Metal nanoparticle-induced effects on green toads (Amphibia, Anura) under climate change: conservation implications.

The toxicity of aluminum oxide (Al2O3), copper oxide (CuO), iron oxide (Fe3O4), nickel oxide (NiO), zinc oxide (ZnO), and titanium dioxide (TiO2) nanoparticles (NPs) on amphibians and their interaction with high temperatures, remain unknown. In this study, we investigated the survival, developmental, behavioral, and histological reactions of Bufotes viridis embryos and larvae exposed to different NPs for a duration of 10 days, using lethal concentrations (LC25%, LC50%, and LC75% mg/L) under both ambient (AT: 18 °C) and high (HT: 21 °C) temperatures. Based on LC, NiONPs > ZnONPs > CuONPs > Al2O3NPs > TiO2NPs > Fe3O4NPs showed the highest mortality at AT. A similar pattern was observed at HT, although mortality occurred at lower concentrations and Fe3O4NPs were more toxic than TiO2NPs. The results indicated that increasing concentrations of NPs significantly reduced hatching rates, except for TiO2NPs. Survival rates decreased, abnormality rates increased, and developmental processes slowed down, particularly for NiONPs and ZnONPs, under HT conditions. However, exposure to low concentrations of Fe3O4NPs for up to 7 days, CuONPs for up to 72 h, and NiO, ZnONPs, and TiO2NPs for up to 96 h did not have a negative impact on survival compared with the control group under AT. In behavioral tests with larvae, NPs generally induced hypoactivity at AT and hyperactivity at HT. Histological findings revealed liver and internal gill tissue lesions, and an increase in the number of melanomacrophage centers at HT. These results suggest that global warming may exacerbate the toxicity of metal oxide NPs to amphibians, emphasizing the need for further research and conservation efforts in this context.

Determination of oxidative stress responses caused by aluminum oxide (γ-Al2O3 and α-Al2O3) nanoparticles in Gammarus pulex.

The rapid growth in the use of aluminum oxide nanoparticles (Al2O3 NPs) in various fields such as medicine, pharmacy, cosmetics industries and engineering, and the fact that these NPs and their wastes mix with the aquatic environment and damage the aquatic ecosystem, affect the organisms in the water, enter the food chain and reach humans is a major problem is cause for concern. The aim of this study is to investigate the oxidative stress caused by two separate forms of aluminum oxide, γ-Al2O3 and α-Al2O3, in Gammarus pulex, which is a good indicator species, with biochemical parameters. For this purpose, G. pulex was exposed to different concentrations (0, 10, 20, 40 ppm) of γ-Al2O3 and α-Al2O3 separately. The experiments were carried out for 24 and 96 h by creating 3 repeated experimental groups consisting of 4 groups. For biomarker analysis, superoxide dismutase (SOD), catalase (CAT) activities and glutathione (GSH) and thiobarbituric acid (TBARS) levels were performed using an ELISA kit. As a result of the in experimental study, it was observed that both nanoparticles affected oxidative stress and antioxidant parameters after 96 h compared to the control group. Increases in SOD activity were observed, γ-Al2O3 caused a decrease in CAT activity at 24 h, and α- Al2O3 caused increases in CAT activity at 96 h. Decreases in GSH levels and increases in TBARS levels have been observed.

Environmental aluminum oxide inducing neurodegeneration in human neurovascular unit with immunity.

Aluminum oxide nanoparticle (AlNP), a ubiquitous neurotoxin highly enriched in air pollution, is often produced as an inevitable byproduct in the manufacturing of industrial products such as cosmetics and metal materials. Meanwhile, ALNP has emerged as a significant public health concern due to its potential association with neurological diseases. However, the studies about the neurotoxic effects of AlNP are limited, partially due to the lack of physiologically relevant human neurovascular unit with innate immunity (hNVUI). Here, we employed our AlNP-treated hNVUI model to investigate the underlying mechanism of AlNP-driven neurodegeneration. First, we validated the penetration of AlNP across a blood-brain barrier (BBB) compartment and found AlNP-derived endothelial cellular senescence through the p16 and p53/p21 pathways. Our study showed that BBB-penetrating AlNP promoted reactive astrocytes, which produced a significant level of reactive oxygen species (ROS). The astrocytic neurotoxic factors caused neuronal damage, including the synaptic impairment, the accumulation of phosphoric-tau proteins, and even neuronal death. Our study suggests that AlNP could be a potential environmental risk factor of neurological disorders mediated by neuroinflammation.

