Anemia and genotoxicity induced by sub-chronic intragastric treatment of rats with titanium dioxide nanoparticles

Genotoxicity assessment of food-grade titanium dioxide

Food-grade titanium dioxide (E171 in Europe), which contains nanoscale particles (NPs), has been approved and used as a white pigment in various common foods. Concerns are growing over the use of E171 as a safe food additive. The purpose of the present research is to evaluate the genotoxicity of E171 using in vivo and in vitro testing systems. In vitro studies, Chinese hamster lung (V79) fibroblast cells were exposed to E171 at doses of 25, 50, 100, and 200 μg/mL. No gene mutations were observed after 24 h of treatment at any concentration using the hypoxanthine guanine phosphoribosyltransferase (Hprt) gene mutation assay. In vivo study, the healthy Kunming mice and SD rats were exposed to E171 through intragastric administration at doses of 250, 500 and 1000 mg/kg body weight every day for 15 days. Genotoxic potential of E171 was evaluated by micronucleus (MN) and comet assays in accordance with the OECD guideline. However, the results showed that E171 did not increase the frequency of bone marrow micronuclei or induce DNA strand breaks in rat liver cells at the doses used in this experiments. Under the conditions described in this report, E171 was concluded to be negative in these in vivo and in vitro genotoxicity tests. These findings suggest that E171 is not genotoxic, offering valuable data for risk assessment.

Ultrasound-Based Micro-/Nanosystems for Biomedical Applications

Due to the intrinsic non-invasive nature, cost-effectiveness, high safety, and real-time capabilities, besides diagnostic imaging, ultrasound as a typical mechanical wave has been extensively developed as a physical tool for versatile biomedical applications. Especially, the prosperity of nanotechnology and nanomedicine invigorates the landscape of ultrasound-based medicine. The unprecedented surge in research enthusiasm and dedicated efforts have led to a mass of multifunctional micro-/nanosystems being applied in ultrasound biomedicine, facilitating precise diagnosis, effective treatment, and personalized theranostics. The effective deployment of versatile ultrasound-based micro-/nanosystems in biomedical applications is rooted in a profound understanding of the relationship among composition, structure, property, bioactivity, application, and performance. In this comprehensive review, we elaborate on the general principles regarding the design, synthesis, functionalization, and optimization of ultrasound-based micro-/nanosystems for abundant biomedical applications. In particular, recent advancements in ultrasound-based micro-/nanosystems for diagnostic imaging are meticulously summarized. Furthermore, we systematically elucidate state-of-the-art studies concerning recent progress in ultrasound-based micro-/nanosystems for therapeutic applications targeting various pathological abnormalities including cancer, bacterial infection, brain diseases, cardiovascular diseases, and metabolic diseases. Finally, we conclude and provide an outlook on this research field with an in-depth discussion of the challenges faced and future developments for further extensive clinical translation and application.

Evaluation of possible cytotoxic, genotoxic and epigenotoxic effects of titanium dioxide nanoparticles and possible protective effect of melatonin

Nanoparticles (NPs) are particles of matter that are between 1 to 100 nm in diameter. They are suggested to cause toxic effects in both humans and environment thorough different mechanisms. However, their toxicity profile may be different from the parent material. Titanium dioxide (TiO2) NPs are widely used in cosmetic, pharmaceutical and food industries. As a white pigment, the use of TiO2 is used in food coloring, industrial paints, clothing and UV filters has increased tremendously in recent years. Melatonin, on the other hand, is a well-known antioxidant and may prevent oxidative stress caused by a variety of different substances, including NPs. In the current study, we aimed to comparatively investigate the effects of normal-sized TiO2 (220 nm) and nano-sized TiO2 (21 nm) on cytopathology, cytotoxicity, oxidative damage (lipid peroxidation, protein oxidation and glutathione), genotoxicity (8-hydroxydeoxyguanosine), apoptosis (caspase 3, 8 and 9) and epigenetic alterations (global DNA methylation, H3 acetylation) on 3T3 fibroblast cells. In addition, the possible protective effects of melatonin, which is known to have strong antioxidant effects, against the toxicity of TiO2 were also evaluated. Study groups were: a. the control group; b. melatonin group; c. TiO2 group; d. nano-sized TiO2 group; e. TiO2 + melatonin group and f. nano-sized TiO2 + melatonin group. We observed that both normal-sized and nano-sized TiO2 NPs showed significant toxic effects. However, TiO2 NPs caused higher DNA damage and global DNA methylation compared to normal-sized TiO2 whereas normal-sized TiO2 led to lower H3 acetylation vs. TiO2 NPs. Melatonin showed partial protective effect against the toxicity caused by TiO2 NPs.

