Hepatoprotective Activity of Vitamin E and Metallothionein in Cadmium-Induced Liver Injury in Ctenopharyngodon idellus

Vitamin E alleviates chlorpyrifos induced glutathione depletion, lipid peroxidation and iron accumulation to inhibit ferroptosis in hepatocytes and mitigate toxicity in zebrafish

Organophosphates, a widely used group of pesticides, can cause severe toxicity in human beings and other non-target organisms. Liver, being the primary site for xenobiotic metabolism, is extremely vulnerable to xenobiotic-induced toxicity. Considering the numerous vital functions performed by the liver, including xenobiotic detoxification, protecting this organ from the ubiquitous pesticides in our food and environment is essential for maintaining homeostasis. In this study, we have investigated the impact of the organophosphate pesticide, Chlorpyrifos (CPF), on zebrafish liver at a concentration (300 μg/L) which is environmentally realistic. We have also demonstrated the role of dietary supplementation of α-tocopherol or Vitamin E (Vit E) (500 mg/kg feed) in mitigating pesticide-induced liver toxicity. Mechanistically, we showed that Vit E resulted in significant elevation of the Nrf2 and its downstream antioxidant enzyme activities and gene expressions, especially that of GST and GPx, resulting in reduction of CPF-induced intracellular lipid ROS and hepatic LPO. Further interrogation, such as analysis of GSH: GSSG ratio, intracellular iron concentration, iron metabolizing genes, mitochondrial dysfunction etc. revealed that CPF induces ferroptosis which can be reversed by Vit E supplementation. Ultimately, reduced concentration of CPF in zebrafish serum and flesh highlighted the role of Vit E in ameliorating CPF toxicity.

Vitamin E: An assistant for black soldier fly to reduce cadmium accumulation and toxicity

Cadmium (Cd) is a toxic heavy metal associated with osteoporosis, liver, and kidney disease. The black soldier fly (BSF) Hermetia illucens may be exposed to Cd during the transformation of livestock manure. The BSF has a high tolerance to Cd. In the previous work of the laboratory, we found that vitamin E (VE) may play a role in the tolerance of BSF to Cd exposure. The main findings are as follows: The BSF larvae pretreated with exogenous VE had heavier body weight, lower content and toxicity of Cd under similar Cd exposure. Even in high Cd exposure at the concentrations of 300 and 700 mg/kg, the BSF larvae pretreated with exogenous VE at a concentration of 100 mg/kg still reduced the Cd toxicity to 85.33 % and 84.43 %, respectively. The best-fitting models showed that metallothionein (MT) content, oxidative damage (8-hydroxydeoxyguanosine content, malondialdehyde content), antioxidant power (total antioxidant power, peroxidase activity) had a great influence on content and toxicity of Cd bioaccumulated in the larvae. The degree of oxidative damage was reduced in the larvae with exogenous VE pretreatments. This variation can be explained by their changed MT content and increased antioxidant power because of exogenous VE. These results reveal the roles of VE in insects defense against Cd exposure and provide a new option for the prevention and therapy of damage caused by Cd exposure.

ROS-mediated PERK-CHOP pathway plays an important role in cadmium-induced HepG2 cells apoptosis

Cadmium (Cd) is a common heavy metal that is highly toxic to the liver, however, the exact mechanism underlying this damage accompanied by apoptosis has not been thoroughly demonstrated. In this study, we found that Cd exposure significantly reduced cell viability, including the increased populations of apoptotic cells and caspase-3/-7/-12 activation in HepG2 cells. Mechanistically, Cd initiated oxidative stress via elevating reactive oxygen species (ROS) levels, leading to oxidative damage in HepG2 cells. Simultaneously, Cd exposure induced endoplasmic reticulum (ER) stress via activating the protein kinase RNA-like ER kinase (PERK)-C/EBP homologous protein (CHOP) axis in HepG2 cells, and subsequently disturbed ER function as increased Ca2+ releasing from ER lumen. Intriguingly, further study revealed that oxidative stress is closely related with ER stress, as pretreatment with ROS scavenger, N-acetyl-l-cysteine (NAC) markedly reduced ER stress as well as protected ER function in Cd treated HepG2 cell. Collectively, these findings first revealed Cd exposure induced HepG2 cells death via a ROS-mediated PERK-CHOP-related apoptotic signaling pathway, which provides a novel insight into the mechanisms of Cd-induced hepatotoxicity. Furthermore, inhibitors for oxidative stress and ER stress might be considered as a new strategy to prevent or treat this disorder.