Investigation of the Inhibition Activity of Aluminium Oxide Nanoparticles for Herpes Simplex Type 1.

Several studies have shown that Herpes simplex type 1 )HSV-1 (is one of the viruses resistant to medications, so potential antiherpetic agents need to be evaluated. This study aimed to evaluate the impact of Aluminum Oxide Nanoparticles (Al2O3-NPs) on HSV-1 infection. Characterization of Al2O3-NPs was performed using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), dynamic light scattering (DLS), and high-resolution transmission electron microscopy (HRTEM). The MTT test was used to investigate the toxicity action of Al2O3-NPs on viable cells. Quantitative Real-Time PCR (qRT-PCR)and TCID50 assays were used to achieve the antiherpetic performance Al2O3-NPs.Indirect immunofluorescence assay (IFA) was performed to determine the inhibitory impact of Al2O3-NPs on viral antigen expression, and acyclovir was utilized as a standard agent in all tests. HSV-1 subjected to Al2O3-NPs at the maximum non-toxic concentration (100 µg / mL) leads to a decrease of 0.1, 0.7, 1.8, and 2.5 log10 TCID50 in the infectious titer relative to virus control (P<0.0001). This concentration of Al2O3-NPs was correlated with 16.9%, 47.1 %, 61.2 %, 72.5 % and 74.6 % inhibition rates, calculated based on HSV-1 viral load compared to virus control. Our results have shown that Al2O3-NPs have a robust antiviral activity against HSV-1. This function demonstrates excellent potential for using Al2O3-NP in topical formulations for treating orolabial or genital herpetic lesions.

Particle Size Effect of Micro and Nano Aluminium Oxides on Antioxidant Defence System of Model Organism Galleria mellonella.

Studies on heavy metal toxicity show that toxicity of nanoparticles compared to micro form have hypothesis regarding nanoparticles are more efficient on the oxidative stress. The aim of the study was to compare the toxic effects of nano and micro particles of Al2O3 and tissue differences on oxidative stress using model organism Galleria mellonella larvae. The study presented that Al2O3 NPs increased the antioxidant enzyme activities in the fat body of larvae, whereas Al2O3 MPs increased the enzyme activities in the midgut of larvae. In conclusion, heavy metal toxicity depends on the particle size, as well as tissue differences.

Effects of Aluminum Oxide Nanoparticles in the Cerebrum, Hippocampus, and Cerebellum of Male Wistar Rats and Potential Ameliorative Role of Melatonin.

Aluminum oxide nanoparticles (Al2O3 NPs) have been widely used in vaccine manufacture, food additives, human care products, and cosmetics. However, they also have adverse effects on different organs, including the liver, kidneys, and testes. Melatonin is a potent antioxidant, particularly against metals by forming melatonin-metal complexes. The present study aimed to investigate the protective effects of melatonin against Al2O3 NP-induced toxicity in the rat brain. Forty adult male Wistar rats were allocated to four groups: the untreated control (received standard diet and distilled water), Al2O3 NP-treated (received 30 mg/kg body weight Al2O3 NPs), melatonin and Al2O3 NP-treated (received 30 mg/kg body weight Al2O3 NPs + 10 mg/kg body weight melatonin), and melatonin-treated (received 10 mg/kg body weight melatonin) groups. All treatments were by oral gavages and administered daily for 28 days. Afterward, the rats were sacrificed, and samples from various brain regions (cerebrum, cerebellum, and hippocampus) were subjected to biochemical, histopathological, and immunohistochemical analyses. Al2O3 NPs substantially increased malondialdehyde, ß-amyloid 1-42 peptide, acetylcholinesterase, and ß-secretase-1 expression, whereas they markedly decreased glutathione levels. Furthermore, Al2O3 NPs induced severe histopathological alterations, including vacuolation of the neuropil, enlarged pericellular and perivascular spaces, vascular congestion, neuronal degeneration, and pyknosis. Al2O3 NP treatment also resulted in an intense positive caspase-3 immunostaining. Conversely, the administration of melatonin alleviated the adverse effects induced by Al2O3 NPs. Therefore, melatonin can diminish the neurotoxic effects induced by Al2O3 NPs.