Gastrointestinal tract exposure to particles and DNA damage in animals: A review of studies before, during and after the peak of nanotoxicology

Humans ingest particles and fibers on daily basis. Non-digestible carbohydrates are beneficial to health and food additives are considered safe. However, titanium dioxide (E171) has been banned in the European Union because the European Food Safety Authority no longer considers it non-genotoxic. Ingestion of microplastics and nanoplastics are novel exposures; their potential hazardous effects to humans have been under the radar for many years. In this review, we have assessed the association between oral exposure to man-made particles/fibers and genotoxicity in gastrointestinal tract cells and secondary tissues. We identified a total of 137 studies on oral exposure to particles and fibers. This was reduced to 49 papers with sufficient quality and relevance, including exposures to asbestos, diesel exhaust particles, titanium dioxide, silver nanoparticles, zinc oxide, synthetic amorphous silica and certain other nanomaterials. Nineteen studies show positive results, 25 studies show null results, and 5 papers show equivocal results on genotoxicity. Recent studies seem to show null effects, whereas there is a higher proportion of positive genotoxicity results in early studies. Genotoxic effects seem to cluster in studies on diesel exhaust particles and titanium dioxide, whereas studies on silver nanoparticles, zinc oxide and synthetic amorphous silica seem to show mainly null effects. The most widely used genotoxic tests are the alkaline comet assay and micronucleus assay. There are relatively few results on genotoxicity using reliable measurements of oxidatively damaged DNA, DNA double strand breaks (γH2AX assay) and mutations. In general, evidence suggest that oral exposure to particles and fibers is associated with genotoxicity in animals.

Genotoxicity assessment of titanium dioxide nanoparticles using a standard battery of in vivo assays

As one representative of nanometal oxides, titanium dioxide nanoparticles (TiO2-NPs) have been widely used, particularly in the food industry. The genotoxicity of TiO2-NPs has attracted great attention over the years. This study was undertaken to investigate the chromosome and DNA damage effects of TiO2-NPs (0, 50, 150, and 500 mg/kg BW) using rodent models. After a comprehensive characterization, we conducted a standard battery of in vivo genotoxicity tests, including the chromosomal aberration test (CA), micronucleus (MN) test, and the comet test. The results of all these tests were negative. There were no structural or numerical chromosomal abnormalities in mice bone marrow cells, no increase in the frequency of micronucleated polychromatic erythrocytes in mice bone marrow cells, and no elevation in % tail DNA in rat hepatocytes. This indicated that TiO2-NPs did not cause chromosomal damage or have a direct impact on DNA. These findings suggested that TiO2-NPs did not exhibit genotoxicity and provided valuable data for risk assessment purposes.

Adverse Outcome Pathways Associated with the Ingestion of Titanium Dioxide Nanoparticles-A Systematic Review

Titanium dioxide nanoparticles (TiO₂-NPs) are widely used, and humans are exposed through food (E171), cosmetics (e.g., toothpaste), and pharmaceuticals. The oral and gastrointestinal (GIT) tract are the first contact sites, but it may be systemically distributed. However, a robust adverse outcome pathway (AOP) has not been developed upon GIT exposure to TiO₂-NPs. The aim of this review was to provide an integrative analysis of the published data on cellular and molecular mechanisms triggered after the ingestion of TiO₂-NPs, proposing plausible AOPs that may drive policy decisions. A systematic review according to Prisma Methodology was performed in three databases of peer-reviewed literature: Pubmed, Scopus, and Web of Science. A total of 787 records were identified, screened in title/abstract, being 185 used for data extraction. The main endpoints identified were oxidative stress, cytotoxicity/apoptosis/cell death, inflammation, cellular and systemic uptake, genotoxicity, and carcinogenicity. From the results, AOPs were proposed where colorectal cancer, liver injury, reproductive toxicity, cardiac and kidney damage, as well as hematological effects stand out as possible adverse outcomes. The recent transgenerational studies also point to concerns with regard to population effects. Overall, the findings further support a limitation of the use of TiO₂-NPs in food, announced by the European Food Safety Authority (EFSA).

