Naringenin suppresses aluminum-induced experimental hepato-nephrotoxicity in mice through modulation of oxidative stress and inflammation

Aluminum is a widely used metal substance in daily life activities that has been shown to cause severe hepato-nephrotoxicity with long-term exposure. Natural dietary flavonoids are being utilized as a newer pharmaceutical approach against various acute and chronic diseases. Naringenin (NAR) has shown efficient therapeutic properties, including effects against metal toxicities. However, the protective efficacy of NAR on aluminum chloride (AlCl3)-induced hepato-renal toxicity needs investigation as aluminum has shown serious environmental toxicity and bioaccumulation behavior. In this study, mice were treated with AlCl3 (10 mg/kg b.w./day) to assess toxicities, and a group of mice were co-treated with NAR (10 mg/kg b.w./day) to assess the protective effects of NAR against hepato-nephrotoxicity. The levels of blood serum enzymes, oxidative stress biomarkers, inflammatory cytokines, and the apoptosis marker caspase-3 were measured using histological examinations. NAR treatment in AlCl3-treated mice resulted in maintained levels of liver and kidney function enzymes and lipid profiles. NAR treatment attenuated oxidative stress by regulating the levels of nitric oxide, advance oxidation of protein products, protein carbonylation, and lipid peroxidation. NAR also replenished reduced antioxidant enzymes such as superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and reduced the levels of glutathione and oxidized glutathione. NAR regulated the levels of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α) and elevated the levels of anti-inflammatory cytokines (IL-4, IL-10, and IFN-γ). The histological study further confirmed the protective effects of NAR against AlCl3-induced hepato-renal alterations. NAR decreased the expression of caspase-3 as a mechanism of protective effects against apoptotic damage in the liver and kidney of AlCl3-treated mice. In summary, this study demonstrated the antioxidant and anti-inflammatory properties of NAR, leading to the suppression of AlCl3-triggered hepato-renal apoptosis and histological alterations. The results suggest that aluminum toxicity needs to be monitored in daily life usage, and supplementation of the natural dietary flavonoid naringenin may help maintain liver and kidney health.

Nephroprotective Effects of Caffeine, Vanillin, and Their Combination against Experimental AlCl3-Induced Renal Toxicity in Adult Male Wistar Rats

Aluminum (Al) is known to be a nephrotoxic metal that can cause renal toxicity in both humans and animals. The use of functional foods has been reported to have significance in managing the toxic effects associated with such metals. This study aimed to assess the potential protective effects of caffeine, vanillin, and their combination in mitigating AlCl3-induced renal toxicity in adult male Wistar rats. A total of thirty (30) adult male Wistar rats weighing between 150 and 200 g were randomly divided into five groups, each consisting of six rats (n = 6). Group 1 served as the control, while the remaining treatment groups received a daily oral dose of 100 mg/kg AlCl3 for a duration of 21 days. In addition, groups 3-5 were coadministered 50 mg/kg body weight (bw) of caffeine, vanillin, and a combination (50/50 mg/kg bw) of both substances, respectively. In the results, AlCl3-treated showed a significant (p < 0.05) increase in serum biomarkers such as ALT, ALP, urea, and creatinine, and a significant (p < 0.05) decrease in serum total proteins (TPs). The renal tissue's antioxidant system, including SOD, CAT, GPx, and GSH, exhibited a significant (p < 0.05) reduction, accompanied by an elevated MDA level. However, the administration of caffeine, vanillin, and their combination resulted in a significant (p < 0.05) decrease in serum ALT, ALP, urea, and creatinine, and a significant (p < 0.05) increase in serum TP. Furthermore, following the treatment, there was a significant (p < 0.05) increase in renal SOD, CAT, GPx, and GSH levels, along with a reduction in the MDA level. In addition, the treatment for 21 days caused a significant (p < 0.05) reversal to the altered histomorphological architecture. These findings suggest that caffeine, vanillin, and their combination could potentially be an effective regimen in managing AlCl3-induced renal toxicity.

Associations of circulating multiple metals with the risk of incident hyperuricemia and the average annual change in uric acid levels

BACKGROUND

Hyperuricemia has been linked to exposure to certain metals in cross-sectional studies. However, prospective studies evaluating the associations of multiple metal exposures with incident hyperuricemia are scarce.

OBJECTIVES

To prospectively investigate the associations of multiple metal/metalloid concentrations with incident hyperuricemia as well as average annual change in uric acid levels in a longitudinal cohort.

METHODS

A longitudinal cohort study included 3957 subjects who were free of cardiovascular disease with certain risk factors for cardiovascular disease at baseline. Incident hyperuricemia was ascertained if serum uric acid level was ≥ 420 μmol/L for men and ≥ 360 μmol/L for women during the follow-up visit in 2013. The relationships between 17 single plasma metals/metalloids and incident hyperuricemia were assessed using unconditional logistic regression models. For metals/metalloids significantly related to incident hyperuricemia, we further utilized generalized linear regression models to evaluate their associations with the average annual change in uric acid levels. Finally, we applied the weighted quantile sum (WQS) regression to investigate the joint effects of metals/metalloids on hyperuricemia risk and uric acid changes, and to identify the most significant metals.

RESULTS

After adjusting for potential confounders, plasma aluminum, arsenic, barium, lead, strontium, vanadium, and zinc concentrations were positively associated with incident hyperuricemia in both main analyses and sensitivity analyzes. Compared to the lowest quartiles, participants in the highest quartiles had 63 %-125 % higher risks of incident hyperuricemia (all FDR < 0.05). Furthermore, the positive associations of these seven metals with an average annual uric acid increase reinforced the findings. Finally, the WQS analyses showed that plasma metals mixtures were positively associated with the risk of incident hyperuricemia (OR: 1.47; 95 % CI: 1.23, 1.76) and the average annual change in uric acid levels (β: 3.17; 95 % CI: 2.42, 3.93), and strontium and vanadium were the most heavily weighted metals, respectively.

CONCLUSION

Our findings identify aluminum, arsenic, barium, lead, strontium, vanadium, and zinc exposures as independent risk factors for hyperuricemia and provide new insights into the prevention of hyperuricemia.

Chitosan oligosaccharide alleviates and removes the toxicological effects of organophosphorus pesticide chlorpyrifos residues

The abuse of chlorpyrifos (CHP), a commonly used organophosphorus pesticide, has caused many environmental pollution problems, especially its toxicological effects on non-target organisms. First, CHP enriched on the surface of plants enters ecosystem circulation along the food chain. Second, direct inflow of CHP into the water environment under the action of rainwater runoff inevitably causes toxicity to non-target organisms. Therefore, we used rats as a model to establish a CHP exposure toxicity model and studied the effects of CHP in rats. In addition, to alleviate and remove the injuries caused by residual chlorpyrifos in vivo, we explored the alleviation effect of chitosan oligosaccharide (COS) on CHP toxicity in rats by exploiting its high water solubility and natural biological activity. The results showed that CHP can induce the toxicological effects of intestinal antioxidant changes, inflammation, apoptosis, intestinal barrier damage, and metabolic dysfunction in rats, and COS has excellent removal and mitigation effects on the toxic damage caused by residual CHP in the environment. In summary, COS showed significant biological effects in removing and mitigating blood biochemistry, antioxidants, inflammation, apoptosis, gut barrier structure, and metabolic function changes induced by residual CHP in the environment.