Ameliorative effects of quercetin against hepatic toxicity of oral sub-chronic co-exposure to aluminum oxide nanoparticles and lead-acetate in male rats.

The present study was designed to evaluate the probable ameliorative role of quercetin (QCN) against oxidative hepatotoxicity induced by aluminum oxide nanoparticles (Al2O3NPs) with a diameter < 30 nm and lead acetate (Pb) co-exposure in adult male Sprague-Dawley rats. Rats were weighed and allocated to seven groups (n = 10 each) and were treated orally via orogastric gavage for 60 successive days: rats of the 1st group were kept as control given distilled water (1 ml/kg), rats of the 2nd group received 2 ml/kg BW/day corn oil; rats of the 3rd group were administered 20 mg/kg BW QCN/day; rats of the 4th group received 100 mg/kg BW Al2O3NPs; rats of the 5th group received 50 mg/kg BW Pb; rats of the 6th group co-received Al2O3NPs and Pb at the same previous doses; and rats of the 7th group were co-administered Al2O3NPs, Pb, and QCN at the same previous doses. At the end of the experiment, serum levels of alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), total, direct, indirect bilirubin, triglycerides, total cholesterol, HDL, VLDL, and LDL were estimated. The hepatic oxidative stress biomarkers as superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione peroxidase (GPx), were also evaluated. Finally, the histopathological and histomorphometric evaluations and the residues of Al and Pb in hepatic tissues were assessed. Al2O3NPs and/or Pb exposure significantly elevated lipid peroxidation levels and considerably altered the hepatic biochemical parameters; nevertheless, QCN significantly reduced hepatic enzymes compared to toxicant exposed groups. Additionally, QCN significantly improved Al2O3NPs-afforded liver tissue damage, as established in microscopic findings on the liver in the group treated with Al2O3NPs + Pb. Conclusively, QCN could be a candidate natural agent to safeguard the liver versus the co-harmful impacts of Al2O3NPs and Pb toxicity.

The comprehensive effects of aluminum oxide nanoparticles on the physiology of freshwater microalga Scenedesmus obliquus and it's phycoremediation performance for the removal of sulfacetamide.

Nanoparticles are inevitable byproducts of modern industry. However, the environmental impacts arising from industrial applications of nanoparticles are largely under-reported. This study evaluated the ecotoxicological effects of aluminum oxide nanoparticles (Al2O3NP) and its influence on sulfacetamide (SA) biodegradation by a freshwater microalga, Scenedesmus obliquus. Although Al2O3NP showed limited toxicity effect on S. obliquus, we observed the toxicity attenuation aspect of Al2O3NP in a mixture of sulfacetamide on microalgae. The addition of 100 mg L-1 of Al2O3NP and 1 mg L-1 of SA reduced total chlorophyll by 23.3% and carotenoids by 21.6% in microalgal compared to control. The gene expression study demonstrated that ATPF0C, Lhcb1, HydA, and psbA genes responsible for ATP synthesis and the photosynthetic system were significantly downregulated, while the Tas gene, which plays a major role in biodegradation of organic xenobiotic chemicals, was significantly upregulated at 1 and 100 mg L-1 of Al2O3NP. The S. obliquus removed 16.8% of SA at 15 mg L-1 in 14 days. However, the removal was slightly enhanced (18.8%) at same concentration of SA in the presence of 50 mg L-1 Al2O3NP. This result proves the stability of sulfacetamide biodegradation capacity of S. obliquus in the presence of Al2O3NP co-contamination. The metabolic analysis showed that SA was degraded into simpler byproducts such as sulfacarbamide, sulfaguanidine, sulfanilamide, 4-(methyl sulfonyl)aniline, and N-hydroxy-benzenamine which have lower ecotoxicity than SA, demonstrating that the ecotoxicity of sulfacetamide has significantly decreased after the microalgal degradation, suggesting the environmental feasibility of microalgae-mediated wastewater technology. This study provides a deeper understanding of the impact of nanoparticles such as Al2O3NP on aquatic ecosystems.

Aluminum oxide and zinc oxide induced nanotoxicity in rat brain, heart, and lung.

