These results provide evidence for the potential effects of residue glyphosate on the physiological functions of silkworm, and also provide a reference for the biosafety evaluation of glyphosate.

Glyphosate based-herbicide disrupts energy metabolism and activates inflammatory response through oxidative stress in mice liver

Glyphosate, the most widely used herbicide worldwide, has been reported to cause hepatotoxicity. However, these systematic mechanisms remain poorly understood. Here, we investigated the effects of glyphosate-based herbicides (GBH) on liver toxicity in mice exposed to 0, 50, 250, and 500 mg/kg/day GBH for 30 d. Pathological and ultrastructural changes, serum biochemical indicators, oxidative stress state, and transcriptome and key protein alterations were performed to describe the hepatic responses to GBH. GBH induced hepatocytes structural alterations, vacuolation, and inflammatory, mitochondrial swelling and vacuolization; damaged liver function and aggravated oxidative stress; blocked the respiratory chain, promoted gluconeogenesis, fatty acid synthesis and elongation, and activated complement and coagulation cascades system (CCCS) in the liver. Moreover, SOD, H₂O₂, and MDA were negatively correlated with the CxI and CxIV genes, but positively correlated with the genes in glucolipid metabolism and CCCS pathways; however, the opposite results were observed for CAT, GSH-Px, and T-AOC. Overall, this study revealed the systematic mechanism underlying hepatotoxicity caused by GBH, providing new insights into understanding the hepatotoxicity of organophosphorus pesticide.

Perinatal exposure to glyphosate-based herbicides impairs progeny health and placental angiogenesis by disturbing mitochondrial function

Glyphosate-based herbicides (GBHs) are the most widely used pesticide worldwide and can provoke placental injury. However, whether and how GBHs damage angiogenesis in the placenta is not yet known. This work evaluated the safety of glyphosate on pregnant sows based on the limit level by governments and investigated the effects and mechanism of Low-GBHs (20 mg/kg) and High-GBHs (100 mg/kg) exposure on placental angiogenesis. Results showed that gestational exposure to GBHs decreased placental vessel density and cell multiplication by interfering with the expression of VEGFA, PLGF, VEGFr2 and Hand2 (indicators of angiogenesis), which may be in relation to oxidative stress-induced disorders of mitochondrial fission and fusion as well as the impaired function of the mitochondrial respiratory chain. Additionally, GBHs destroyed barrier function and nutrient transport in the placenta, and was accompanied by jejunum oxidative stress in newborn piglets. However, GBHs exposure had no significant differences on sow reproductive performance. As a natural antioxidant, betaine treatment protected placenta and newborn piglets against GBHs-induced damage. In conclusion, GBHs impaired placental angiogenesis and function and further damaged the health of postnatal progeny, these effects may be linked to mitochondrial dysfunction. Betaine treatment following glyphosate exposure provided modest relief.

Investigation of the toxicity of a glyphosate-based herbicide in a human liver cell line: Assessing the involvement of Nrf2 pathway and protective effects of vitamin E and α-lipoic acid

Glyphosate-based herbicides (GBHs) are the most widely used herbicides all over the world and has gained more attention in recent years because of health safety concerns. In this study, Roundup, one of the most popular glyphosate formulations, was used to evaluate cytotoxic, oxidative stress and apoptosis inducing effects of GBHs in a human hepatocellular cell line (HepG2). Roundup was shown to significantly increase cellular reactive oxygen species (ROS) levels, which lead to activation of the nuclear factor-erythroid-2-related factor 2 (Nrf2) antioxidant defense pathway including reduced levels of heme oxygenase 1 (HO-1). Furthermore, Roundup was found to induce apoptosis and further analysis confirmed involvement of a mitochondrial-dependent pathway verified by increased Bax/Bcl-2 ratios. Investigation of the protective effects of antioxidants vitamin E (Vit E) and α-lipoic acid (LA) against Roundup toxicity showed that both antioxidants significantly reduced the cytotoxicity, ROS formation, HO-1 downregulation, and apoptosis and that Vit E did so more efficiently than LA. In conclusion, our findings highlight the ROS producing and apoptosis inducing effects associated with GBHs, the activation of Nrf2 pathway as a defense mechanism and the protective effects of Vit E and LA against GBH toxicity.