Aluminum neurotoxicity and autophagy: a mechanistic view

It is strongly believed that aluminum is one of the insalubrious agents because of its neurotoxicity effects and influences on amyloid β (Aβ) production and tau protein hyperphosphorylation following oxidative stress, as one of the initial events in neurotoxicity. The autophagy process plays a considerable role in neurons in preserving intracellular homeostasis and recycling organelles and proteins, especially Aβ and soluble tau. Thus, autophagy is suggested to ameliorate aluminum neurotoxicity effects, and dysfunction of this process can lead to an increase in detrimental proteins. However, the relationship between aluminum neurotoxicity and autophagy dysregulation in some dimensions remains unclear. In the present review, we want to give an overview of the autophagy roles in aluminum neurotoxicity and how dysregulation of autophagy can affect aluminum neurotoxicity.

Hematologic evaluation of peripheral blood in Sprague Dawley rats by chronic exposure to aluminum chloride (AlCl3)

This study aimed to evaluate whether aluminum chloride (AlCl3) causes hematological changes in the peripheral blood of Sprague-Dawley (SD) rats. Five groups of female SD rats were intragastrically administered with 4 different concentrations of AlCl3 for 5 days a week for a total of 90 days. The aluminum concentration was determined via graphite furnace atomic absorption spectroscopy. Analysis of serum iron-kinetic profiles, blood cytometry outcomes, and blood smears of the blood samples. Scanning electron microscopy (SEM) and Raman spectroscopy were used to search for structural and ultrastructural changes, respectively. Blood aluminum concentration ranged 12.38-16.24 μg/L with no significant difference between experimental treatments. At the AlCl3 concentration of 40 mg Al/kg bw of rats/day, the mean ferritin value in the serum iron kinetic profile was 29.81±6.1 ng/mL, and this value showed a significant difference between experimental treatments. Blood cytometry revealed that there were 6.45-7.11×106 cells/μL erythrocytes, 8.91-9.32×103 cells/μL leukocytes, and 477.2-736.3×103 cells/μL platelets along with a hemoglobin of 37.38-41.93 g/dL and hematocrit level of 37.38-41.93%; the experimental treatments showed no significant differences. Erythrocyte structural analysis using SEM showed no differences between experimental treatments, whereas ultrastructural evaluation using Raman spectroscopy made it possible to identify the following bands: 741, 1123, 1350, 1578, and 1618 cm-1, which were respectively associated with the following vibrational modes and compounds: vibration of the tryptophan ring, asymmetric C-O-C stretching of glucose, C-H curve of tryptophan, C=C stretching of the heme group, and C-N stretching of the heme group, with no significant differences between experimental treatments. Therefore, AlCl3 administration does not induce ultrastructural changes in the erythrocyte membrane. This study revealed that serum ferritin concentration was the only parameter affected by AlCl3 exposure at 40 mg of Al/kg bw of rats/day.

Aqueous extract of bay leaf (Laurus nobilis) ameliorates testicular toxicity induced by aluminum chloride in rats

Background and Aim

Human exposure to aluminum is inevitable, and one of the most adverse health effects of aluminum is a decrease in male fertility rates. Therefore, this study investigated the ameliorative effects of an aqueous extract from Laurus nobilis-bay leaf (BL) on aluminum chloride (AlCl₃)-induced testicular toxicity in rats.

Materials and Methods

Twenty-four Wistar rats were divided into four groups (n = 6, each group): The control (group 1) received normal saline; Group 2 animals were intraperitoneally administered with 30 mg/kg body weight (BW) AlCl₃; and Groups 3 and 4 were co-administered AlCl₃ with 125 or 250 mg/kg BW of BL extract, respectively, for 21 days. Testes, epididymis, and blood samples were collected. Testicular plasma enzyme activity was measured using a spectrophotometric assay, while concentrations of inflammatory biomarkers were determined using enzyme-linked immunosorbent assay kits.

Results

There was a significant increase (p < 0.05) in testicular enzyme activity in the group treated with AlCl₃. However, there was no significant (p > 0.05) difference in testicular enzyme activity in groups co-administered AlCl₃ and BL extract as compared with that in control. There was a significant (p < 0.05) increase in testicular nitrite concentration in the AlCl₃-treated group, whereas the administration of BL extract significantly (p < 0.05) decreased nitrite concentration in Groups 3 and 4. Furthermore, the administration of BL extracts increased sperm count and improved the morphology of the testes in AlCl₃-treated rats. Flavonoids, phenolic compounds, alkaloids, tannin, glycosides, saponin, anthraquinones, and steroids were identified in BL extract, with alkaloids and glycosides being the most abundant.

Conclusion

Aqueous extract from BL ameliorated the toxic effect of AlCl₃ and exhibited anti-inflammatory properties by inhibiting nitrite production while improving sperm count and morphology in AlCl₃-treated rats. The bioactivity of the extract may be attributed to the presence of a wide range of phytochemicals. Therefore, BL aqueous extract could be a promising source of novel compounds with male fertility-promoting and anti-inflammatory properties.

The price of persistence: Assessing the drivers and health implications of metal levels in indicator carnivores inhabiting an agriculturally fragmented landscape

Patterns and practices of agricultural expansion threaten the persistence of global biodiversity. Wildlife species surviving large-scale land use changes can be exposed to a suite of contaminants that may deleteriously impact their health. There is a paucity of data concerning the ecotoxicological impacts associated with the global palm oil (Elaeis guineensis) industry. We sampled wild Malay civets (Viverra tangalunga) across a patchwork landscape degraded by oil palm agriculture in Sabah, Malaysian Borneo. Using a non-lethal methodology, we quantified the levels of 13 essential and non-essential metals within the hair of this adaptable small carnivore. We robustly assessed the biological and environmental drivers of intrapopulation variation in measured levels. Metal concentrations were associated with civet age, weight, proximity to a tributary, and access to oxbow lakes. In a targeted case study, the hair metal profiles of 16 GPS-collared male civets with differing space use patterns were contrasted. Civets that entered oil palm plantations expressed elevated aluminium, cadmium, and lead, and lower mercury hair concentrations compared to civets that remained exclusively within the forest. Finally, we paired hair metal concentrations with 34 blood-based health markers to evaluate the possible sub-lethal physiological effects associated with varied hair metal levels. Our multi-facetted approach establishes these adaptable carnivores as indicator species within an extensively altered ecosystem, and provides critical and timely evidence for future studies.

