Effects of simultaneous repeated exposure at high levels of arsenic and malathion on hepatic drug-biotransforming enzymes in broiler chickens

Resveratrol alleviates inorganic arsenic-induced ferroptosis in chicken brain via activation of the Nrf2 signaling pathway

Inorganic arsenic (iAs) is a well-recognized environmental pollutant that induces severe brain injury in humans and animals. The antioxidant, anti-inflammatory, and anti-ferroptotic effects of resveratrol (Res) were demonstrated in multiple animal experiments. In order to investigate the protective effect of Res on iAs-induced chicken brain injury, the 40 chickens (19-d-old, female) brain injury model was established by oral administration of iAs (30 mg/L NaAsO2) for 6 weeks. All chickens had free access to both food and water during the experiment. The biochemical indices, hematoxylin-eosin staining, and related protein levels of oxidative stress, inflammation and ferroptosis were then determined. Our results indicated that Res (1000 mg/kg) alleviated the iAs-induced brain injury after 6 weeks of oral administration, primarily by reducing the interleukin-1β mRNA expression and nuclear factor kappa B and malondialdehyde level, and increasing the antioxidant enzyme activity and the mRNA expression of nuclear factor erythroid 2-related factor 2 (Nrf2). Taken together, our study demonstrates that Res effectively inhibits iAs-induced oxidative stress and ferroptosis by mediating the Nrf2 signaling pathway, thereby alleviating iAs-induced brain injury in chickens. This is the first time that the amelioration effects of Res on the iAs-induced brain have been investigated from multiple perspectives.

Chronic arsenic exposure-provoked biotoxicity involved in liver-microbiota-gut axis disruption in chickens based on multi-omics technologies

INTRODUCTION

Arsenic has been ranked as the most hazardous substance by the U.S. Agency for Toxic Substances and Disease Registry. Environmental arsenic exposure-evoked health risks have become a vital public health concern worldwide owing to the widespread existence of arsenic. Multi-omics is a revolutionary technique to data analysis providing an integrated view of bioinformation for comprehensively and systematically understanding the elaborate mechanism of diseases.

OBJECTIVES

This study aimed at uncovering the potential contribution of liver-microbiota-gut axis in chronic inorganic arsenic exposure-triggered biotoxicity in chickens based on multi-omics technologies.

METHODS

Forty Hy-Line W-80 laying hens were chronically exposed to sodium arsenite with a dose-dependent manner (administered with drinking water containing 10, 20, or 30 mg/L arsenic, respectively) for 42 d, followed by transcriptomics, serum non-targeted metabolome, and 16S ribosomal RNA gene sequencing accordingly.

RESULTS

Arsenic intervention induced a serious of chicken liver dysfunction, especially severe liver fibrosis, simultaneously altered ileal microbiota populations, impaired chicken intestinal barrier, further drove enterogenous lipopolysaccharides translocation via portal vein circulation aggravating liver damage. Furtherly, the injured liver disturbed bile acids (BAs) homoeostasis through strongly up-regulating the BAs synthesis key rate-limiting enzyme CYP7A1, inducing excessive serum total BAs accumulation, accompanied by the massive synthesis of primary BA-chenodeoxycholic acid. Moreover, the concentrations of secondary BAs-ursodeoxycholic acid and lithocholic acid were markedly repressed, which might involve in the repressed dehydroxylation of Ruminococcaceae and Lachnospiraceae families. Abnormal BAs metabolism in turn promoted intestinal injury, ultimately perpetuating pernicious circle in chickens. Notably, obvious depletion in the abundance of four profitable microbiota, Christensenellaceae, Ruminococcaceae, Muribaculaceae, and Faecalibacterium, were correlated tightly with this hepato-intestinal circulation process in chickens exposed to arsenic.

CONCLUSION

Our study demonstrates that chronic inorganic arsenic exposure evokes liver-microbiota-gut axis disruption in chickens and establishes a scientific basis for evaluating health risk induced by environmental pollutant arsenic.

Characterisation of UDP-glucuronosyltransferase activity in sea turtle Chelonia mydas

Uridine diphosphate glucuronosyltransferase (UGT) enzymes conjugate many lipophilic chemicals, such as drugs, environmental contaminants, and endogenous compounds, promoting their excretion. The complexity of UGT kinetics, and the location of enzyme active site in endoplasmic reticulum lumen, requires an accurate optimisation of enzyme assays.In the present study, we characterised UGT activity in liver microsomes of green turtles (Chelonia mydas), an endangered species. The conditions for measuring UGT activity were standardised through spectrofluorimetric methods, using the substrates 4-methylumbelliferone (4-MU) and uridine diphosphate glucuronic acid (UDPGA) at 30 °C and pH 7.4.The green turtles showed UGT activity at the saturating concentrations of substrates of 250 µM to 4-MU and 7 mM to UDPGA. The alamethicin, Brij^®58, bovine serum albumin (BSA), and magnesium increased UGT activity. The assay using alamethicin (22 µg per mg of protein), magnesium (1 mM), and BSA (0.25%) reached the highest V_max (1203 pmol·min^-1mg·protein^-1). Lithocholic acid and diclofenac inhibited UGT activity in green turtles.This study is the first report of UGT activity in the liver of green turtles and provides a base for future studies to understand the mechanisms of toxicity by exposure to contaminants in this charismatic species.