Cadmium induced bioaccumulation, histopathology, gene regulation in fish and its amelioration - A review

Different anthropogenic activities as well as natural sources contribute enormously towards various heavy metal contaminations in aquatic habitats. Cadmium (Cd) is one of most prevalent and toxic heavy metals with a long half life. Unlike terrestrial animals, exposure of Cd in fishes may happen not only through feeds but also from its habitat water. Bioaccumulation of Cd in fishes occurs in many tissues, but mainly in gill, liver, kidney, skin, and muscle. The concentrations of Cd in fish tissues depend upon the extent and duration of Cd exposure, species and age of fishes, dietary minerals and antioxidant concentrations, and habitat water quality. Specific histopathological observations in liver, kidney, and gill are useful to understand the effects of Cd, which could help to determine the ameliorating methods to be adopted. Exposure of Cd exerts several adverse effects on general growth and development, reproductive processes, osmoregulation, morphological and histological structures, stress tolerance, and endocrine system, mainly due to changes in biological functions induced by differential expressions of several genes related to oxidative stress, apoptosis, inflammation, immunosuppressions, genotoxicity, Cd chelation and carbohydrate metabolism. Chronic biomagnifications of Cd exceeding the permitted level may be harmful not only to the fishes itself but also to humans through food chains. Amelioration of such toxic heavy metal that has been categorized as a potent carcinogenic in humans is of utmost importance. Main modes of amelioration encompas reducing oxidative damages by promoting the antioxidative defenses, decreasing Cd absorption, increasing excretion through excretory system and improving the tolerance of fishes to Cd toxicity. Many amelioration measures such as use of minerals (for example, zinc, calcium, and iron), vitamins (vitamin C, A, and E), different herbs, probiotics and other agents (taurine, bentonite, chitosan, zeolite, and metallothionein) have been explored for their effective roles to reduce Cd bioaccumulation and toxicity symptoms in fishes. The present review discusses bioaccumulation of Cd, histopathological alterations, oxidative stress, synergism-antagonism, and gene regulation in different tissues, and its amelioration measures in fishes.

Acute deltamethrin exposure induces oxidative stress, triggers endoplasmic reticulum stress, and impairs hypoxic resistance of crucian carp

Deltamethrin (Del) has been widely used for effectively controlling ectoparasites of crucian carp and was also strictly prohibited in a hypoxic environment. A previous study indicated that Del exposure causes gill injury in Carassius auratus, which is associated with oxidative stress and endoplasmic reticulum stress (ER stress), but the precise mechanism is not well understood. Here, crucian carp were exposed to Del (0.61, 1.22, 2.44, 4.88 μg/L) for 24 h and then subjected to acute hypoxia challenge (1.0 mg/L) for 24 h. The results revealed that acute exposure to Del notably increased MDA content but markedly decreased CAT activities. Moreover, the T-AOC and SOD activities first increased and then decreased in the 4.88 μg/L Del group. Likewise, the mRNA levels of Nrf2 signaling and its target genes (ho-1, mt, sod, cat, and gpx1) were significantly downregulated in the high concentration exposure groups, while the mRNA levels of keap1 showed the opposite change trend. Meanwhile, Del exposure evoked the PERK-ATF4-CHOP and IRE1 signaling pathways and triggered ER stress in a dose-dependent manner in crucian carp. Importantly, we found that Del exposure significantly decreased the survival rate of crucian carp after hypoxia challenge by reducing oxygen uptake, modifying energy metabolism, and promoting lactate accumulation. Additionally, Del exposure aggravated gill damage and apoptosis under hypoxic stress, which was confirmed by histological assays. Collectively, we inferred that acute exposure to deltamethrin induces oxidative stress and ER stress and impairs hypoxic resistance of crucian carp.