The adjuvant aluminum fate - Metabolic tale based on the basics of chemistry and biochemistry

Aluminum is inevitable component of many vaccines. The benefit of the vaccines is undeniable but effects of aluminum toxicity might be underestimated and neglected. In this review, we highlighted the mechanims of aluminum toxicity, which is still in debate. So far, all the papers that disscused the adverse aluminum effects pointed two mechanisms responsible for Al toxicity, direct Al toxicity and aluminum induced cell damage via the oxidative metabolism. According to our knowledge, which is based on basic principles of biochemistry and inorganic chemistry, we suggested that aluminum highly interferes with iron metabolism eventually resulting in iron-mediated cell damage. More importantly, in this paper, we offered easily feasible solutions, in order to avoid aluminum toxicity in the future. We suggest that as it once was, Calcium Phosphate again to be used as the adjuvant or better solution that the vaccine adjuvants should be based on zinc compounds or even better would be non-metal adjuvants, such as microcrystalline tyrosine and monosodium urate. Until an adequate adjuvant is provided, we suggest instant postponement of vaccination with vaccines which use aluminum as the adjuvant until the 12 months of age.

Rhamnus alaternus aqueous extract enhances the capacity of system redox defence and protects hepatocytes against aluminum chloride toxicity in rats

Background

This study was designed to evaluate the protective effects of a Rhamnus alaternus aqueous extract (RAAE) on aluminum chloride-induced hepatotoxicity in rats. A preliminary phytochemical study and antioxidant activity tests of the extract were performed.

Methods

A preliminary phytochemical study and antioxidant activity tests of the extract were performed. For the in vivo study, twenty-four male rats were divided into four groups. The control group (C); the RAAE group treated with 250 mg/kg b.w RAAE; the AlCl3 group, which received 50 mg/kg b.w AlCl3; and the AlCl3/RAAE group that was treated with AlCl3 plus RAAE.

Results

The RAAE contains several phenolic compounds. This plant extract showed a high radical scavenging effect and high antioxidant activity. Administration of AlCl3 resulted in a significant increase in the activities of aspartate aminotransferase and alanine aminotransferase (AST, ALT), alkaline phosphatase (ALP), and lactate dehydrogenase (LDH) and significant decreases in the plasma concentrations of total proteins and albumin. Moreover, AlCl3 induced a hepatic pro-oxidant effect leading to an increase in malonaldehyde (MDA) and carbonyl protein contents, the depletion of the content of reduced glutathione (GSH) and a decrease in the antioxidant enzymatic activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). However, RAAE supplementation with AlCl3 treatment significantly decreased the levels of MDA and carbonyl proteins and markedly restored the activities of the antioxidant enzymes. These results are supported by the improvement in liver tissue restoration.

Conclusions

The Rhamnus alaternus aqueous extract was shown to have effective antioxidant activity owing to its phenolic compounds protecting against AlCl3-induced liver oxidative damage.

Acute Toxic and Genotoxic Effects of Aluminum and Manganese Using In Vitro Models

The objective of this study was to use the same concentrations of aluminum (Al) and manganese (Mn) detected previously in groundwater above those permitted by Brazilian law and assess their cytotoxic and genotoxic effects in hamster ovary cell lines and their mutagenic effects through the Salmonella microsome assay. Chinese hamster ovary (CHO) and CHO-XRS5 cells were treated with different concentrations of Al and Mn (0.2 to 2.0 mg/L and 0.1 to 3.0 mg/L, respectively). The Ames test was used to analyze the concentrations of Al and Mn ranging from 0.025 to 1.0 mg/L and 0.0125 to 1.5 mg/L, respectively. Both metals showed cytotoxic effects on both cell lines and two bacterial strains (TA98 and TA100). The genotoxic effects of the highest concentrations of Al and Mn in cell lines showed nuclear buds, micronuclei, and DNA damage; however, none of the concentrations showed a positive mutagenic response in the Ames test. This is one of the few studies to demonstrate the cytotoxic effects of Al and Mn through the Ames test. In addition, the metals caused genomic instability in cell lines. Therefore, this study may help hasten the review of established regulatory standards for human consumption of groundwater.

Diverse Effect of Vitamin C and N-Acetylcysteine on Aluminum-Induced Eryptosis

PURPOSE

The role of oxidative stress in Aluminum (Al)-induced apoptotic effects has been investigated and suicidal death of erythrocytes, eryptosis, is characterized by cell shrinkage and phosphatidylserine externalization (PSE) at the surface of the erythrocyte cell membrane. Eryptosis is stimulated by an increase in cytosolic Ca2+ concentration and reactive oxygen species (ROS). This ex vivo study was conducted to evaluate the effect of well-known antioxidants including vitamin C (vit C) and N-acetylcysteine (NAC), against Al-induced hemolysis and eryptosis.

METHODS

Isolated erythrocytes from the healthy volunteers were partitioned into various groups (6 replicates/group) and treated by various concentrations of Al (3-100 µM) in the presence and absence of vit C (0.6 mM) and NAC (1 mM). After 24 hours of treatment, hemolysis was determined from hemoglobin levels in the supernatant. Flowcytometric methods were applied to measure PSE, cell shrinkage, Ca2+ content, and ROS abundance using annexin V-binding, forward scatter, Fluo3-fluorescence, and DCFDA dependent fluorescence, respectively. Reduced glutathione (GSH) was measured by the ELISA method.

RESULTS

The results showed that a 24 hours' exposure of the erythrocytes to Al (10-100 µM) significantly increased hemolysis in a dose and Ca2+dependent manner. Al also dramatically decreased forward scatter. The percentage of PSE cells, Fluo3-fluorescence, and DCFDA fluorescence were increased by Al. Furthermore, cotreatment with NAC inhibited the effect of Al on hemolysis, eryptosis, and ROS production. Vit C decreased Al-induced ROS production. However, increased Al-induced eryptosis. There were no significant changes in glutathione after the ALCL3 treatment.

CONCLUSIONS

Al-induced eryptosis and hemolysis through triggering oxidative stress, while NAC could diverse this effect. In contrast, vit C might intensify Al-induced eryptosis at particular doses through a less known mechanism.