Cellular and Molecular Mechanisms of Toxicity of Ingested Titanium Dioxide Nanomaterials

An exponential increase in products containing titanium dioxide nanomaterials (TiO2), in agriculture, food and feed industry, lead to increased oral exposure to these nanomaterials (NMs). Thus, the gastrointestinal tract (GIT) emerges as a possible route of exposure that may drive systemic exposure, if the intestinal barrier is surpassed. NMs have been suggested to produce adverse outcomes, such as genotoxic effects, that are associated with increased risk of cancer, leading to a concern for public health. However, to date, the differences in the physicochemical characteristics of the NMs studied and other variables in the test systems have generated contradictory results in the literature. Processes like human digestion may change the NMs characteristics, inducing unexpected toxic effects in the intestine. Using TiO2 as case-study, this chapter provides a review of the works addressing the interactions of NMs with biological systems in the context of intestinal tract and digestion processes, at cellular and molecular level. The knowledge gaps identified suggest that the incorporation of a simulated digestion process for in vitro studies has the potential to improve the model for elucidating key events elicited by these NMs, advancing the nanosafety studies towards the development of an adverse outcome pathway for intestinal effects.

Advances in genotoxicity of titanium dioxide nanoparticles in vivo and in vitro

Titanium dioxide nanoparticles (TiO₂ NPs) are currently one of the most widely used nanomaterials. Due to an increasing scope of applications, the exposure of humans to TiO₂ NP is inevitable, such as entering the body through the mouth with food additives or drugs, invading the damaged skin with cosmetics, and entering the body through the respiratory tract during the process of production and handling. Compared with TiO₂ coarse particles, TiO₂ NPs have stronger conductivity, reaction activity, photocatalysis, and permeability, which may lead to greater toxicity to organisms. Given that TiO₂ was classified as a category 2B carcinogen (possibly carcinogenic to humans), the genotoxicity of TiO₂ NPs has become the focus of attention. There have been a series of previous studies investigating the potential genotoxicity of TiO₂ NPs, but the existing research results are still controversial and difficult to conclude. More than half of studies have shown that TiO₂ NPs can cause genotoxicity, suggesting that TiO₂ NPs are likely to be genotoxic to humans. And the genotoxicity of TiO₂ NPs is closely related to the exposure concentration, mode and time, and experimental cells/animals as well as its physicochemical properties (crystal type, size, and shape). This review summarized the latest research progress of related genotoxic effects through in vivo studies and in vitro cell tests, hoping to provide ideas for the evaluation of TiO₂ NPs genotoxicity.

Safety assessment of titanium dioxide (E171) as a food additive

The present opinion deals with an updated safety assessment of the food additive titanium dioxide (E 171) based on new relevant scientific evidence considered by the Panel to be reliable, including data obtained with TiO2 nanoparticles (NPs) and data from an extended one-generation reproductive toxicity (EOGRT) study. Less than 50% of constituent particles by number in E 171 have a minimum external dimension < 100 nm. In addition, the Panel noted that constituent particles < 30 nm amounted to less than 1% of particles by number. The Panel therefore considered that studies with TiO2 NPs < 30 nm were of limited relevance to the safety assessment of E 171. The Panel concluded that although gastrointestinal absorption of TiO2 particles is low, they may accumulate in the body. Studies on general and organ toxicity did not indicate adverse effects with either E 171 up to a dose of 1,000 mg/kg body weight (bw) per day or with TiO2 NPs (> 30 nm) up to the highest dose tested of 100 mg/kg bw per day. No effects on reproductive and developmental toxicity were observed up to a dose of 1,000 mg E 171/kg bw per day, the highest dose tested in the EOGRT study. However, observations of potential immunotoxicity and inflammation with E 171 and potential neurotoxicity with TiO2 NPs, together with the potential induction of aberrant crypt foci with E 171, may indicate adverse effects. With respect to genotoxicity, the Panel concluded that TiO2 particles have the potential to induce DNA strand breaks and chromosomal damage, but not gene mutations. No clear correlation was observed between the physico-chemical properties of TiO2 particles and the outcome of either in vitro or in vivo genotoxicity assays. A concern for genotoxicity of TiO2 particles that may be present in E 171 could therefore not be ruled out. Several modes of action for the genotoxicity may operate in parallel and the relative contributions of different molecular mechanisms elicited by TiO2 particles are not known. There was uncertainty as to whether a threshold mode of action could be assumed. In addition, a cut-off value for TiO2 particle size with respect to genotoxicity could not be identified. No appropriately designed study was available to investigate the potential carcinogenic effects of TiO2 NPs. Based on all the evidence available, a concern for genotoxicity could not be ruled out, and given the many uncertainties, the Panel concluded that E 171 can no longer be considered as safe when used as a food additive.