Curative Potential of Substances with Bioactive Properties to Alleviate Cd Toxicity: A Review

Rapid urbanization and industrialization have led to alarming cadmium (Cd) pollution. Cd is a toxic heavy metal without any known physiological function in the organism, leading to severe health threat to the population. Cd has a long half-life (10-30 years) and thus it represents serious concern as it to a great extent accumulates in organs or organelles where it often causes irreversible damage. Moreover, Cd contamination might further lead to certain carcinogenic and non-carcinogenic health risks. Therefore, its negative effect on population health has to be minimalized. As Cd is able to enter the body through the air, water, soil, and food chain one possible way to defend and eliminate Cd toxicities is via dietary supplements that aim to eliminate the adverse effects of Cd to the organism. Naturally occurring bioactive compounds in food or medicinal plants with beneficial, mostly antioxidant, anti-inflammatory, anti-aging, or anti-tumorigenesis impact on the organism, have been described to mitigate the negative effect of various contaminants and pollutants, including Cd. This study summarizes the curative effect of recently studied bioactive substances and mineral elements capable to alleviate the negative impact of Cd on various model systems, supposing that not only the Cd-derived health threat can be reduced, but also prevention and control of Cd toxicity and elimination of Cd contamination can be achieved in the future.

The role of well-known antioxidant vitamins in the prevention of cadmium-induced toxicity

Long-term exposure to cadmium (Cd) leads to the development of a number of conditions associated with liver and kidney damage, reproductive and cardiovascular disorders, in addition to visual impairment, blindness and hearing loss, among others. Cadmium has been classified as a human carcinogen by the International Agency for Research on Cancer. The toxicity of Cd is related to its pro-oxidant properties and the associated increase in oxidative stress. Antioxidant ingredients may be helpful in preventing the adverse effects of Cd. The effect of well-known antioxidant vitamins (E, C, A and β-carotene) in the prevention of Cd-induced toxicity is presented in this study. Numerous studies in animal models have shown that the effects of vitamins: E, C, A, and β-carotene were effective in reducing Cd concentrations in organs and tissues and reduced Cd-induced changes in liver, kidney, and reproductive, circulatory, nervous, immune, and respiratory systems. In contrast, the limited number of human studies does not allow to accurately determine the role of these nutrients in reducing Cd-induced toxicity, indicating the need for further studies clarifying the role of antioxidant vitamins in reducing Cd-induced toxicity. However, it seems reasonable to promote the consumption of natural food products that are sources of antioxidant vitamins in groups of people with occupational and environmental exposure to Cd. Int J Occup Med Environ Health. 2022;35(4):367-92.

A Study on the Time-Effect and Dose-Effect Relationships of Polysaccharide from Opuntia dillenii against Cadmium-Induced Liver Injury in Mice

The purpose of this study was to evaluate the protective effect of Opuntia dillenii (Ker-Gaw) Haw. polysaccharide (ODP) against cadmium-induced liver injury. Cadmium chloride (CdCl2) was used to construct a mice evaluation model, and the indicators chosen included general signs, liver index, biochemical indicators, blood indicators, and pathological changes. A dose of 200 mg/kg ODP was applied to the mice exposed to cadmium for different lengths of time (7, 14, 21, 28, and 35 days). The results showed that CdCl2 intervention led to slow weight growth (reduced by 13−20%); liver enlargement; significantly increased aspartate aminotransferase (AST, 45.6−52.0%), alanine aminotransferase (ALT, 26.6−31.3%), and alkaline phosphatase (ALP, 38.2−43.1%) levels; and significantly decreased hemoglobin (HGB, 13.1−15.2%), mean corpuscular hemoglobin (MCH, 16.5−19.3%), and mean corpuscular hemoglobin concentrations (MCHC, 8.0−12.7%) (p < 0.01). In addition, it led to pathological features such as liver cell swelling, nuclear exposure, central venous congestion, apoptosis, and inflammatory cell infiltration. The onset of ODP anti-cadmium-induced liver injury occurred within 7 days after administration, and the efficacy reached the highest level after continuous administration for 14 days, a trend that could continue until 35 days. Different doses (50, 100, 200, 400, and 600 mg/kg) of ODP have a certain degree of protective effect on cadmium-induced liver injury, showing a good dose−effect relationship. After 28 days of administration of a 200 mg/kg dose, all pathological indicators were close to normal values. These findings indicated that ODP had positive activity against cadmium-induced liver injury and excellent potential for use as a health food or therapeutic drug.