Nanomaterials or nanoparticles are commonly used in the cosmetics, medicine, and food industries. Many researchers studied the possible side effects of several nanoparticles including aluminum oxide (Al2O3-nps) and zinc oxide nanoparticles (ZnO-nps). Although, there is limited information available on their direct or side effects, especially on the brain, heart, and lung functions. This study aimed to investigate the neurotoxicity, cardiotoxicity, and lung toxicity induced by Al2O3-nps and ZnO-nps or in combination via studying changes in gene expression, alteration in cytokine production, tumor suppressor protein p53, neurotransmitters, oxidative stress, and the histological and morphological changes. Obtained results showed that Al2O3-nps, ZnO-nps and their combination cause an increase in 8-hydroxy-2´-deoxyguanosine (8-OHdG), cytokines, p53, oxidative stress, creatine kinase, norepinephrine, acetylcholine (ACh), and lipid profile. Moreover, significant changes in the gene expression of mitochondrial transcription factor-A (mtTFA) and peroxisome proliferator activator receptor-gamma-coactivator-1alpha (PGC-1alpha) were also noted. On the other hand, a significant decrease in the levels of antioxidant enzymes, total antioxidant capacity (TAC), reduced glutathione (GSH), paraoxonase 1 (PON1), neurotransmitters (dopamine - DA, and serotonin - SER), and the activity of acetylcholine esterase (AChE) in the brain, heart, and lung were found. Additionally, these results were confirmed by histological examinations. The present study revealed that the toxic effects were more when these nanoparticle doses are used in combination. Thus, Al2O3-nps and ZnO-nps may behave as neurotoxic, cardiotoxic, and lung toxic, especially upon exposure to rats in combination.

Involvement of Mitophagy in Primary Cultured Rat Neurons Treated with Nanoalumina.

The aim of this study was to explore the influence of the neurotoxicity of nanoalumina on primarily cultured neurons. Normal control, particle size control, aluminum, micron-alumina, and nanoalumina at 50-nm and 13-nm particle sizes were included as subjects to evaluate the level of apoptosis, necrosis, and autophagy in primarily cultured neurons and further explore the mitophagy induced by nanoalumina. The results demonstrated that nanoalumina could induce neuronal cell apoptosis, necrosis, and autophagy, among which autophagy was the most notable. When the autophagy inhibitor was added to the nanoalumina-treated group, it significantly downregulated the protein expression levels of Beclin-1 and LC3II/LC3. Observation under a transmission electron microscope and a fluorescence microscope revealed mitophagy characteristics induced by nanoalumina. Additionally, the neurotoxicological effects induced by nanoalumina were more significant than those induced by aluminum and in a particle size-dependent manner.

A stereological study reveals nanoscale-alumina induces cognitive dysfunction in mice related to hippocampal structural changes.

Aluminum (Al) is known to induce neurotoxicity in both humans and rodents. Recent evidence has indicated that the toxicity of Al Oxide (Al2O3) nanoparticles (Al-NP), one of the most abundantly used engineered nanoparticles, is far greater than that of Al itself. To date, however, no information is available regarding the effect of Al-NP on the stereological parameters of hippocampus. In particular, no stereological studies have evaluated the effect of Al-NP on hippocampal CA1, dentate gyrus volume, and number of pyramidal and granular cells. Thus, the present study aimed to take a multidimensional approach to assess the concomitant cognitive, stereological, and apoptotic changes induced by a five-day Al-NP ingestion (10 mg/kg/day) in mice. The results demonstrated that the five-day Al-NP ingestion elicited a reduced preference to explore a novel object in the novel object recognition test (a hippocampal-dependent task). Perhaps contributing to this memory deficit, Al-NP induced additional alterations in the hippocampus of male NMRI mice in terms of (1) hippocampal volume (decreased the volume of the whole hippocampus, CA1, and dentate gyrus regions), (2) cell number (decreased the number of CA1 pyramidal neurons and dentate gyrus granular cells), and (3) increased cleaved caspase-3 in the whole hippocampus. These results provided new mechanistic insight to understand the impairing effect of AL-NP on the hippocampal function and structure.

Aluminium oxide nanoparticles compromise spatial memory performance and proBDNF-mediated neuronal function in the hippocampus of rats.