Effects of Long-Term Supplementation with Aluminum or Selenium on the Activities of Antioxidant Enzymes in Mouse Brain and Liver

The aim of this study was to investigate the effects of aluminum (Al) or selenium (Se) on the “primary” antioxidant defense system enzymes (superoxide dismutase, catalase, and glutathione reductase) in cells of mouse brain and liver after long-term (8-week) exposure to drinking water supplemented with AlCl3 (50 mg or 100 mg Al/L in drinking water) or Na2SeO3 (0.2 mg or 0.4 mg Se/L in drinking water). Results have shown that a high dose of Se increased the activities of superoxide dismutase and catalase in mouse brain and liver. Exposure to a low dose of Se resulted in an increase in catalase activity in mouse brain, but did not show any statistically significant changes in superoxide dismutase activity in both organs. Meanwhile, the administration of both doses of Al caused no changes in activities of these enzymes in mouse brain and liver. The greatest sensitivity to the effect of Al or Se was exhibited by glutathione reductase. Exposure to both doses of Al or Se resulted in statistically significant increase in glutathione reductase activity in both brain and liver. It was concluded that 8-week exposure to Se caused a statistically significant increase in superoxide dismutase, catalase and glutathione reductase activities in mouse brain and/or liver, however, these changes were dependent on the used dose. The exposure to both Al doses caused a statistically significant increase only in glutathione reductase activity of both organs.

Milk thistle (Silybum Marianum) as an antidote or a protective agent against natural or chemical toxicities: a review

Biological and chemical agents cause dangerous effects on human health via different exposing ways. Recently, herbal medicine is considered as a biological and safe treatment for toxicities. Silybum marianum (milk thistle), belongs to the Asteraceae family, possesses different effects such as hepatoprotective, cardioprotective, neuroprotective, anti-inflammatory and anti-carcinogenic activities. Several studies have demonstrated that this plant has protective properties against toxic agents. Herein, the protective effects of S. marianum and its main component, silymarin, which is the mixture of flavonolignans including silibinin, silydianin and silychristin acts against different biological (mycotoxins, snake venoms, and bacterial toxins) and chemical (metals, fluoride, pesticides, cardiotoxic, neurotoxic, hepatotoxic, and nephrotoxic agents) poisons have been summarized. This review reveals that main protective effects of milk thistle and its components are attributed to radical scavenging, anti-oxidative, chelating, anti-apoptotic properties, and regulating the inflammatory responses.

Genotoxic Effects of Aluminum Chloride and Their Relationship with N-Nitroso-N-Methylurea (NMU)-Induced Breast Cancer in Sprague Dawley Rats

Recently, soluble forms of aluminum for human use or consumption have been determined to be potentially toxic due to their association with hepatic, neurological, hematological, neoplastic, and bone conditions. This study aims to assess the genotoxic effect of aluminum chloride on genomic instability associated with the onset of N-nitroso-N-methylurea (NMU)-induced breast cancer in Sprague Dawley rats. The dietary behavior of the rats was assessed, and the concentration of aluminum in the mammary glands was determined using atomic absorption spectroscopy. Genomic instability was determined in the histological sections of mammary glands stained with hematoxylin and eosin. Moreover, micronucleus in peripheral blood and comet assays were performed. The results of dietary behavior evaluation indicated no significant differences between the experimental treatments. However, aluminum concentration in breast tissues was high in the +2000Al/−NMU treatment. This experimental treatment caused moderate intraductal cell proliferation, lymph node hyperplasia, and serous gland adenoma. Furthermore, micronucleus and comet test results revealed that +2000Al/−NMU led to a genotoxic effect after a 10-day exposure and the damage was more evident after a 15-day exposure. Therefore, in conclusion, genomic instability is present and the experimental conditions assessed are not associated with breast cancer.

Natural Compounds Rosmarinic Acid and Carvacrol Counteract Aluminium-Induced Oxidative Stress

Aluminum accumulation, glutathione (GSH) and malondialdehyde (MDA) concentrations as well as catalase (CAT) and superoxide dismutase (SOD) activities were determined in erythrocytes and brain and liver homogenates of BALB/c mice treated with Al3+ (7.5 mg/kg/day (0.15 LD50) as AlCl3 (37.08 mg/kg/day), whereas HCl (30.41 mg/kg/day) was used as Cl- control, the treatments were performed for 21 days, i.p., in the presence and absence of rosmarinic acid (0.2805 mg/kg/day (0.05 LD50), 21 days, i.g.) or carvacrol (0.0405 mg/kg/day (0.05 LD50), 21 days, i.g.). The treatment with AlCl3 increased GSH concentration in erythrocytes only slightly and had no effect on brain and liver homogenates. Rosmarinic acid and carvacrol strongly increased GSH concentration in erythrocytes but decreased it in brain and liver homogenates. However, AlCl3 treatment led to Al accumulation in mice blood, brain, and liver and induced oxidative stress, assessed based on MDA concentration in the brain and liver. Both rosmarinic acid and carvacrol were able to counteract the negative Al effect by decreasing its accumulation and protecting tissues from lipid peroxidation. AlCl3 treatment increased CAT activity in mice brain and liver homogenates, whereas the administration of either rosmarinic acid or carvacrol alone or in combination with AlCl3 had no significant effect on CAT activity. SOD activity remained unchanged after all the treatments in our study. We propose that natural herbal phenolic compounds rosmarinic acid and carvacrol could be used to protect brain and liver against aluminum induced oxidative stress leading to lipid peroxidation.

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

Glyphosate (GLP), the most widely used and productive pesticide worldwide, which safety and reliability gradually become a social concern. It is important to explore the toxic of GLP on the limitation level by governments on piglets and the potential role of hepatic CAR/PXR and Keap1-Nrf2 pathways in low levels of glyphosate detoxification. Compared with the control group, the production performance and organ index of GLP group showed no significant change. However, the liver GLP residue of 40 mg/kg group was significantly higher than the control group. We also found that the activity of ALP increased linearly and DBIL content increased quadratically. Furthermore, GLP could significantly increase SOD and GSH-Px and decrease T-AOC and CAT activities and significantly increase MDA and H2O2 contents (P < 0.05); however, the genes expression of Keap1/Nrf2 pathway was not affected. Gene expression of CAR/PXR pathway showed that GLP could significantly stimulate the expression of CAR, but it could not affect the expression of phase Ⅰ (CYP1A1, CYP1A2, CYP2E1, CYP2A19, CYP3A29), phase Ⅱ (UGT1A6, GSTA1, GSTA2) detoxification enzymes and transporters (MDR1, MRP2, P-gp). Our study showed that although 10-40 mg/kg GLP would inevitably cause some liver damage and dysfunction, it can self-alleviating the toxic effect of GLP.

Genotoxicity of Aluminum and Aluminum Oxide Nanomaterials in Rats Following Oral Exposure

Due to several gaps remaining in the toxicological evaluation of nanomaterials (NMs), consumers and public health agencies have shown increasing concern for human health protection. In addition to aluminum (Al) microparticles, Al-containing nanomaterials (Al NMs) have been applied by food industry as additives and contact materials. Due to the limited amount of literature on the toxicity of Al NMs, this study aimed to evaluate the in vivo genotoxic potential of Al0 and Al2O3 NMs after acute oral exposure. Male Sprague-Dawley rats were administered three successive gavages at 6, 12.5 and 25 mg/kg bw. A comparison with AlCl3 was done in order to assess the potential effect of dissolution into Al ions. Both DNA strand breaks and oxidative DNA damage were investigated in six organs/tissues (duodenum, liver, kidney, spleen, blood and bone marrow) with the alkaline and the Fpg-modified comet assays. Concomitantly, chromosomal damage was investigated in bone marrow and colon with the micronucleus assay. The comet assay only showed DNA damage with Al2O3 NMs in bone marrow (BM), while AlCl3 induced slight but non-significant oxidative DNA damage in blood. No increase of chromosomal mutations was observed after treatment with the two Al MNs either in the BM or in the colons of rats.