Engineered Bacteria EcN-MT Alleviate Liver Injury in Cadmium-Exposed Mice via its Probiotics Characteristics and Expressing of Metallothionein

Cadmium (Cd) exposure is a widespread problem in many parts of the world, but effective means to treat Cd exposure is still lacking. Hence, an engineered strain expressing metallothionein (MT) named Escherichia coli Nissle 1917 (EcN)-MT was constructed, and its potential in the treatment of Cd exposure was evaluated. The in vitro studies showed that metallothionein expressed by EcN-MT could significantly bind Cd. Further, the in vivo results indicated that EcN-MT strain could reduce 26.3% Cd in the liver and increase 24.7% Cd in the feces, which greatly decreased malondialdehyde (MDA) levels and increased catalase (CAT), glutathione (GSH), and superoxide dismutase (SOD) levels in liver, and reduced the expression of toll-like receptor4 (TLR4), nuclear factor-κB (NF-κB), the myeloid differentiation factor 88 (Myd88) andincreased B-cell lymphoma 2 (Bcl-2)/Bcl-2-Associated X (Bax). Moreover, high throughput sequencing results indicated that EcN-MT strain greatly enhanced the beneficial bacteria of Ruminococcaceae, Lactobacillaceae, Akkermansia, Muribaculaceae, Lachnospiraceae, Dubosiella and restored the disturbed microbial ecology to the normal level. Therefore, the high Cd binding capacity of the expressed metallothionein, together with the beneficial characteristics of the host bacteria EcN, makes EcN-MT a sound reagent for the treatment of subchronic Cd exposure-induced liver injury.

Vitamin E protects against cadmium-induced sub-chronic liver injury associated with the inhibition of oxidative stress and activation of Nrf2 pathway

Hepatic oxidative stress, as one important mechanism of cadmium (Cd)-induced hepatic toxicity, could, as known, be ameliorated by vitamin E (VE). However, the underlying mechanism remains to be elucidated. To investigate whether the antioxidant vitamin E can protect against Cd-induced sub-chronic liver injury associated with oxidative stress and nuclear factor erythrocyte 2-related factor 2 (Nrf2) pathway, male Sprague-Dawley rats (nine-week-old) were randomly divided into four groups (eight rats/group), namely, control, VE (100 mg/kg VE), Cd (5 mg/kg CdCl₂) and VE+Cd (100 mg/kg VE+5 mg/kg CdCl₂), and received intragastric administration of Cd and/or VE for four weeks. Cd-exposure alone resulted in reduced liver weight, liver histological alteration and oxidative stress, accumulation of Cd in the liver, elevated ALT and AST concentrations in serum together with decreased mRNA and protein expressions of Nrf2 pathway related molecules (Nrf2, HO-1, NQO-1, GCLC, GCLM and GST). However, the co-treatment of Cd and VE significantly ameliorated the changes mentioned above, and promoted the expression of genes and proteins of Nrf2 pathway related molecules in comparison to the Cd-exposure alone. Our results indicate that the protective effect of VE against Cd-induced sub-chronic hepatic damage in rats is associated with the inhibition of oxidative stress and activation of Nrf2 pathway.

The protective efficacy of vitamin E and cod liver oil against cisplatin-induced acute kidney injury in rats

Cisplatin (CP) is a highly effective chemotherapeutic agent against neoplasms, but its clinical utility is limited due to the side effects of its dose-dependent nephrotoxicity. Vitamin E (Vit E) and cod liver oil (CLO) are natural substances with chemoprotective effects. The present study was conducted to evaluate the protective effects of Vit E and/or CLO for CP-induced acute kidney injury (AKI) in rats. This study involved 40 mature male Wistar albino rats that were equally allocated into eight groups: Veh, Vit E, CLO, Vit E + CLO, CP, Vit E + CP, CLO + CP, and Vit E + CLO + CP. The co-administration of Vit E and CLO significantly ameliorated CP-induced elevations in serum creatinine (Cr), blood urea nitrogen (BUN), interleukin 1 beta (IL-1β), and interleukin- 6 (IL-6). Further, rats that received Vit E and/or CLO showed significant decrease in malondialdehyde (MDA) and increases in superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) levels in renal tissues, compared to CP-intoxicated rats. Additionally, the treatment restored the normal histological architecture (except for few cast formations) and upregulated the immunostaining area% of aquaporin 3 (AQP3) and downregulated the immunostaining area% of Bcl2 associated X protein (BAX) and inducible nitric oxide synthase (iNOS). The observed effects were stronger in the combination treatment group. The obtained data revealed that Vit E and CLO co-administration protects against the CP-induced AKI more than monotherapy with Vit E or CLO.