Toxicity evaluation of pesticide chlorpyrifos in male Japanese quails (Coturnix japonica)

In the current study, chlorpyrifos was used as a test chemical to evaluate its possible toxicological effect on birds. A total of 45 adult male Japanese quails were divided into five groups (A to E). Each group, containing 9 birds was further divided into 3 sub-groups (containing 3 birds each). Group A served as control, while all other groups and sub-groups were exposed to selected pesticide for different trial periods. Chlorpyrifos sub-lethal doses were orally administered daily at the rate of 3, 6, 9, and 12 mg/kg body weight per day to group B, C, D, and E, respectively. Birds were kept under observation for behavioral changes throughout the trial periods. Clinical signs, histological alterations, genotoxicity, and blood biochemical alterations were recorded after each 15-day trial. Mild to moderate clinical signs like staggering gait, tremors, diarrhea, dullness, less frequency of crowing, and decrease foam production were observed in group D and E throughout the study. The changes in the body weight gain and blood biochemical parameters among different groups at a given trial period were insignificant. The appearance of micronuclei in group E birds was more significant, indicating that nucleus damage was dose-dependent while to lesser extent duration-dependent. The comet assay showed significant dose- and duration-dependent DNA damage among various groups. In comparison with control group, extensive histological degenerative alterations in the liver, testes, and kidneys were observed in birds of group D and E, where mild to severe alteration like congestion, vacuolation, necrosis, apoptosis, karyopyknosis, extensive degeneration, and alteration in many cellular structures were noticeable.

Protective potential of Opuntia microdasys flower decoction on fructose-alloxan-induced diabetic rats on kidney and pancreas: chemical and immunohistochemical analyses

Diabetes is a serious condition that is linked to the development of oxidative stress causing among many other effects, kidney failure and pancreatic disorders. However, traditional plant-based remedies can be considered an alternative to diabetes healing. In this context, this study was oriented towards evaluating the protective effect of the flowers of Opuntia microdasys Lehm. collected in Tunisia at a biochemical and histological level on kidneys and pancreas of a type 2 diabetic rats. Renal and pancreatic toxicities were induced in diabetic male Wistar rats by fructose alloxan. Diabetic rats were treated with an extract obtained from flowers collected at post-flowering stage (OFP) (100 and 200 mg kg^-1 bw) and metformin (100 mg kg^-1 bw) for 28 days. Oral administration of OFP at 200 mg kg^-1 bw showed significant reduction of the uric acid, urea, creatinine, amylase, lipase, and glycated hemoglobin (HbAl_c). The levels of SOD, CAT, and GP_x were increased, while protein carbonyls and lipid peroxidation TBARS levels were reduced in the kidney and pancreas. The altered kidney and pancreas histology were restored in rats treated with OFP. Thus, the present study demonstrated that OFP has antihyperglycemic activity in fructose-alloxan-induced diabetic rats.

Effects of 4-nonylphenol in drinking water on the reproductive capacity of Japanese quails (Coturnix japonica)

4-nonylphenol (4-NP), a major degradation product of Nonylphenol ethoxylates (NPEOs), is widespread in environment. In this study, the effects of long-term 4-NP exposure in drinking water on Japanese quails (Coturnix japonica) were investigated. A total of 45 quails were evenly divided into 15 groups and administrated with various doses (0.1 μg L^-1, 1.0 μg L^-1, 10 μg L^-1 and 100 μg L^-1, which reflected the environmental concentrations of 4-NP) of 4-NP in drinking water. The results showed that 4-NP in drinking water had no effect on quails' food intake, but significantly decreased the quails' body weights (P < 0.05) in a time- and dose-dependent manner. The egg fertilization rates were also significantly decreased (P < 0.05) in all treatment groups. Moreover, the hatchability was significantly reduced (P < 0.05) in 10 μg L^-1 and 100 μg L^-1 groups, and the 14 d survival rates of young quails were significantly decreased (P < 0.05) in 1.0 μg L^-1, 10 μg L^-1 and 100 μg L^-1 groups. Damaged spermatogenesis in male quails was observed in all treatment groups. Therefore, administration of 4-NP in drinking water impaired the reproductive ability of Japanese quails, and led to pathological lesions in the male gonads.