Titanium dioxide nanoparticle genotoxicity: A review of recent in vivo and in vitro studies

Titanium dioxide nanoparticles (TiO2 NPs, size <100 nm) find applications in a wide range of products including food and cosmetics. Studies have found that exposure to TiO2 NPs can cause inflammation, cytotoxicity, genotoxicity and cell apoptosis. In this article, we have reviewed the recent literature on the potential of TiO2 NPs to cause genotoxicity and summarized the results of two standard genotoxicity assays, the comet and micronucleus (MN) assays. Analysis of these peer-reviewed publications shows that the comet assay is the most common genotoxicity test, followed by MN, Ames, and chromosome aberration tests. These assays have reported positive as well as negative results, although there is inconsistency in some results that need to be confirmed further by well-designed experiments. We also discuss the possible mechanisms of TiO2 NP genotoxicity and point out areas that warrant further research.

Possible effects of titanium dioxide particles on human liver, intestinal tissue, spleen and kidney after oral exposure

Recent studies reported adverse liver effects and intestinal tumor formation after oral exposure to titanium dioxide (TiO₂). Other oral toxicological studies, however, observed no effects on liver and intestine, despite prolonged exposure and/or high doses. In the present assessment, we aimed to better understand whether TiO₂ can induce such effects at conditions relevant for humans. Therefore, we focused not only on the clinical and histopathological observations, but also used Adverse Outcome Pathways (AOPs) to consider earlier steps (Key Events). In addition, aiming for a more accurate risk assessment, the available information on organ concentrations of Ti (resulting from exposure to TiO₂) from oral animal studies was compared to recently reported concentrations found in human postmortem organs. The overview obtained with the AOP approach indicates that TiO₂ can trigger a number of key events in liver and intestine: Reactive Oxygen Species (ROS) generation, induction of oxidative stress and inflammation. TiO₂ seems to be able to exert these early effects in animal studies at Ti liver concentrations that are only a factor of 30 and 6 times higher than the median and highest liver concentration found in humans, respectively. This confirms earlier conclusions that adverse effects on the liver in humans as a result of (oral) TiO₂ exposure cannot be excluded. Data for comparison with Ti levels in human intestinal tissue, spleen and kidney with effect concentrations were too limited to draw firm conclusions. The Ti levels, though, are similar or higher than those found in liver, suggesting these tissues may be relevant too.

Titanium Dioxide Nanoparticles in Food and Personal Care Products-What Do We Know about Their Safety?

Titanium dioxide (TiO2) is a material of diverse applications commonly used as a food additive or cosmetic ingredient. Its prevalence in products of everyday use, especially in nanosize, raises concerns about safety. Current findings on the safety of titanium dioxide nanoparticles (TiO2 NPs) used as a food additive or a sunscreen compound are reviewed and systematized in this publication. Although some studies state that TiO2 NPs are not harmful to humans through ingestion or via dermal exposure, there is a considerable number of data that demonstrated their toxic effects in animal models. The final agreement on the safety of this nanomaterial has not yet been reached among researchers. There is also a lack of official, standardized guidelines for thorough characterization of TiO2 NPs in food and cosmetic products, provided by international authorities. Recent advances in the application of 'green-synthesized' TiO2 NPs, as well as comparative studies of the properties of 'biogenic' and 'traditional' nanoparticles, are presented. To conclude, perspectives and directions for further studies on the toxicity of TiO2 NPs are proposed.