Efficient Removal of Cd(II) Using SiO2-Mg(OH)2 Nanocomposites Derived from Sepiolite

The pollution of Cadmium (Cd) species in natural water has attracted more and more attention due to its high cumulative toxicity. In the search for improved removal of cadmium from contaminated water, we characterized uptake on a recently identified nanomaterial (SiO₂-Mg(OH)₂) obtained by subjecting sepiolite to acid-base modification. The structural characteristics of SiO₂-Mg(OH)₂ were analyzed by means of SEM-EDS, Fourier Transform Infra-Red Spectroscopy (FTIR) and Powder X-ray Diffraction (PXRD). Static adsorption experiments were carried out to evaluate the effect of contact time, temperature, amount of adsorbent, and pH-value on the adsorption of Cd(II) by SiO₂-Mg(OH)₂. The results show that the pore structure of SiO₂-Mg(OH)₂ is well developed, with specific surface area, pore size and pore volume increased by 60.09%, 16.76%, and 43.59%, respectively, compared to natural sepiolite. After modification, the sepiolite substrate adsorbs Cd(II) following pseudo-second-order kinetics and a Langmuir surface adsorption model, suggesting both chemical and physical adsorption. At 298 K, the maximum saturated adsorption capacity fitted by Sips model of SiO₂-Mg(OH)₂ regarding Cd(II) is 121.23 mg/g. The results show that SiO₂-Mg(OH)₂ nanocomposite has efficient adsorption performance, which is expected to be a remediation agent for heavy metal cadmium polluted wastewater.

Senna alexandrina extract supplementation reverses hepatic oxidative, inflammatory, and apoptotic effects of cadmium chloride administration in rats

Senna alexandrina is traditionally used for its antioxidant and anti-inflammatory properties, but little information is available concerning its potential protective effects against cadmium, which is a widespread environmental toxicant that causes hepatotoxicity. Here, we explored the effects of S. alexandrina extract (SAE) on cadmium chloride (CdCl₂)-induced liver toxicity over 4 weeks in rats. Rats were allocated into four groups: control, SAE (100 mg/kg), CdCl₂ (0.6 mg/kg), and SAE + CdCl₂, respectively. Cadmium level in hepatic tissue, blood transaminases, and total bilirubin as indicators of liver function were assessed. Oxidative stress indices [malondialdehyde (MDA), nitrate/nitrite (NO), and glutathione (GSH)], antioxidant molecules [superoxide dismutase (SOD, catalase (CAT), glutathione-derived enzymes, and nuclear factor erythroid 2-related factor 2 (Nrf2)], pro-inflammatory mediators [interleukin-1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α)], apoptosis proteins (Bcl-2, Bax, and caspase-3), and histological alterations to the liver were examined. SAE administration before CdCl₂ exposure decreased cadmium deposition in liver tissue and the blood liver function indicators. SAE pre-treatment prevented oxidative, inflammatory, and apoptotic reactions and decreased histological alterations to the liver caused by CdCl₂ exposure. SAE can be used as a promising protective agent against CdCl₂-induced hepatotoxicity by increasing Nrf2 expression. Graphical abstract.