Aluminum in liver cells - the element species matters

Aluminum (Al) can be ingested from food and released from packaging and can reach key organs involved in human metabolism, including the liver via systemic distribution. Recent studies discuss the occurrence of chemically distinct Al-species and their interconversion by contact with biological fluids. These Al species can vary with regard to their intestinal uptake, systemic transport, and therefore could have species-specific effects on different organs and tissues. This work aims to assess the in vitro hepatotoxic hazard potential of three different relevant Al species: soluble AlCl₃ and two nanoparticulate Al species were applied, representing for the first time an investigation of metallic nanoparticles besides to mineral bound γ-Al₂O₃ on hepatic cell lines. To investigate the uptake and toxicological properties of the Al species, we used two different human hepatic cell lines: HepG2 and differentiated HepaRG cells. Cellular uptake was determined by different methods including light microscopy, transmission electron microscopy, side-scatter analysis, and elemental analysis. Oxidative stress, mitochondrial dysfunction, cell death mechanisms, and DNA damage were monitored as cellular parameters. While cellular uptake into hepatic cell lines occurred predominantly in the particle form, only ionic AlCl₃ caused cellular effects. Since it is known, that Al species can convert one into another, and mechanisms including 'trojan-horse'-like uptake can lead to an Al accumulation in the cells. This could result in the slow release of Al ions, for which reason further hazard cannot be excluded. Therefore, individual investigation of the different Al species is necessary to assess the toxicological potential of Al particles.

Hematological and immunological impairment following in-utero and postnatal exposure to aluminum sulfate in female offspring of albino rats

Aim: Aluminum (Al) is a ubiquitous element extensively utilized in many products like food additives, pharmaceuticals, and vaccines, but its hematotoxic and immunotoxic effects are not entirely clarified. The present study explored the developmental hematotoxic and immunotoxic properties of aluminum sulfate (AS) in rats' offspring. Methods: Forty female offspring (10 rats each) were given three incremental AS doses plus a control group, from conception through lactation and after weaning until reached eight weeks old (near adults). Spleen relative weights along with total and differential blood counts were evaluated. Spectroscopic Al levels in spleen and brain were analyzed. Three immunoglobulins (IgG, IgM, and IgE) and two cytokines, interferon-γ and tumor necrosis factor-α, were measured through the ELISA technique. Results: The results revealed a significant relative increase in splenic weights mostly observed in the highest AS dose treated group. Reduction in the total leukocytic count was noticed in the three AS treated groups with relative lymphocytosis. Additionally, a significant decline in RBCs counts and hemoglobin concentrations were recorded. Tumor necrosis factor-α was significantly elevated in the three Al treated groups, while, interferon- γ showed a non-significant reduction compared to the control group. A significant increment in IgG and decline in IgE concentrations with no change in IgM level among groups were observed. Conclusion: Perinatal AS exposure caused mostly non-linear dose-dependent hematotoxicity and immunological impairment especially for the acquired immunity either cellular or humoral. Further studies can examine the immunotoxic effect of Al on male offspring during different stages of immune development.

Silica - A trace geogenic element with emerging nephrotoxic potential

Silica is a trace-geogenic compound with limited-bioavailability. It inflicts health-perils like pulmonary-silicosis and chronic kidney disease (CKD), when available via anthropogenic-disturbances. Amidst silica-imposed pathologies, pulmonary toxicological-mechanisms are well-described, ignoring the renal-pathophysiological mechanisms. Hence, the present-study aimed to elucidate cellular-cum-molecular toxicological-mechanisms underlying silica-induced renal-pathology in-vitro. Various toxicity-assessments were used to study effects of silica on the physiological-functions of HK-cells (human-kidney proximal-tubular cells - the toxin's prime target) on chronic (1-7 days) sub-toxic (80 mg/L) and toxic (100-120 mg/L) dosing. Results depicted that silica triggered dose-cum-time dependent cytotoxicity/cell-death (MTT-assay) that significantly increased on long-term dosing with ≥100 mg/L silica; establishing the nephrotoxic-potential of this dose. Contrarily, insignificant cell-death on sub-toxic (80 mg/L) dosing was attributed to rapid intracellular toxin-clearance at lower-doses preventing toxic-effects. The proximal-tubular (HK-cells) cytotoxicity was found to be primarily mediated by silica-triggered incessant oxidative-stress (elevated ROS).·This enhanced ROS inflicted severe inflammation and subsequent fibrosis, evident from increased pro-inflammatory-cum-fibrogenic cytokines generation (IL-1β, IL-2, IL-6, TNF-α and TGF-β). Simultaneously, ROS induced persistent DNA-damage (Comet-assay) that stimulated G2/M arrest for p53-mediated damage-repair, aided by checkpoint-promoter (Chk1) activation and mitotic-inducers (i.e. Cdc-25, Cdk1, cyclinB1) inhibition. However, DNA-injuries surpassed the cellular-repair, which provoked the p53-gene to induce mitochondrial-mediated apoptotic cell-death via activation of Bax, cytochrome-c and caspase-cascade (9/3). This persistent apoptotic cell-death and simultaneous incessant inflammation culminated in the development of tubular-atrophy and fibrosis, the major pathological-manifestations of CKD. These findings provided novel-insights into the pathological-mechanisms (cellular and molecular) of silica-induced CKD, inflicted on chronic toxic-dosing (≥100 mg/L).Thereby, encouraging the development of therapeutic-strategies (e.g. anti-oxidant treatment) for specific molecular-targets (e.g. ROS) to retard silica-induced CKD-progression, for reduction in the global-CKD burden.