BACKGROUND: Alumina nanoparticles (aluminaNPs), which are widely used in a range of daily and medical fields, have been shown to penetrate blood-brain barrier, and distribute and accumulate in different brain areas. Although oral treatment of aluminaNPs induces hippocampus-dependent learning and memory impairments, characteristic effects and exact mechanisms have not been fully elucidated. Here, male adult rats received a single bilateral infusion of aluminaNPs (10 or 20 µg/kg of body weight) into the hippocampal region, and their behavioral performance and neural function were assessed. RESULTS: The results indicated that the intra-hippocampus infusions at both doses of aluminaNPs did not cause spatial learning inability but memory deficit in the water maze task. This impairment was attributed to the effects of aluminaNP on memory consolidation phase through activation of proBDNF/RhoA pathway. Inhibition of the increased proBDNF by hippocampal infusions of p75NTR antagonist could effectively rescue the memory impairment. Incubation of aluminaNPs exaggerated GluN2B-dependent LTD induction with no effects on LTD expression in hippocampal slices. AluminaNP could also depress the amplitude of NMDA-GluN2B EPSCs. Meanwhile, increased reactive oxygen specie production was reduced by blocking proBDNF-p75NTR pathway in the hippocampal homogenates. Furthermore, the neuronal correlate of memory behavior was drastically weakened in the aluminaNP-infused groups. The dysfunction of synaptic and neuronal could be obviously mitigated by blocking proBDNF receptor p75NTR, implying the involvement of proBDNF signaling in aluminaNP-impaired memory process. CONCLUSIONS: Taken together, our findings provide the first evidence that the accumulation of aluminaNPs in the hippocampus exaggeratedly activates proBDNF signaling, which leads to neural and memory impairments.

Al2O3 nanoparticles trigger the embryonic hepatotoxic response and potentiate TNF-α-induced apoptosis-modulatory effect of p38 MAPK and JNK inhibitors.

Recent evidences illustrated that the release of aluminum oxide nanoparticles (Al2O3-NPs) into the biosphere may pose risk to the environment and cause adverse effects on living organisms including humans. The current study assessed the hepatotoxic effects of Al2O3-NPs on developing chicken embryo and cell culture models. Results demonstrated that Al2O3-NPs exposure causes histological abnormalities and increased the level of tissue damage markers (ALP, AST, and ALT) in the embryonic liver. Furthermore, increased oxidative stress (TBARS) and impaired function of antioxidant enzymes (SOD, CAT, and GPx) were also observed. Moreover, it adversely affects red blood cells (RBC) morphology, liver metabolism, and stress response gene expression (HO-1 and NQO-1). Dose-dependent ROS generation and cytotoxic response in addition to potentiating effect on tumor necrosis factor alpha (TNF-α)-induced apoptosis (caspase-3 activity) were also observed. Inhibition of p38 mitogen-activated protein kinase (p38 MAPK) and c-Jun N-terminal kinase (JNK) pathways modulates Al2O3-NPs-induced apoptosis in HepG2 cells. Novel mechanisms behind embryonic hepatotoxicity, cytotoxic potentiating effects, and possible prevention strategies have been explored.

Alumina nanoparticles-induced heterophil extracellular traps exacerbate liver injury by regulating oxidative stress and inflammation in chickens.

Widely used alumina nanoparticles (Al2O3 NPs) exposed to the environment pose a serious threat to human and animal health. The formation of heterophil extracellular traps (HETs) is a mechanism of innate immune defense against infection, but excessive HETs cause pathological damage. Here, we aim to explore the influence and mechanism of Al2O3 NPs on the formation of HETs in vitro, and further investigate the role of HETs release in histopathological damage after Al2O3 NPs treatment. Immunofluorescence analysis showed that Al2O3 NPs induced the formation of HETs, which was characterized by modified histones and elastase in the DNA backbone. Fluorescence microplate analysis showed that HETs formation was dependent on NADPH oxidase, P38, extracellular regulated protein kinases (ERK1/2) pathways and glycolysis. In vivo investigation showed that Al2O3 NPs significantly caused HETs release and liver damage. Biochemical analysis showed that Al2O3 NPs inhibited the activity of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-PX). Real-time fluorescence quantification results showed that Al2O3 NPs caused the overexpression of inflammation-related molecules interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), caspase-1 and caspase-11. All these changes were significantly changed by DNase I (Degradation reagent for HETs). Together, these suggest that Al2O3 NPs-induced HETs exacerbate liver injury by regulating oxidative stress and inflammatory responses, which provide a new perspective and potential prophylaxis and treatment targets for Al2O3 NPs toxicological research.