Comparative study of toxicological assessment of yttrium oxide nano- and microparticles in Wistar rats after 28 days of repeated oral administration

Despite their enormous advantages, nanoparticles (NPs) have elicited disquiet over their safety. Among the numerous NPs, yttrium oxide (Y2O3) NPs are utilised in many applications. However, knowledge about their toxicity is limited, and it is imperative to investigate their potential adverse effects. Therefore, this study explored the effect of 28 days of repeated oral exposure of Wistar rats to 30, 120 and 480 mg/kg body weight (bw) per day of Y2O3 NPs and microparticles (MPs). Before initiation of the study, characterisation of the particles by transmission electron microscopy, dynamic light scattering, Brunauer-Emmett-Teller and laser Doppler velocimetry was undertaken. Genotoxicity was evaluated using the comet and micronucleus (MN) assays. Biochemical markers aspartate transaminase, alanine transaminase, alkaline phosphatase, malondialdehyde, superoxide dismutase, reduced glutathione, catalase and lactate dehydrogenase in serum, liver and kidney were determined. Bioaccumulation of the particles was analysed by inductively coupled plasma optical emission spectrometry. The results of the comet and MN assays showed significant differences between the control and groups treated with 120 and 480 mg/kg bw/day Y2O3 NPs. Significant biochemical alterations were also observed at 120 and 480 mg/kg bw/day. Haematological and histopathological changes were documented. Yttrium (Y) biodistribution was detected in liver, kidney, blood, intestine, lungs, spleen, heart and brain in a dose- and the organ-dependent manner in both the particles. Further, the highest levels of Y were found in the liver and the lowest in the brain of the treated rats. More of the Y from NPs was excreted in the urine than in the faeces. Furthermore, NP-treated rats exhibited much higher absorption and tissue accumulation. These interpretations furnish rudimentary data of the apparent genotoxicity of NPs and MPs of Y2O3 as well as the biodistribution of Y. A no-observed adverse effect level of 30 mg/kg bw/day was found after oral exposure of rats to Y2O3 NPs.

Mechanism of Action of TiO2: Recommendations to Reduce Uncertainties Related to Carcinogenic Potential

The Risk Assessment Committee of the European Chemicals Agency issued an opinion on classifying titanium dioxide (TiO₂) as a suspected human carcinogen upon inhalation. Recent animal studies indicate that TiO₂ may be carcinogenic through the oral route. There is considerable uncertainty on the carcinogenicity of TiO₂, which may be decreased if its mechanism of action becomes clearer. Here we consider adverse outcome pathways and present the available information on each of the key events (KEs). Inhalation exposure to TiO₂ can induce lung tumors in rats via a mechanism that is also applicable to other poorly soluble, low-toxicity particles. To reduce uncertainties regarding human relevance, we recommend gathering information on earlier KEs such as oxidative stress in humans. For oral exposure, insufficient information is available to conclude whether TiO₂ can induce intestinal tumors. An oral carcinogenicity study with well-characterized (food-grade) TiO₂ is needed, including an assessment of toxicokinetics and early KEs.

Genotoxicity assessment of titanium dioxide nanoparticle accumulation of 90 days in the liver of gpt delta transgenic mice

Backgound

A variety of in vivo and in vitro studies to assess the genotoxicity of titanium dioxide nanoparticles (TiO₂ NPs) have been reported, but the results are inconsistent. Recently, we reported that TiO₂ NPs exhibit no genotoxic effects in the liver and erythrocytes during a relatively brief period following intravenous injection into mice. However, there is no information about long-term genotoxicity due to TiO₂ NP accumulation in tissues. In this study, we investigated the long-term mutagenic effects of TiO₂ NPs and the localization of residual TiO₂ NPs in mouse liver after multiple intravenous injections.

Results

Male gpt delta C57BL/6 J mice were administered with various doses of TiO₂ NPs weekly for 4 consecutive weeks. The long-term mutagenic effects on the liver were analyzed using gpt and Spi⁻ mutation assays 90 days after the final injection. We also quantified the amount of titanium in the liver using inductively coupled plasma mass spectrometry and observed the localization of TiO₂ NPs in the liver using transmission electron microscopy. Although TiO₂ NPs were found in the liver cells, the gpt and Spi⁻ mutation frequencies in the liver were not significantly increased by the TiO₂ NP administration.

Conclusions

These results clearly show that TiO₂ NPs have no mutagenic effects on the liver, even though the particles remain in the liver long-term.