Trehalose prevents glyphosate-induced testicular damage in roosters via its antioxidative properties

Glyphosate (GLY), an active ingredient of the most commonly used herbicide, when in crops and feed, is deleterious to male reproductive health. Trehalose (Tre), a naturally non-reducing disaccharide, is shown to counteract the adverse stresses due to its antioxidation effect. Thus, this study was designed to investigate whether Tre can improve GLY-induced testicular damage via suppressing oxidative stress. 60 healthy Hy-Line Brown breeder roosters were utilized to assess the protective effects of Tre supplementation against testicular oxidative damage caused by GLY. Data showed that Tre administration significantly alleviated GLY- induced reduction in testis weight, decreased GLY level in the testis tissues, and alleviated GLY-caused testicular pathological damage. Concurrently, GLY treatment significantly elevated serum malondialdehyde (MDA) and testicular reactive oxygen species (ROS) levels, decreased serum total anti-oxidation capacity (T-AOC), catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) levels, which were all notably reversed by Tre administration. Moreover, GLY- inhibited nuclear factor erythroid 2-related factor 2 (Nrf2) pathway in rooster testis, a master regulator of oxidative stress, was markedly recovered by Tre administration. In summary, these findings demonstrated that Tre can prevent GLY-induced testicular damage in roosters by ameliorating oxidative stress.

Dihydroartemisinin alleviates deoxynivalenol induced liver apoptosis and inflammation in piglets

Deoxynivalenol (DON) is one of the mycotoxins that contaminate cereals and feed, thereby endangering human and animal health. Dihydroartemisinin (DHA), a derivative of artemisinin, has anti-inflammatory and antioxidant functions in addition to anti-malaria and anti-cancer. The purpose of this study was to investigate the effects of DHA on alleviating liver apoptosis and inflammation induced by DON in piglets. The experimental design followed a 2 (normal diet and DON-contaminated diet) × 2 (with and without supplementation of DHA) factorial arrangement. 36 weaned piglets were subjected to a 21-day experiment. Results showed that DON increased ALT activity, the levels of TNF-α, IL-1β and IL-2, and reduced the levels of total protein (TP) and albumin (ALB) in the serum. However, DHA decreased the levels of TNF-α, IL-1β and IL-2, and increased the levels of TP and ALB. Also, DON decreased glutathione (GSH) content and catalase (CAT) activity, and increased methane dicarboxylic aldehyde (MDA) content. But GSH content was increased by DHA. In addition, DHA decreased DON-induced increase in apoptosis rate of hepatocytes. Furthermore, DON activated death receptor pathway to promote apoptosis by up-regulating the protein expression of FasL and caspase-3, and the mRNA expression of FasL, TNFR1, caspase-8, Bid, Bax, CYC and caspase-3. However, DHA reduced caspase-3 protein expression, as well as the mRNA expression of FADD, Bid, Bax, CYC and caspase-3. Besides, DON also activated TNF/NF-κB pathway to induce an inflammatory response by up-regulating TNF-α protein expression, and the mRNA expression of TNFR1, RIP1, IKKβ, IκBα, IL-1β and IL-8. Nevertheless, DHA reduced the mRNA expression of RIP1, IκBα, NF-κB, IL-1β and IL-6, and the protein expression of TNF-α and NF-κB. In conclusion, DHA improved DON-induced negative effects on serum biochemical parameters and inflammatory cytokine levels, hepatic antioxidant capacity, hepatic apoptosis and inflammation.

Maternal oxidized soybean oil exposure in rats during lactation damages offspring kidneys via Nrf2/HO-1 and NF-κB signaling pathway

BACKGROUND

Cooking oil is an indispensable component of the human diet. However, oils usually undergo thermal oxidation. Oxidized soybean oil (OSO) has been shown to have detrimental effects on humans and has emerged as a root cause of many chronic diseases. The objective of this work was to evaluate the effects of puerpera exposure to OSO on kidney damage in the mother and offspring using lactating rats as an experimental model.