Toxicological Impacts on Antioxidant Responses, Stress Protein, and Genotoxicity Parameters of Aluminum Oxide Nanoparticles in the Liver of Oreochromis niloticus.

The aim of this study was to determine the toxic effects of aluminum oxide nanoparticles (Al2O3 NPs) on oxidative stress, stress protein, and genotoxicity parameters in Oreochromis niloticus. Ninety-six-hour LC50 value of Al2O3 NPs was found as 52.4 ppm for O. niloticus. The fish were exposed to 2.6 ppm (5% of the 96-h LC50) and 5.2 ppm (10% of the 96-h LC50) for 3 days and 7 days. Various biochemical parameters, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST) activities, glutathione (GSH), thiobarbituric acid reactive substance (TBARS), heat shock protein 70 (HSP70; stress protein), and genotoxicity biomarker 8-hydroxy-2-deoxyguanosine (8-OHdG) levels, were determined. Results showed that antioxidant enzymes were significantly decreased in SOD, CAT, and GPx enzyme activity, but GST enzyme activity was significantly increased in 7 days. The oxidative stress parameters, GSH levels, were significantly decreased while 8-OHdG and TBARS levels were increased in 3 and 7 days. HSP70 levels were decreased in the concentrations of Al2O3 NPs and exposure times. Our results showed that as a result of changes in oxidative stress parameters, stress protein, and genotoxicity parameters, O. niloticus liver tissue is highly sensitive and toxic to aluminum oxide nanoparticle exposure.

Evaluation of Nephrotoxicity in Oreochromis niloticus After Exposure to Aluminum Oxide Nanoparticles: Exposure and Recovery Study.

Nephrotoxic impacts of Al2O3 nanoparticles (NPs) were studied in Oreochromis niloticus after seven days of exposure and fifteen days of recovery periods. Fish were classified as group I (dechlorinated water); group II (2 mg/L Al2O3NPs); group III (4 mg/L Al2O3NPs); group IV (8 mg/L Al2O3NPs). Blood creatinine and uric acid levels showed marked increases in groups III and IV. A dose-dependent disturbance in renal antioxidant components was recorded as indicated by elevated catalase, superoxide dismutase, thiobarbituric acid reactive substances levels, and decreased glutathione reduced concentration. Renal histopathology was recorded with the highest % of appearance in group IV. A reduction in renal Al content, kidney function biomarkers (excepting group IV), and enhanced antioxidant status were observed after applying a recovery strategy. Several structural damages were identified following the recovery period, but the alteration frequencies indicated regressive histopathological changes. The Al2O3NPs-induced nephrotoxicity can be reduced after applying a suitable recovery period.

Genotoxic impact of aluminum-containing nanomaterials in human intestinal and hepatic cells.

Exposure of consumers to aluminum-containing nanomaterials (Al NMs) is an area of concern for public health agencies. As the available data on the genotoxicity of Al2O3 and Al0 NMs are inconclusive or rare, the present study investigated their in vitro genotoxic potential in intestinal and liver cell models, and compared with the ionic form AlCl3. Intestinal Caco-2 and hepatic HepaRG cells were exposed to Al0 and Al2O3 NMs (0.03 to 80 µg/cm2). Cytotoxicity, oxidative stress and apoptosis were measured using High Content Analysis. Genotoxicity was investigated through γH2AX labelling, the alkaline comet and micronucleus assays. Moreover, oxidative DNA damage and carcinogenic properties were assessed using the Fpg-modified comet assay and the cell transforming assay in Bhas 42 cells respectively. The three forms of Al did not induce chromosomal damage. However, although no production of oxidative stress was detected, Al2O3 NMs induced oxidative DNA damage in Caco-2 cells but not likely related to ion release in the cell media. Considerable DNA damage was observed with Al0 NMs in both cell lines in the comet assay, likely due to interference with these NMs. No genotoxic effects were observed with AlCl3. None of the Al compounds induced cytotoxicity, apoptosis, γH2AX or cell transformation.

Teratogenicity of 30 nm Aluminum Oxide Nanoparticles (Al2O3NPs) in Rats by Gavage.