Simultaneous analysis 26 mineral element contents from highly consumed cultured chicken overexposed to arsenic trioxide by inductively coupled plasma mass spectrometry

This study assessed the impacts of dietary arsenic trioxide (As₂O₃) on 26 mineral element contents in the liver and kidney of chicken. A total of 100 male Hy-line cocks were randomly divided into 2 groups (50 chickens in each group), including an arsenic-treated group (basic diet supplemented with As₂O₃ at 30 mg/kg) and a control group (basal diet). The feeding experiment lasted for 90 days and the experimental animals were given free access to feed and water. We determined 26 mineral elements in the liver and kidney by inductively coupled plasma mass spectrometry (ICP-MS). The results showed that nine element levels (Al, Mn, Co, Cu, Zn, Se, Cd, Ba, and Pb) were significantly decreased (P < 0.05) in the liver of chickens exposed to As₂O₃ compared to the control chickens where three element levels (Ni, As, and Hg) increased significantly (P < 0.05). The results in the kidney showed that nine element levels (Al, K, Ca, Cr, Mn, Ni, Sb, Ba, and Pb) were significantly decreased (P < 0.05) in the chickens exposed to As₂O₃ compared to the control chickens where four element levels (Mo, As, Cd, and Hg) increased significantly (P < 0.05). These results suggest that supplementation of high levels of arsenic affected trace mineral levels in the liver and kidney of chicken, and the effects vary from organ to organ. The aim of this study is to provide references for further study of heavy metal poisoning by detecting the contents of minerals induced by arsenic in chicken.

Arsenic and dichlorvos: Possible interaction between two environmental contaminants

Metals are ubiquitously present in the environment and pesticides are widely used throughout the world. Environmental and occupational exposure to metal along with pesticide is an area of great concern to both the public and regulatory authorities. Our major concern is that combination of these toxicant present in environment may elicit toxicity either due to additive or synergistic interactions or 'joint toxic actions' among these toxicants. It poses a rising threat to human health. Water contamination particularly ground water contamination with arsenic is a serious problem in today's scenario since arsenic is associated with several kinds of health problems, such arsenic associated health anomalies are commonly called as 'Arsenism'. Uncontrolled use and spillage of pesticides into the environment has resulted in alarming situation. Moreover serious concerns are being addressed due to their persistence in the environmental matrices such as air, soil and surface water runoff resulting in continuous exposure of these harmful chemicals to human beings and animals. Bio-availability of these environmental toxicants has been enhanced much due to anthropological activities. Dreadfully very few studies are available on combined exposures to these toxicants on the animal or human system. Studies on the acute and chronic exposure to arsenic and DDVP are well reported and well defined. Arsenic is a common global ground water contaminant while dichlorvos is one of the most commonly and widely employed organophosphate based insecticide used in agriculture, horticulture etc. There is thus a real situation where a human may get exposed to these toxicants while working in a field. This review highlights the individual and combined exposure to arsenic and dichlorvos on health.

A minireview on N-acetylcysteine: An old drug with new approaches

N-acetylcysteine (NAC), a cysteine pro-drug and glutathione precursor has been used in therapeutic practices for several decades, as a mucolytic agent and for the treatment of numerous disorders including paracetamol intoxication. There is a growing interest concerning the beneficial effects of NAC against the early stages of toxicity-induced by pesticides. Nevertheless, the mechanisms underlying the therapeutic and clinical applications of NAC are not fully understood. In this review we aimed to focus on the protective effects of NAC against oxidative stress caused by pesticide in many organs. The possible mechanisms of action may be associated to its antioxidant properties. The anti-oxidative activity of NAC has been attributed to the fast reaction with free radicals as well as the restitution of reduced glutathione (GSH).

Evaluated the Twenty-Six Elements in the Pectoral Muscle of As-Treated Chicken by Inductively Coupled Plasma Mass Spectrometry

This study assessed the impacts of dietary arsenic trioxide on the contents of 26 elements in the pectoral muscle of chicken. A total of 100 Hy-line laying cocks were randomly divided into two groups (n = 50), including an As-treated group (basic diet supplemented with arsenic trioxide at 30 mg/kg) and a control group (basal diet). The feeding experiment lasted for 90 days and the experimental animals were given free access to feed and drinking water. The elements lithium (Li), boron (B), natrum (Na), magnesium (Mg), aluminium (AI), silicium (Si), kalium (K), calcium (Ca), vanadium (V), chromium (Cr), manganese (Mn), ferrum (Fe), cobalt (Co.), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), molybdenum (Mo), cadmium (Cd), stannum (Sn), stibium (Sb), barium (Ba), hydrargyrum (Hg), thallium (Tl) and plumbum (Pb) in the pectoral muscles were determined using inductively coupled plasma mass spectrometry (ICP-MS). The resulted data indicated that Li, Na, AI, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sn, Ba, Tl and Pb were significantly increased (P < 0.05) in chicken exposed to As2O3 compared to control chicken, while Mg, Si, K, As and Cd decreased significantly (P < 0.05). These results suggest that ICP-MS determination of elements in chicken tissues enables a rapid analysis with good precision and accuracy. Supplementation of high levels of As affected levels of 20 elements (Li, Na, AI, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sn, Ba, Tl, Pb, Mg, Si, K, As and Cd) in the pectoral muscles of chicken. Thus, it is needful to monitor the concentration of toxic metal (As) in chicken for human health.