Synergistic potential of propolis and vitamin e against sub-acute toxicity of AlCl(3) in albino mice: in vivo study

Current study evaluated the synergistic potential of propolis and vitamin E against sub-acute toxicity of aluminum chloride on different biochemical parameters and liver histology. Swiss albino mice (n=42) were randomly divided into seven groups. Group I received 0.2 ml of 0.9 % saline solution, Group II received Propolis (50 mg/kg b.w.), Group III received vitamin E (150 mg/kg b.w.), Group IV received AlCl(3) 50 mg/kg b.w., Group V received AlCl(3) + Propolis, Group VI received AlCl(3) + vitamin E and Group VII received AlCl(3) + propolis + vitamin E. Blood and tissue samples were collected after 7 and 21 days. The body weight of the animals significantly increased in all groups except Group IV. The concentration of serum high density lipoprotein significantly decreased in Group IV and increased in Group V, VI and VII. The level of aspartate aminotransferase, alanine transferase, alkaline phosphatase, triglycerides, total cholesterol, and low density lipoprotein significantly increased in AlCl(3) treated group and increased in Group V, VI and VII. Tissue sections were processed and stained by hematoxylin and eosin. Group II showed cellular necrosis. Group V, VI showed decreased number of vacuolization, sinusoidal spacing and macrophage cell infiltration. Group VI showed less degenerative changes in the third week. Vitamin E and propolis in combination with Al provides more protection against AlCl(3) induced toxicity.

Metallothionein-I + II Reduces Oxidative Damage and Apoptosis after Traumatic Spinal Cord Injury in Rats

After spinal cord injury (SCI), some self-destructive mechanisms start leading to irreversible neurological deficits. It is known that oxidative stress and apoptosis play a major role in increasing damage after SCI. Metallothioneins I and II (MT) are endogenous peptides with known antioxidant, neuroprotective capacities. Taking advantage of those capacities, we administered exogenous MT to rats after SCI in order to evaluate the protective effects of MT on the production of reactive oxygen species (ROS) and lipid peroxidation (LP), as markers of oxidative stress. The activities of caspases-9 and -3 and the number of annexin V and TUNEL-positive cells in the spinal cord tissue were also measured as markers of apoptosis. Rats were subjected to either sham surgery or SCI and received vehicle or two doses of MT (10 μg per rat) at 2 and 8 h after surgical procedure. The results showed a significant increase in levels of MT protein by effect of SCI and SCI plus treatment at 12 h, while at 24 h an increase of MT was observed only in the injury plus treatment group (p < 0.05). ROS production was decreased by effect of MT in lesioned tissue; likewise, we observed diminished LP levels by MT effect both in the sham group and in the group with SCI. Also, the results showed an increase in the activity of caspase-9 due to SCI, without changes by effect of MT, as compared to the sham group. Caspase-3 activity was increased by SCI, and again, MT treatment reduced this effect only at 24 h after injury. Finally, the results of the number of cells positive to annexin V and TUNEL showed a reduction due to MT treatment both at 24 and 72 h after the injury. With the findings of this work, we conclude that exogenously administered MT has antioxidant and antiapoptotic effects after SCI.

The Effect of Vitamin E and Metallothionein on the Antioxidant Capacities of Cadmium-Damaged Liver in Grass Carp Ctenopharyngodon idellus

Cadmium (Cd) causes a broad spectrum of toxicological effects to animals. Aquatic animals were more likely to accumulate Cd than terrestrial animals because of the living environment. Clearance of Cd in aquatic animals has become an important part of aquatic food safety. The present study was focused on the oxidative damage induced by Cd in the liver of grass carp Ctenopharyngodon idellus and the protective effect of vitamin E (VE) and metallothionein (MT). Grass carp were divided into four groups: the control group, Cd+phosphate-buffered saline (PBS) group, Cd+VE group, and Cd+MT group. All fish were injected with CdCl₂ on the first day and then VE, MT, and PBS were given 4 days after injection, respectively. The liver function and antioxidant capacity of grass carp were evaluated. Cd administration resulted in damage of liver function and morphology in liver, which was expressed as the increased content of AST and ALT, rupture of organelles, and decrease of CAT, SOD, and GSH-Px activity. However, VE and MT treatments protected against Cd-induced damage of liver in grass carp by decreasing AST and ALT content, repairing organelles, and maintained the antioxidant system by elevating CAT, SOD, and GSH-Px activity and regulating related mRNA transcript expression. The results revealed that VE and MT might play an important role in the treatment of heavy metal poisoning through their antioxidative effects.