RESULTS

Pathological sections and ultrastructure showed that OSO exposure resulted in various levels of damage to lactating rats and their offspring. OSO induced oxidative stress in the kidneys of lactating rats, as evidenced by increased levels of hydrogen peroxide, interleukin (IL)-1β, and IL-8. OSO increased the activities of glutathione peroxidase and superoxide dismutase. OSO upregulated the expression of apoptosis-related genes, nuclear factor-erythroid 2-related factor 2 (Nrf2), and nuclear factor κB-related inflammatory factor genes. In the offspring of the OSO-exposed mothers, hydrogen peroxide, malondialdehyde, IL-6, and tumor necrosis factor-alpha contents were increased. Furthermore, OSO enhanced the levels of Nrf2, NAD(P)H quinone oxidoreductase 1, heme oxygenase 1, and p65 and decreased B-cell lymphoma 2.

CONCLUSION

These findings indicated that the kidneys of two generations of rats were compromised by oxidative damage when fed OSO during lactation. This study provides evidence for increasing the genes expression of the Nrf2/heme oxygenase 1 pathway to alleviate the kidney damage caused by OSO in the mother and offspring. © 2021 Society of Chemical Industry.

Advances in organophosphorus pesticides pollution: Current status and challenges in ecotoxicological, sustainable agriculture, and degradation strategies

Organophosphorus pesticides (OPPs) are one of the most widely used types of pesticide that play an important role in the production process due to their effects on preventing pathogen infection and increasing yield. However, in the early development and application of OPPs, their toxicological effects and the issue of environmental pollution were not considered. With the long-term overuse of OPPs, their hazards to the ecological environment (including soil and water) and animal health have attracted increasing attention. Therefore, this review first clarified the classification, characteristics, applications of various OPPs, and the government's restriction requirements on various OPPs. Second, the toxicological effects and metabolic mechanisms of OPPs and their metabolites were introduced in organisms. Finally, the existing methods of degrading OPPs were summarized, and the challenges and further addressing strategy of OPPs in the sustainable development of agriculture, the environment, and ecology were prospected. However, methods to solve the environmental and ecological problems caused by OPPs from the three aspects of use source, use process, and degradation methods were proposed, which provided a theoretical basis for addressing the stability of the ecological environment and improving the structure of the pesticide industry in the future.

Oxidative Stress and Metabolism: A Mechanistic Insight for Glyphosate Toxicology

Glyphosate (GLYP) is a widely used pesticide; it is considered to be a safe herbicide for animals and humans because it targets 5-enolpyruvylshikimate-3-phosphate synthase. However, there has been increasing evidence that GLYP causes varying degrees of toxicity. Moreover, oxidative stress and metabolism are highly correlated with toxicity. This review provides a comprehensive introduction to the toxicity of GLYP and, for the first time, systematically summarizes the toxicity mechanism of GLYP from the perspective of oxidative stress, including GLYP-mediated oxidative damage, changes in antioxidant status, altered signaling pathways, and the regulation of oxidative stress by exogenous substances. In addition, the metabolism of GLYP is discussed, including metabolites,metabolic pathways, metabolic enzymes, and the toxicity of metabolites. This review provides new ideas for the toxicity mechanism of GLYP and proposes effective strategies for reducing its toxicity.

Response of the nuclear xenobiotic receptors to alleviate glyphosate-based herbicide-induced nephrotoxicity in weaned piglets