Aluminum oxide nanoparticles (Al2O3NPs) are one class of widely used nanomaterials. However, the teratogenicity toxicity of Al2O3NPs in mammal remains poorly understood. This study was aimed to evaluate the teratogenicity of Al2O3NPs in Sprague Dawley (SD) rats by gavage and to compare the effects of Al2O3NPs to those of equivalent dose of microscale aluminum oxide (bulk Al2O3). Sixty pregnant rats were randomly divided into 5 groups and treated with 100 and 200 mg/kg body weight (bw) Al2O3NPs (30 nm), 200 mg/kg bulk Al2O3, deionized water (as the negative control), and 300 mg/kg aspirin (as the positive control). Rats were exposed daily by oral gavage from the 7th day of gestation for 10 consecutive days and sacrificed on the 20th day of gestation. Results of the study showed that there were no significant effects of Al2O3NPs on pregnant rats (clinical signs, body weight, food consumption, ovary and uterus weight, number of corpora lutea) and fetuses (body weight, sex, body length, tail length, skeletal and visceral development). Under the experimental conditions of the present study, 10 consecutive days of repeated oral administration of Al2O3NPs at doses of up to 200 mg/kg/day did not induce any treatment-related teratogenicity in SD rats. Accordingly, the NOAEL was determined to be 200 mg/kg Al2O3NPs (106 mg Al/kg bw/day) in rats. The teratogenic effects of Al2O3NPs in rats were comparable to those of the bulk Al2O3 of same doses (200 mg/kg).

Subchronic Toxicity Evaluation of Aluminum Oxide Nanoparticles in Rats Following 28-Day Repeated Oral Administration.

Several studies on the potential adverse effects of aluminum oxide nanoparticles (Al2O3NPs) have reported conflicting results. The present study investigated the potential adverse effects of Al2O3NPs in Sprague-Dawley rats following 28-day repeated oral administration. In addition, we aimed to determine the target organ and no-observed-adverse-effect level (NOAEL) of Al2O3NPs. Al2O3NPs was administered once daily by gavage to male and female rats at dose levels of 0, 500, and 1000 mg/kg/day for 28 days. There were no treatment-related adverse effects as indicated by the clinical signs, body weight, food consumption, urinalysis, ophthalmology, hematology, serum biochemistry, gross pathology, organ weight, and histopathology at all the tested doses. Under the experimental conditions of the present study, 28-day repeated oral administration of Al2O3NPs at doses of up to 1000 mg/kg/day did not induce any treatment-related systemic toxicity in male and female rats. The NOAEL of Al2O3NPs was set at 1000 mg/kg/day in both male and female rats and no target organs were identified.

Nose-only inhalations of high-dose alumina nanoparticles/hydrogen chloride gas mixtures induce strong pulmonary pro-inflammatory response: a pilot study.

OBJECTIVE: Solid composite propellants combustion, in aerospace and defense fields, can lead to complex aerosols emission containing high concentrations of alumina nanoparticles (Al2O3 NPs) and hydrogen chloride gas (HClg). Exposure to these mixtures by inhalation is thus possible but literature data toward their pulmonary toxicity are missing. To specify hazards resulting from these combustion aerosols, a pilot study was implemented. MATERIALS AND METHODS: Male Wistar rats were nose-only exposed to Al2O3 NPs (primary size 13 nm, 10 g/L suspension leading to 20.0-22.1 mg/m3 aerosol) and/or to HClg aerosols (5 ppm target concentration) following two exposure scenarios (single exposures (SE) or repeated exposures (RE)). Bronchoalveolar lavage fluids (BALF) content and lungs histopathology were analyzed 24 h after exposures. RESULTS: Repeated co-exposures increased total proteins and LDH concentrations in BALF indicating alveolar-capillary barrier permeabilization and cytolysis. Early pulmonary inflammation was induced after RE to Al2O3 NPs ± HClg resulting in PMN, TNF-α, IL-1ß, and GRO/KC increases in BALF. Both exposure scenarios resulted in pulmonary histopathological lesions (vascular congestions, bronchial pre-exfoliations, vascular and interalveolar septum edemas). Lung oxidative damages were observed in situ following SE. CONCLUSION: Observed biological effects are dependent on both aerosol content and exposure scenario. Results showed an important pro-inflammatory effect of Al2O3 NPs/HClg mixtures on the lungs of rat 24 h after exposure. This pilot study raises concerns toward potential long-term pulmonary toxicity of combustion aerosols and highlights the importance for further studies to be led in order to define dose limitations and exposure thresholds for risk management at the work place.