Aluminum: A potentially toxic metal with dose-dependent effects on cardiac bioaccumulation, mineral distribution, DNA oxidation and microstructural remodeling

Large amounts of aluminum (Al) are found in wastewater from industrial bauxite mining, which is often responsible for the contamination of drinking water sources in urban and rural communities. Although this metal exhibits broad environmental distribution, its cardiac repercussions are poorly understood, making it difficult to establish diagnostic criteria in cases of Al intoxication. In the absence of clinical data, we used a preclinical model to investigate the impact of Al exposure on heart bioaccumulation, molecular oxidation, micromineral distribution, structural and ultrastructural remodeling of the cardiac tissue. Male Wistar rats were equally randomized into five groups: G1 = distilled water; and G2 to G5 = 0.02, 0.1, 50, and 200 mg/kg aluminum solution, respectively. After 120 days, the hearts were collected and subjected to mineral microanalysis, immunoenzymatic detection of 8-OHdG, as well as bright field, polarizing, scanning and transmission electron microscopy to estimate the extent of the cardiac remodeling and cardiomyocytes ultrastructure. Long-term Al exposure induced dose-dependent bioaccumulation, micromineral imbalance, genomic DNA oxidation, structural and ultrastructural abnormalities of the cardiac tissue, resulting in extensive parenchymal loss, stromal expansion, diffuse inflammatory infiltrate, increased glycoconjugate and collagen deposition, subversion and collapse of the collagen network, reduced myocardial vascularization index, mitochondrial swelling, sarcomere disorganization, myofilament dissociation, and fragmentation in cardiomyocytes. Our findings indicated that the heart was sensitive to Al-mediated toxicity, especially in animals treated with the three highest doses of Al. In response to Al-induced loss of the parenchyma, heart stroma exhibited a reactive and compensatory expansion, which, in combination with the increased distribution of thick myofibrils and degenerated mitochondria in cardiomyocytes, provides morphological evidence that cardiac tissue adaptations are not enough to adjust the relationships between the parenchyma and stroma until a steady state is reached, resulting in continuous pathological remodeling potentially associated with Al-induced proinflammatory and pro-oxidant events.

Transgenic zebrafish model for quantification and visualization of tissue toxicity caused by alloying elements in newly developed biodegradable metal

The cytotoxicity of alloying elements in newly developed biodegradable metals can be assessed through relatively low-cost and rapid in vitro studies using different cell types. However, such approaches have limitations; as such, additional investigations in small mammalian models are required that recapitulate the physiological environment. In this study, we established a zebrafish (Danio rerio) model for cytotoxicity evaluations that combines the physiological aspects of an animal model with the speed and simplicity of a cell-based assay. The model was used to assess the cytotoxicity of five common alloying elements in biodegradable implant materials. Conventional in vitro testing using heart, liver, and endothelial cell lines performed in parallel with zebrafish studies revealed statistically significant differences in toxicity (up to 100-fold), along with distinct changes in the morphology of the heart, liver, and blood vessels that were undetectable in cell cultures. These results indicate that our zebrafish model is a useful alternative to mammalian systems for accurately and rapidly evaluating the in vivo toxicity of newly developed metallic materials.

Effect of aluminum chloride on blood glucose level and lipid profile in normal, diabetic and treated diabetic rats

OBJECTIVES

The objectives of the study were to assess evaluate the effects of aluminum chloride (AlCl₃) on blood glucose and lipid levels in normal, diabetic, and glibenclamide-treated diabetic rats.

MATERIALS AND METHODS

Forty-two male Wistar rats were divided into seven groups of six each. Group I was normal control, Groups II and III were given AlCl₃50 and 100 mg/kg, and Group IV to VII were administered with streptozotocin (STZ) (60 mg/kg) intraperitoneally. Group IV was diabetic control, Group V in addition was given AlCl₃50 mg/kg, Group VI glibenclamide (10 mg/kg), and Group VII glibenclamide and AlCl₃(50 mg/kg) per-oral daily for 28 days. Blood glucose and lipid levels were estimated at base line, after diabetes was set in and on the last day of study. Histopathological changes in pancreas, liver, and kidney were studied.

RESULTS

No significant change was observed in blood glucose and lipid levels in Group I. Group II and III showed a dose-dependent significant increase in blood glucose was observed. Group V had a reduction in blood glucose but not to the nondiabetic level. Group VI had significant reduction in blood sugar. In Group VII, treated with glibenclamide and AlCl₃, there was no significant change in blood glucose reduction compared to Group VI. Lipid levels were reduced in groups treated with AlCl₃ and glibenclamide and not in other groups. Gross tissue damage was seen in pancreas in STZ group and in liver and kidney in AlCl₃ groups.

CONCLUSION

AlCl₃ administration in Wistar rats caused in significant hyperglycemia in normal rats, hypoglycemia in diabetic rats, and did not influenced hypoglycemic effect of glibenclamide and in addition, resulted in reduction in lipid levels.

Re-evaluation of aluminium sulphates (E 520-523) and sodium aluminium phosphate (E 541) as food additives

The Panel on Food Additives and Nutrient Sources added to Food (ANS) provided a scientific opinion re‐evaluating the safety of aluminium sulphates (E 520–523) and sodium aluminium phosphate, acidic (E 541) as food additives. The Panel considered that adequate exposure and toxicity data were available. Aluminium sulphates (E 520–523) and sodium aluminium phosphate, acidic (E 541) are permitted as food additives in only a few specific products and the exposure is probably near zero. Aluminium compounds have low bioavailability and low acute toxicity. There is no concern with respect to genotoxicity and carcinogenicity. The no observed adverse effect level (NOAEL) for aluminium compounds in subchronic studies was 52 mg Al/kg body weight (bw) per day in rats and 90 mg Al/kg bw per day in dogs and the lowest NOAEL for neurotoxicity in rats was 30 mg Al/kg bw per day and for developing nervous system was 10–42 mg Al/kg bw per day in studies in mice and rats. The Panel concluded that aluminium sulphates (E 520–523) and sodium aluminium phosphate, acidic (E 541) are of no safety concern in the current authorised uses and use levels.

Ion Imbalance Is Involved in the Mechanisms of Liver Oxidative Damage in Rats Exposed to Glyphosate

Glyphosate (N-phosphonomethyl-glycine, GLP) is the most popular herbicide used worldwide. This study aimed to investigate the effects of glyphosate on rats' liver function and induction of pathological changes in ion levels and oxidative stress in hepatic tissue. Sprague-Dawley rats were treated orally with 0, 5, 50, and 500 mg/kg body weight of the GLP. After 5 weeks of treatment, blood and liver samples were analyzed for biochemical and histomorphological parameters. The various mineral elements content in the organs of the rats were also measured. Significant decreases were shown in the weights of body, liver, kidney and spleen between the control and treatment groups. Changes also happened in the histomorphology of the liver and kidney tissue of GLP-treated rats. The GLP resulted in an elevated level of glutamic-oxalacetic transaminase (GOT), glutamic-pyruvic transaminase (GPT) and IL-1β in the serum. Besides, decreased total superoxide dismutase (T-SOD) activity and increased malondialdehyde (MDA) contents in the serum, liver, and kidney indicated the presence of oxidative stress. Moreover, increase of hydrogen peroxide (H₂O₂) level and catalase (CAT) activity in the serum and liver and decrease of glutathione (GSH) and lutathione peroxidase (GSH-Px) activity in the kidney tissue further confirmed the occurrence of oxidative stress. The results of RT-PCR showed that the mRNA expressions of IL-1α, IL-1β, IL-6, MAPK3, NF-κB, SIRT1, TNF-α, Keap1, GPX2, and Caspase-3 were significantly increased in the GLP-treated groups compared to the control group. Furthermore, PPARα, DGAT, SREBP1c, and SCD1 mRNA expressions were also remarkably increased in the GLP-treated groups compared to the control group. In addition, aluminum (Al), iron (Fe), copper (Cu), zinc (Zn), and magnesium (Mg) levels were showed a significant difference reduction or increase in rat liver, kidney, spleen, lung, heart, muscle, brain, and fat tissues. These results suggested that glyphosate caused obvious damage to rats' liver and caused various mineral elements content imbalances in various organs of rats. Ion imbalance could weaken antioxidant capacity and involve in the mechanism of liver oxidative damage caused by GLP.