Glyphosate-based herbicides (GBHs) are widely used worldwide. Glyphosate (GLP) is the main active component of GBHs. The presence of GBH residues in the environment has led to the exposure of animals to GBHs, but the mechanisms of GBH-induced nephrotoxicity are not clear. This study investigated the effects of GBHs on piglet kidneys. Twenty-eight healthy female hybrid weaned piglets (Duroc × Landrace × Yorkshire) with an average weight of 12.24 ± 0.61 kg were randomly divided into four treatment groups (n=7 piglets/group) that were supplemented with Roundup® (equivalent to GLP concentrations of 0, 10, 20, and 40 mg/kg) for a 35-day feeding trial. The results showed that the kidneys in the 40-mg/kg GLP group suffered slight damage. Roundup® significantly decreased the activity of catalase (CAT) (P=0.005) and increased the activity of superoxide dismutase (SOD) (P=0.029). Roundup® increased the level of cystatin-C (Cys-C) in the plasma (linear, P=0.002 and quadratic, P=0.015). The levels of neutrophil gelatinase-associated lipocalin (NGAL) in plasma increased linearly (P=0.007) and quadratically (P=0.003) as the dose of GLP increased. The mRNA expression of intercellular cell adhesion molecule-1 (ICAM-1) in the 20-mg/kg GLP group was increased significantly (P<0.05). There was a significant increase in the mRNA levels of pregnenolone X receptor (PXR), constitutive androstane receptor (CAR), and uridine diphosphate glucuronosyltransferase 1A3 (UGT1A3) (P<0.05). Our findings found that kidney nuclear xenobiotic receptors (NXRs) may play an important role in defense against GBHs.

Dietary Curcumin Alleviated Aflatoxin B1-Induced Acute Liver Damage in Ducks by Regulating NLRP3-Caspase-1 Signaling Pathways

Aflatoxin B1 (AFB1) is a mycotoxin widely distributed in animal feed and human food; it represents a serious threat to human and animal health. This study investigates the mechanism by which dietary curcumin protected liver against acute damage caused by AFB1 administration in ducks. One-day-old male ducks (n = 450) were randomly assigned to three groups, the control group, the AFB1 group, and the AFB1 + curcumin group; the first group were fed with basic diet, while the third group was fed basic diet containing 500 mg/kg curcumin. Ducks in the AFB1 group and AFB1 + curcumin group were challenged with AFB1 at the age of 70 days. The results show that AFB1 administration caused liver damage, increased CYP450 content and AFB1-DNA adducts in the liver, and induced oxidative stress and inflammatory response in the liver. Dietary curcumin significantly inhibited the generation of H₂O₂ and MDA in liver, activated the Nrf2-ARE signaling pathway, and suppressed the NLRP3–caspase-1 signaling pathway in the liver of ducks. Conclusively, curcumin in diet could protect duck liver against the generation of AFB1-DNA adducts, toxicity, oxidation stress and inflammatory response induced by AFB1 through regulating the NLRP3–caspase-1 signaling pathways, demonstrating that curcumin is a potential feed additive agent to reduce the serious harmful effects of AFB1 on duck breeding.

Dietary phytochemicals as modulators of human pregnane X receptor

As a promiscuous xenobiotic sensor, pregnane X receptor (PXR) plays a crucial role in drug metabolism. Since dietary phytochemicals exhibit the potential to modulate human PXR, this review aims to summarize the plant-derived PXR modulators, including agonists, partial agonists, and antagonists. The crystal structures of the apo and ligand-bound forms of PXR especially that of PXR complexed with binary mixtures are summarized, in order to provide the structural basis for PXR binding promiscuity and synergistic activation of PXR by composite ligands. Furthermore, this review summarizes the characterized agonists, partial agonists, and antagonists of human PXR from botanical source. Contrary to PXR agonists, there are only a few antagonists obtained from botanical source due to the promiscuity of PXR. It is worth noting that trans-resveratrol and a series of methylindoles have been identified as partial agonists of PXR, both in activating PXR function, but also inhibiting the effect of other PXR agonists. Since antagonizing PXR function plays a crucial role in the prevention of drug-drug interactions and improvement of therapeutic efficacy, further research is necessary to screen more plant-derived PXR antagonists in the future. In summary, this review may contribute to understanding the roles of phytochemicals in food-drug and herb-drug interactions.