Alpha-lipoic acid protects oxidative stress, changes in cholinergic system and tissue histopathology during co-exposure to arsenic-dichlorvos in rats

We investigated protective efficacy of α-lipoic acid (LA), an antioxidant against arsenic and DDVP co-exposed rats. Biochemical variables suggestive of oxidative stress, neurological dysfunction, and tissue histopathological alterations were determined. Male rats were exposed either to 50 ppm sodium arsenite in drinking water or in combination with DDVP (4 mg/kg, subcutaneously) for 10 weeks. α-Lipoic acid (50mg/kg, pos) was also co-administered in above groups. Arsenic exposure led to significant oxidative stress along, hepatotoxicity, hematotoxicity and altered brain biogenic amines levels accompanied by increased arsenic accumulation in blood and tissues. These altered biochemical variables were supported by histopathological examinations leading to oxidative stress and cell death. These biochemical alterations were significantly restored by co-administration of α-lipoic acid with arsenic and DDVP alone and concomitantly. The results indicate that arsenic and DDVP induced oxidative stress and cholinergic dysfunction can be significantly protected by the supplementation of α-lipoic acid.

Combined exposure of Japanese quails to cyanotoxins, Newcastle virus and lead: oxidative stress responses

Wild birds are continually exposed to many anthropogenic and natural stressors in their habitats. Over the last decades, mass mortalities of wild birds constitute a serious problem and may possibly have more causations such as natural toxins including cyanotoxins, parasitic diseases, industrial chemicals and other anthropogenic contaminants. This study brings new knowledge on the effects of controlled exposure to multiple stressors in birds. The aim was to test the hypothesis that influence of cyanobacterial biomass, lead and antigenic load may combine to enhance the effects on birds, including modulation of antioxidative and detoxification responses. Eight treatment groups of model species Japanese quail (Coturnix coturnix japonica) were exposed to various combinations of these stressors. The parameters of detoxification and oxidative stress were studied in liver and heart after 30 days of exposure. The antioxidative enzymatic defense in birds seems to be activated quite efficiently, which was documented by the elevated levels and activities of antioxidative and detoxification compounds and by the low incidence of damage to lipid membranes. The greatest modulations of glutathione level and activities of glutathione-S-transferase, glutathione peroxidase, glutathione reductase, superoxide dismutase, catalase and lipid peroxidation were shown mostly in the groups with combined multiple exposures. The results indicate that the antioxidative system plays an important role in the protective response of the tissues to applied stressors and that its greater induction helps to protect the birds from more serious damage. Most significant changes of these "defense" parameters in case of multiple stressors suggest activation of this universal mechanism in situation with complex exposure and its crucial role in protection of the bird health in the environment.

Monocrotophos induced apoptosis in PC12 cells: role of xenobiotic metabolizing cytochrome P450s

Monocrotophos (MCP) is a widely used organophosphate (OP) pesticide. We studied apoptotic changes and their correlation with expression of selected cytochrome P450s (CYPs) in PC12 cells exposed to MCP. A significant induction in reactive oxygen species (ROS) and decrease in glutathione (GSH) levels were observed in cells exposed to MCP. Following the exposure of PC12 cells to MCP (10⁻⁵ M), the levels of protein and mRNA expressions of caspase-3/9, Bax, Bcl₂, P⁵³, P²¹, GSTP1-1 were significantly upregulated, whereas the levels of Bclw, Mcl1 were downregulated. A significant induction in the expression of CYP1A1/1A2, 2B1/2B2, 2E1 was also observed in PC12 cells exposed to MCP (10⁻⁵ M), whereas induction of CYPs was insignificant in cells exposed to 10⁻⁶ M concentration of MCP. We believe that this is the first report showing altered expressions of selected CYPs in MCP-induced apoptosis in PC12 cells. These apoptotic changes were mitochondria mediated and regulated by caspase cascade. Our data confirm the involvement of specific CYPs in MCP-induced apoptosis in PC12 cells and also identifies possible cellular and molecular mechanisms of organophosphate pesticide-induced apoptosis in neuronal cells.