Exogenous phosphatidylcholine supplementation retrieve aluminum-induced toxicity in male albino rats

This study investigated the ameliorative potential of exogenous phosphatidylcholine (PC) against aluminum-induced toxicity in male albino rats. Four groups of rats were used for this study (N = 8): group I served as the control, group II (PC treated) received L-α-phosphatidylcholine (egg yolk-derived) 100 mg/kg bwt/day orally, group III (aluminum treated) received aluminum chloride 100 mg/kg bwt/day orally, and group VI (aluminum + PC treated) received similar oral dose of aluminum and PC (100 mg/kg bwt/day). Treatment was continued for 8 weeks. Results revealed that aluminum chloride treatment leading to a significant elevation in serum aspartate aminotransferase, serum alanine aminotransferase, urea, creatinine, malondialdehyde, serum cytokines (tumor necrosis factor-α, interleukin-6), and brain content of acetylcholine, as well as a significant reduction in serum-reduced glutathione, serum testosterone, and brain content of acetylcholinesterase. Moreover, aluminum administration caused significant histopathological alteration in liver, kidney, brain, testes, and epididymis. Co-treatment with exogenous PC resulted in significant improvement in intensity of histopathologic lesions, serum parameters, testosterone level, proinflammatory cytokines, and oxidative/antioxidative status. However, it does not affect the brain content of acetylcholine and acetylcholinesterase. Conclusively, treatment with exogenous PC can retrieve the adverse effect of aluminum toxicities through its antioxidative and anti-inflammatory properties.

The Toxicity of Aluminum Chloride on Kidney of Rats

This study investigated the toxicity of aluminum chloride (AlCl3) exposure in the rat kidney. Forty male Wistar rats (5 weeks old), weighing 110-120 g, were randomly divided into four groups: control group (CG, 0 g/L AlCl3), low dose group (LG, 0.4 g/L AlCl3), mid dose group (MG, 0.8 g/L AlCl3), and high dose group (HG, 1.6 g/L AlCl3). Rats were administered AlCl3 in their drinking water for 120 days. A variety of measurements were taken including superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) activities, malondialdehyde (MDA) concentration in the kidney and blood urea nitrogen (BUN), and cystatin C (Cys-C) concentrations in the serum. In addition, Al and β2-microglobulin (β2-MG) concentrations and the activity of N-acetyl-β-D-glucosaminidase (NAG) in the urine were determined. The results showed that in the AlCl3-treated groups SOD and GSH-PX activities were decreased, while NAG activity and Al, MDA, BUN, Cys-C, and β2-MG concentrations were increased, compared with the CG. This study indicates that AlCl3 exposure induces oxidative stress and suppresses kidney function.

Metal Ion Imbalance-Related Oxidative Stress Is Involved in the Mechanisms of Liver Injury in a Rat Model of Chronic Aluminum Exposure

The objective of the study is to investigate the effects of chronic aluminum overload on rat liver function and its induction of pathological changes in metal ion levels and oxidative stress in hepatic tissues. Wistar rats were intragastrically administered aluminum gluconate (200 mg Al(3+)/Kg) once a day, 5 days a week, for 20 weeks. HE staining was used to visualize pathological changes in rat liver tissue. A biochemical method was adopted to detect ALT, AST, ALP, and GGT levels, as well as liver SOD activity and blood plasma MDA content. A plasma atomic emission spectrophotometer was used to detect Al, Mn, Fe, Zn, and Cu ion contents in liver tissue. Our results showed obvious vacuolar degeneration, granular degeneration, and spotty necrosis in chronic Al-overload rat hepatocytes. The levels of ALT, AST, ALP, and GGT were significantly increased. Liver SOD activity was significantly decreased, and MDA content was significantly increased. In Al-overload rat liver, Al, Mn, Fe, and Cu contents were significantly increased, and in Al-overload rat serum, Mn, Fe, Zn, and Cu contents were significantly decreased. However, the Al level in Al-overload rat serum was not significantly different from that in control rat serum. These results suggest that chronic aluminum overload causes obvious damage to rat liver and causes imbalances in Al, Mn, Fe, Zn, and Cu levels in rat liver and serum. Metal ion imbalance-related oxidative stress may be involved in the mechanism of chronic liver injury caused by aluminum overload.

Different mechanisms for lead acetate, aluminum and cadmium sulfate in rat corpus cavernosum

INTRODUCTION

Some heavy metals show adverse vascular and neurological effects, however, their effect on erection is underestimated. This study aims to investigate the effect of Pb, Cd and Al on erectile function and their potential mechanism of action in rats.

METHODS

Measurement of intracavernosal pressure/mean arterial pressure (ICP/MAP) changes elicited by electrical stimulation of cavernous nerve in anesthetized rats treated with Pb-acetate, Al-sulfate, or Cd-sulfate acutely, and subacutely for 7 days. Serum creatinine, testosterone, TBARs, GSH levels and metal accumulation in corpus cavernosum were measured.

RESULTS

Pb, Al and Cd significantly reduced ICP/MAP in rats after acute (2,10-2,10 and 1,3 mg/kg respectively) and sub-acute (3, 3, and 1mg/kg/day respectively) treatments. They selectively accumulated in the corpus cavernosum reaching 25.107 ± 2.081 μg/g wet weight for Pb, 1.029 ± 0.193 for Cd, 31.343 ± 1.991 for Al, compared to 7.084 ± 1.517, 0.296 ± 0.067, and 8.86 ± 1.115 as controls respectively. Serum creatinine levels were not altered. Cd and Al significantly reduced testosterone level to 0.483 ± 0.059 and 0.419 ± 0.037 ng/ml respectively compared to 0.927 ± 0.105 ng/ml as control. Aluminum elevated TBARs significantly by 27.843%. The acute anti-erectile action of Pb was blocked by non-selective NOS and GC inhibitors and potassium channel blocker. Lead also masked the potentiatory effect of l-arginine and diazoxide on ICP/MAP. No interaction with muscarinic or nicotinic modulators was observed.

CONCLUSIONS

Pb, Cd and Al show anti-erectile effect independent on renal injury. They don not modulate cholinergic nor ganglionic transmission in corpus cavernosum. Pb may inhibit NO/cGMP/K+channel pathway. The effect of Cd and Al but not Pb seems to be hormonal dependent.