Jekyll and Hyde: nuclear receptors ignite and extinguish hepatic oxidative milieu

Nuclear receptors (NRs) are ligand-binding transcription factors that regulate gene networks and physiological responses. Often oxidative stress precedes the onset of liver diseases, and Nrf2 is a key regulator of antioxidant pathways. NRs crosstalk with Nrf2, since NR activation can influence the oxidative milieu by modulating reductive cellular processes. Diet and xenobiotics also regulate NR expression and activity, suggesting a feedback loop. Depending on the tissue context and cues, NRs either increase or decrease toxicity and oxidative damage. Many FDA-approved drugs target NRs, and one could potentially repurpose them to ameliorate reactive oxygen species (ROS). Here, we discuss how several NRs modulate oxidative stress subsequent to diet, organic pollutants, and drug-induced injury to the liver.

Maternal Exposure to Oxidized Soybean Oil Impairs Placental Development by Modulating Nutrient Transporters in a Rat Model

INTRODUCTION

As an exogenous food contaminant, dietary oxidized lipid impairs growth and development, and triggers chronic diseases in humans or animals. This study explores the effects of soybean oil with different oxidative degree on the placental injury of gestational rats.

METHODS AND RESULTS

Thirty-two female adult rats are randomly assigned to four groups. The control group is fed the purified diet with fresh soybean oil (FSO), and the treatment groups are fed purified diets with lipid content replaced by oxidized soybean oil (OSO) at 200, 400, and 800 mEqO2 kg-1 from conception until delivery. On day 20 of gestation, OSO decreased placental and embryonic weights as the oxidative degree increased linearly and quadratically. The expression of Bax showed a linear increase, and Bcl-2 decreased as the oxidative degree increased. The expression of Fosl1 and Esx1 is linearly and quadratically decreased in OSO-treated groups than FSO group. OSO decreased the level of IL-10 but increased expression of IL-1β in placenta and plasma. OSO remarkably upregulates levels of Fatp1 and Glut1 and decreases expression of Snat2 and Glut3.

CONCLUSION

OSO aggravates placental injury by modulating nutrient transporters and apoptosis-related genes, impedes placental growth and development, and ultimately leads to the decrease of fetal weight.

Mechanisms of deleterious effects of some pesticide exposure on pigs

The increase in the size of the global population increases the food and energy demand, making the use of pesticides in agricultural and livestock industries unavoidable. Exposure to pesticides can be toxic to the non-target species, such as humans, wildlife, and livestock, in addition to the target organisms. Various chemicals are used in the livestock industry to control harmful organisms, such as insects, weeds, and parasites. Pigs are one of the most important food sources for humans. In addition, pigs can be used as promising models for assessing the risk of absorption of environmental pollutants through the skin and oral exposure since they are physiologically similar to humans. Exposure to numerous environmental pollutants, such as mycotoxins, persistent organic pollutants, and heavy metals, has been reported to adversely affect growth, fertility, and endocrine homeostasis in pigs. Various pesticides have been observed in porcine tissues, blood, urine, and processed foods; however, there is a lack of comprehensive understanding of their effects on porcine health. This review provides a comprehensive description of the characteristics of pesticides that pigs can be exposed to and how their exposure affects porcine reproductive function, intestinal health, and endocrine homeostasis in vivo and in vitro.

Exposure to oxidized soybean oil induces mammary mitochondrial injury in lactating rats and alters the intestinal barrier function of progeny

Similar to other food contaminants, dietary oxidized soybean oil (OSO) is also a toxic xenobiotic for animal and human nutrition. This research evaluated the effects of maternal OSO exposure during lactation on mammary mitochondrial injury and intestinal barrier of sucking progeny. Twenty-four female adult SD rats were fed a fresh soybean oil (FSO) homozygous diet (7%) or an OSO homozygous diet (7%) during lactation. On day 21 of lactation, upregulated mRNA expression of Sirt3 and PRDX3 and downregulated mRNA expression of Mfn2 were observed in mammary tissues in the OSO group compared to the control group (P < 0.05). Maternal OSO consumption increased the FasL transcriptional level in the mammary glands of rat dams (P < 0.05), while the mRNA expression of Bax, Bcl-2, Caspase3, and Fas was not different from that in the control group (P > 0.05). OSO enhanced the Nrf2 transcriptional level and decreased the expression of Keap1 and PPARα in mammary tissues (P < 0.05). In addition, the contents of CAT, MDA, SOD were not affected by dietary OSO (P > 0.05), while the concentration of H2O2 was significantly decreased in the OSO-treated mammary glands of rat dams (P < 0.05). Maternal OSO exposure during lactation did not affect the organ coefficients of pups (P > 0.05). However, maternal OSO consumption influenced the intestinal tight junction protein expression of progeny (P < 0.05). In summary, the present study demonstrated that dietary OSO may aggravate mammary injury and mitochondria dysfunction, but the OSO-induced damage was self-alleviating via the promotion of Sirt3 and PRDX3 expression and further scavenging of oxidative products.