Single red blood cell analysis reveals elevated hemoglobin in poikilocytes

Abnormally shaped red blood cells (RBCs), called poikilocytes, can cause anemia. At present, the biochemical abnormalities in poikilocytes are not well understood. Normal RBCs and poikilocytes were analyzed using whole-blood and single-cell methods. Poikilocytes were induced in rat blood by intragastrically administering titanium dioxide (TiO₂) nanoparticles. Complete blood count and inductively coupled plasma mass spectrometry analyses were performed on whole-blood to measure average RBC morphology, blood hemoglobin (HGB), iron content, and other blood parameters. Follow-up confocal Raman spectroscopy was performed on single RBCs to analyze cell-type-specific HGB content. Two types of poikilocytes, acanthocytes and echinocytes, were observed in TiO₂ blood samples, along with normal RBCs. Acanthocytes (diameter 7.7  ±  0.5  μm) and echinocytes (7.6  ±  0.6  μm) were microscopically larger (p  <  0.05) than normal RBCs (6.6  ±  0.4  μm) found in control blood samples (no TiO₂ administration). Similarly, mean corpuscular volume was higher (p  <  0.05) in TiO₂ whole-blood (70.70  ±  1.97  fl) than in control whole-blood (67.42  ±  2.03  fl). Poikilocytes also had higher HGB content. Mean corpuscular hemoglobin was higher (p  <  0.05) in TiO₂ whole-blood (21.84  ±  0.75  pg) than in control whole-blood (20.8  ±  0.32  pg). Iron content was higher (p  <  0.001) in TiO₂ whole-blood (697.0  ±  24.5  mg  /  l) than in control whole-blood (503.4  ±  38.5  mg  /  l), which supports elevated HGB as iron is found in HGB. HGB-associated Raman bands at 1637, 1585, and 1372  cm^-  1 had higher (p  <  0.001) amplitudes in acanthocytes and echinocytes than in RBCs from control blood and normal RBCs from TiO₂ blood. Further, the 1585-cm^-  1 band had a lower (p  <  0.05) amplitude in normal RBCs from TiO₂ versus control RBCs. This represents biochemical abnormalities in normal appearing RBCs. Overall, poikilocytes, especially acanthocytes, have elevated HGB.

In deep evaluation of the neurotoxicity of orally administered TiO2 nanoparticles

Titanium dioxide nanoparticles were widely used in food as dietary supplements, in drugs, in toothpaste, ect. Few numbers of studies were interested to the neurotoxicity of TiO₂ NPs through oral pathway. The present study aims firstly to understand the connection between the physicochemical properties of TiO₂ NPs and their associated toxicological oral pathway by evaluation the colloidal stability of TiO₂ NPs over time in different media simulating physiological gastric, intestinal and serum conditions at 37 °C to be close to the oral administraton. Secondly, this study aims to evaluate the neurotoxicity of a subchronic intragastric administration of TiO₂ NPs to rats. Different doses of anatase TiO₂ NPs were administrated to Wistar rats every day for consecutives eight weeks. Titanium (Ti) content in brain, oxidative antioxidant biomarkers, lipid peroxidation, nitric oxide (NO) levels, tumor necrosis factor-alpha (TNF-α) levels, histophatological changes, degenerated and apoptosis neurons were investigated. Results suggested that TiO₂ NPs can reach the brain and cross the brain blood barrier (BBB) to been accumulated in the brain of rats causing cerebral oxidative stress damage, increasing NO levels and histopathological injury. At higher dose, we observed the most cerebral injury by the highest accumulation of Ti and by the remarkable increase of TNF-α besides to the most increase of degenerated and apoptosis neurons in the brain of exposed rats. TiO₂ NPs led to a neurotoxic damage accompanied by the increase of degenerated and apoptotic neurons in cerebral cortex.

Magnetic nanoparticles-loaded liposomes as a novel treatment agent for iron deficiency anemia: In vivo study

Iron deficiency anemia (IDA) is a major worldwide public health problem. This is due to its prevalence among infants, children, adolescents, pregnant and reproductive age women. Ferrous sulfate (FeSO₄) is the first line therapy for iron IDA. Unfortunately, it is reported that FeSO₄ suffers from low absorption rate in the body and itself exhibits severe side effects. Herein, iron oxide magnetic nanoparticles-loaded liposomes (LMNPs) are prepared, characterized and evaluated as a treatment regimen for IDA in Wistar rats (as an animal model). Iron oxide magnetic nanoparticles (MNPs) are prepared and loaded into liposomes using the thin film hydration method. The size of the prepared formulations is in the range 10-100 nm, thus it can avoid the reticular endothelial system (RES), and increased their blood circulation time. For in vivo assessment, thirty-five Wistar rats are divided into 5 groups (n = 7): negative control group, positive control group, and three groups treated with different iron formulations (FeSO₄, MNPs and LMNPs). Anemia is induced in the anemic groups by the bleeding method and then treatment started with different iron compounds administrated orally for 13 days. Hematological parameters are followed up during the treatment period. Results indicate that, in the LMNPs group, the hematological parameters turn to normal values and the histopathological structures of the liver, spleen and kidney remain normal. This proves that liposome increases the bioavailability of MNPs. In conclusion, LMNPs demonstrate superiority as a therapeutic regimen for the treatment of IDA among the tested iron formulations.