Hesperidin and Silibinin Ameliorate Aluminum-Induced Neurotoxicity: Modulation of Antioxidants and Inflammatory Cytokines Level in Mice Hippocampus

Mounting evidence suggests that long-term aluminum exposure results in severe toxic effects, including neurobehavioral and neurochemical anomalies. The present study was performed to examine the neuroprotective potential of hesperidin and silibinin against aluminum chloride (AlCl3)-induced neurotoxicity in mice. AlCl3 (100 mg/kg/day) was injected daily through oral gavage for 42 days. Concomitantly, hesperidin (50 and 100 mg/kg/day, p.o.) and silibinin (100 and 200 mg/kg/day, p.o.) was administered for 42 days in different groups. The extent of cognitive impairment was assessed by Morris water maze and novel object recognition test on the 43rd day. Neurotoxicity was assessed by measuring oxido-nitrosative stress and proinflammatory cytokines in the hippocampus of mice. Six weeks treatment with AlCl3 caused cognitive impairment as indicated by an increase in the retention latency time and reduction in the percentage of recognition index. AlCl3-treated group showed oxido-nitrosative stress as indicated by increase in the level of lipid peroxidation, nitrite and depleted reduced glutathione, catalase activity in the hippocampus. Moreover, the chronic AlCl3 administration raised the proinflammatory cytokines (interleukin-1β and tumor necrosis factor-α) level and increased acetylcholinesterase activity and reduced the BDNF content in the hippocampus of AlCl3-treated animals. However, chronic treatment with hesperidin and silibinin at higher doses significantly ameliorated the AlCl3-induced cognitive impairment and hippocampal biochemical anomalies. The present study clearly indicated that hesperidin and silibinin exert neuroprotective effects against AlCl3-induced cognitive impairment and neurochemical changes. Amelioration of cognitive impairment may be attributed to the impediment of oxido-nitrosative stress and inflammation in the hippocampus.

Orchiectomy attenuates oxidative stress induced by aluminum in rats

The aim of this work was to study whether the increase in antioxidant defenses associated with orchiectomy may account for the reduced susceptibility to aluminum (Al) in male kidney and also to examine whether the reduced antioxidant defenses are associated with androgen levels in orchiectomized (ORX) rats treated with testosterone propionate (TP). Rats were divided into nine groups, namely, intact males (without treatment, treated with sodium lactate, and treated with Al), sham males, ORX males (without treatment, treated with sodium lactate, treated with TP, treated with Al, and treated with TP and Al). Al groups were chronically treated with aluminum lactate for 12 weeks (0.575 mg Al/100 g of body weight, intraperitoneally, three times per week). We reported that ORX rats treated with Al had significantly less lipid peroxidation and an increased level of reduced glutathione (GSH) and GSH/oxidized glutathione ratio in the kidney when compared with intact and TP-treated ORX rats. The activity of superoxide dismutase, catalase, and glutathione peroxidase in ORX rats was much greater than in intact or TP-administered ORX rats. Castration reduced the glomerular alterations caused by Al as well as the number of necrotic tubular cells and nuclear abnormalities. However, we observed a slight alteration in brush border, dilation of proximal tubules, mononuclear infiltrates, and interstitial fibrosis. Castrated males treated with TP showed that this intervention cancels the protective effect of the ORX. This finding suggests that androgens contribute to the development of renal alterations and proteinuria in rats treated with Al. Our results showed that ORX rats are protected against the induction of oxidative stress by Al, but the morphological damage to the kidney tissue induced by the cation was only reduced. Male intact rats treated with Al had more severe glomerulosclerosis, tubular damage, and proteinuria than ORX rats.

Systematic review of potential health risks posed by pharmaceutical, occupational and consumer exposures to metallic and nanoscale aluminum, aluminum oxides, aluminum hydroxide and its soluble salts

Abstract Aluminum (Al) is a ubiquitous substance encountered both naturally (as the third most abundant element) and intentionally (used in water, foods, pharmaceuticals, and vaccines); it is also present in ambient and occupational airborne particulates. Existing data underscore the importance of Al physical and chemical forms in relation to its uptake, accumulation, and systemic bioavailability. The present review represents a systematic examination of the peer-reviewed literature on the adverse health effects of Al materials published since a previous critical evaluation compiled by Krewski et al. (2007) . Challenges encountered in carrying out the present review reflected the experimental use of different physical and chemical Al forms, different routes of administration, and different target organs in relation to the magnitude, frequency, and duration of exposure. Wide variations in diet can result in Al intakes that are often higher than the World Health Organization provisional tolerable weekly intake (PTWI), which is based on studies with Al citrate. Comparing daily dietary Al exposures on the basis of "total Al"assumes that gastrointestinal bioavailability for all dietary Al forms is equivalent to that for Al citrate, an approach that requires validation. Current occupational exposure limits (OELs) for identical Al substances vary as much as 15-fold. The toxicity of different Al forms depends in large measure on their physical behavior and relative solubility in water. The toxicity of soluble Al forms depends upon the delivered dose of Al(+3) to target tissues. Trivalent Al reacts with water to produce bidentate superoxide coordination spheres [Al(O2)(H2O4)(+2) and Al(H2O)6 (+3)] that after complexation with O2(•-), generate Al superoxides [Al(O2(•))](H2O5)](+2). Semireduced AlO2(•) radicals deplete mitochondrial Fe and promote generation of H2O2, O2 (•-) and OH(•). Thus, it is the Al(+3)-induced formation of oxygen radicals that accounts for the oxidative damage that leads to intrinsic apoptosis. In contrast, the toxicity of the insoluble Al oxides depends primarily on their behavior as particulates. Aluminum has been held responsible for human morbidity and mortality, but there is no consistent and convincing evidence to associate the Al found in food and drinking water at the doses and chemical forms presently consumed by people living in North America and Western Europe with increased risk for Alzheimer's disease (AD). Neither is there clear evidence to show use of Al-containing underarm antiperspirants or cosmetics increases the risk of AD or breast cancer. Metallic Al, its oxides, and common Al salts have not been shown to be either genotoxic or carcinogenic. Aluminum exposures during neonatal and pediatric parenteral nutrition (PN) can impair bone mineralization and delay neurological development. Adverse effects to vaccines with Al adjuvants have occurred; however, recent controlled trials found that the immunologic response to certain vaccines with Al adjuvants was no greater, and in some cases less than, that after identical vaccination without Al adjuvants. The scientific literature on the adverse health effects of Al is extensive. Health risk assessments for Al must take into account individual co-factors (e.g., age, renal function, diet, gastric pH). Conclusions from the current review point to the need for refinement of the PTWI, reduction of Al contamination in PN solutions, justification for routine addition of Al to vaccines, and harmonization of OELs for Al substances.