Novel insights into cytochrome P450 enzyme and solute carrier families in cadmium-induced liver injury of pigs

Cadmium (Cd) is a typical pollutant and carcinogen in environment. Exposure assessment of contaminants is an important component of occupational and environmental epidemiological studies. Early studies of Cd have focused on aquatic animals, chickens and rats. However, toxicological evaluation of Cd in pigs has not been reported. Therefore, twelve pigs were randomly divided into two groups (n = 6): the control group and the Cd group (Cd content: 15 ± 0.242 mg/kg feed) in this study, the experimental period was 30 d, and the toxic effects of Cd on the liver of weanling piglets were examined by antioxidant function, liver function, Cd content, histological examination and transcriptomics. The results showed that the changes of antioxidant function, liver function and Cd content were significant in the liver. Transcriptional profiling results showed that 399 differentially expressed genes (DEGs) were significantly up-regulated while 369 DEGs were remarkably down-regulated in Cd group, and which were concentrated in three ontologies: molecular function, cellular component and biological processes. Interestingly, significant changes in some genes of the cytochrome P450 enzyme (CYP450) and solute carrier (SLC) families have been observed and were consistent with qRT-PCR results. In conclusion, Cd could cause liver injury in weanling piglets and change the transcriptomic characteristics of liver. CYP450 and SLC families play an indispensable role in Cd-mediated hepatotoxicity. Importantly, changes in mRNA levels of CYP2B22, CYP7A1, CYP8B1, SLC26A8, SLC11A1, SLC27A2 and SLC22A7 induced by Cd have been reported for the first time. Our findings will provide a new insight for better assessing the mechanism of Cd toxicity to the liver.

Ammonia exposure causes the disruption of the solute carrier family gene network in pigs

Ammonia is the main harmful gas in livestock houses. However, the toxic mechanism of ammonia is still unclear. Therefore, we examined the effects of ammonia exposure on different tissues of fattening pigs by histological analysis and transcriptome techniques in this study. The results showed that there were varying degrees of pathological changes in liver, kidney, hypothalamus, jejunum, lungs, spleen, heart and trachea of fattening pigs under ammonia exposure. Notably, the extent of damage in liver, kidney, jejunum, lungs, hypothalamus and trachea was more severe than that in heart and spleen. Transcriptome results showed that ammonia exposure caused changes in 349, 335, 340, 229, 120, 578, 407 and 115 differentially expressed genes in liver, kidney, spleen, lung, trachea, hypothalamus, jejunum and heart, respectively. Interestingly, the changes in solute vector (SLC) family genes were found in all 8 tissues, and the verified gene results (SLC11A1, SLC17A7, SLC17A6, SLC6A4, SLC22A7, SLC25A3, SLC28A3, SLC7A2, SLC6A6, SLC38A5, SLC22A12, SLC34A1, SLC26A1, SLC26A6, SLC27A5, SLC22A8 and SLC44A4) were consistent with qRT-PCR results. In conclusion, ammonia exposure can cause pathological changes in many tissues and organs of fattening pigs and changes in the SCL family gene network. Importantly, the SCL family is involved in the toxic mechanism of ammonia. Our findings will provide a new insight for better assessing the mechanism of ammonia toxicity.

Effects of glyphosate residues and different concentrate feed proportions in dairy cow rations on hepatic gene expression, liver histology and biochemical blood parameters

Glyphosate (GLY) is worldwide one of the most used active substances in non-selective herbicides. Although livestock might be orally exposed via GLY-contaminated feedstuffs, not much is known about possible hepatotoxic effects of GLY. As hepatic xenobiotic and nutrient metabolism are interlinked, toxic effects of GLY residues might be influenced by hepatic nutrient supply. Therefore, a feeding trial with lactating dairy cows was conducted to investigate effects of GLY-contaminated feedstuffs and different concentrate feed proportions (CFP) in the diets as tool for varying nutrient supply to the liver. For this, 61 German Holstein cows (207 ± 49 days in milk; mean ± standard deviation) were either fed a GLY-contaminated total mixed ration (TMR, GLY groups, mean GLY intake 122.7 μg/kg body weight/day) or control TMR (CON groups, mean GLY intake 1.2 μg/kg body weight/day) for 16 weeks. Additionally, both groups were further split into subgroups fed a lower (LC, 30% on dry matter basis) or higher (HC, 60% on dry matter basis) CFP resulting in groups CONHC (n = 16), CONLC (n = 16), GLYHC (n = 15), GLYLC (n = 14). Blood parameters aspartate aminotransferase, γ-glutamyltransferase, glutamate dehydrogenase, cholesterol, triglyceride, total protein, calcium, phosphorus, acetic acid and urea and histopathological evaluation were not influenced by GLY, whereas all mentioned parameters were at least affected by time, CFP or an interactive manner between time and CFP. Total bilirubin blood concentration was significantly influenced by an interaction between GLY and CFP with temporarily elevated concentrations in GLYHC, whereas the biological relevance remained unclear. Gene expression analysis indicated 167 CFP-responsive genes, while seven genes showed altered expression in GLY groups compared to CON groups. Since expression changes of GLY-responsive genes were low and liver-related blood parameters changed either not at all or only slightly, the tested GLY formulation was considered to have no toxic effects on the liver of dairy cows.

Regulation of CAR and PXR Expression in Health and Disease

Pregnane X receptor (PXR, NR1I2) and constitutive androstane receptor (CAR, NR1I3) are members of the nuclear receptor superfamily that mainly act as ligand-activated transcription factors. Their functions have long been associated with the regulation of drug metabolism and disposition, and it is now well established that they are implicated in physiological and pathological conditions. Considerable efforts have been made to understand the regulation of their activity by their cognate ligand; however, additional regulatory mechanisms, among which the regulation of their expression, modulate their pleiotropic effects. This review summarizes the current knowledge on CAR and PXR expression during development and adult life; tissue distribution; spatial, temporal, and metabolic regulations; as well as in pathological situations, including chronic diseases and cancers. The expression of CAR and PXR is modulated by complex regulatory mechanisms that involve the interplay of transcription factors and also post-transcriptional and epigenetic modifications. Moreover, many environmental stimuli affect CAR and PXR expression through mechanisms that have not been elucidated.

Engineered glyphosate oxidase coupled to spore-based chemiluminescence system for glyphosate detection

The extensive and intensive utilization of glyphosate (Glyp) caused public concerns on the potential risk of environment and health resulted from the chemical residues. Therefore, the development of a high-selective, low-cost and easy-operation Glyp detection methods is highly desired. Screening highly selective enzymes by directed evolution is important in practical applications. Herein, a glyphosate oxidase (GlypO) preferring substrate Glyp to produce H2O2 was obtained via directed evolution from glycine oxidase obtained from Bacillus cereus (BceGO). The catalytic efficiency, specificity constant, and affinity enhancement factor of GlypO toward Glyp were increased by 2.85 × 103-fold; 2.25 × 105-fold; and 9.64 × 104-fold, respectively, compared with those of BceGO. The catalytic efficiency toward glycine decreased by 78.60-fold. The spores of Bacillus subtilis (B. subtilis) effectively catalyzed luminol-H2O2 reaction to create excellent chemiluminescence (CL) signal because CotA-laccase exists on their surface. Based on these findings, a new CL biosensor via coupling to biological reaction system was presented for Glyp detection. The CL biosensor exhibited several advantages, such as eco-friendliness, low cost, high selectivity and sensitivity, and good practical application prospects for environmental pollution control.

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.