Evaluation of cytogenotoxicity and oxidative stress parameters in male Swiss mice co-exposed to titanium dioxide and zinc oxide nanoparticles

A number of studies have investigated the adverse toxic effects of titanium dioxide (TiO₂) nanoparticles (NPs) or zinc oxide (ZnO) NPs. Information on the potential genotoxic effects of the interactions of TiO₂ NPs and ZnO NPs in vivo is lacking. Therefore, this study was designed to investigate the cytogenotoxicity of TiO₂ NPs or ZnO NPs alone or their mixtures using the bone marrow micronucleus assay, and mechanism of damage through the evaluation of oxidative stress parameters in the liver and kidney tissues of Swiss mice. Intraperitoneal administration of doses between 9.38 and 150.00 mg/kg of TiO₂ NPs or ZnO NPs or TiO₂ NPs + ZnO NPs was performed for 5 and 10 days, respectively. TiO₂ NPs alone induced a significant (P <  0.05) increase in micronucleated (Mn) polychromatic erythrocytes (PCEs) at the applied doses compared with the negative controls, with a significant difference between 5 and 10 days for TiO₂ NPs alone and TiO₂ NPs + ZnO NPs. Concurrently, TiO₂ NPs alone for 5 days and TiO₂ NPs and TiO₂ NPs + ZnO NPs for 10 days significantly (P <  0.05) decreased the percentage PCE: normochromatic erythrocyte (NCE) indicating cytotoxicity; with a significant difference between the two periods. Significant (P <  0.001) changes in the activities of superoxide dismutase (SOD) and catalase (CAT), and levels of reduced glutathione (GSH) and malondialdehyde (MDA) were observed in the liver and kidney of mice exposed to TiO₂ NPs or ZnO NPs alone or their mixtures. These results suggest that TiO₂ NPs alone was genotoxic; TiO₂ NPs and TiO₂ NPs + ZnO NPs were noticeably cytotoxic while ZnO NPs was not cytogenotoxic. The individual NPs or their mixtures induced oxidative stress.

Subchronic and chronic toxicity evaluation of inorganic nanoparticles for delivery applications

Inorganic nanoparticles provide the opportunity to localize bioactive agents to the target sites and protect them from degradation. In many cases, acute toxicities of inorganic nanoparticles used for delivery applications have been investigated. However, little information is available regarding the long-term toxicity of such materials. This review focuses on the importance of subchronic and chronic toxicity assessment of inorganic nanoparticles investigated for delivery applications. We have attempted to provide a comprehensive review of the available literature for chronic toxicity assessment of inorganic nanoparticles. Where possible correlations are made between particle composition, physiochemical properties, duration, frequency and route of administration, as well as the sex of animals, with tissue and blood toxicity, immunotoxicity and genotoxicity. A critical gap analysis is provided and important factors that need to be considered for long-term toxicology of inorganic nanoparticles are discussed.

Acute and subacute oral toxicity of copper oxide nanoparticles in female albino Wistar rats

The extensive use of copper oxide nanoparticles (CuO-NPs) in various industries and their wide range of applications have led to their accumulation in different ecological niches of the environment. This excess exposure raises the concern about its potential toxic effects on various organisms including humans. However, the hazardous potential of CuO-NPs in the literature is elusive, and it is essential to study its toxicity in different biological models. Hence, we have conducted single acute dose (2000 mg/kg) and multiple dose subacute (30, 300 and 1000 mg/kg daily for 28 days) oral toxicity studies of CuO-NPs in female albino Wistar rats following OECD guidelines 420 and 407 respectively. Blood analysis, tissue aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and acetylcholinesterase, superoxide dismutase, catalase, lipid malondialdehyde and reduced glutathione assays, and histopathology of the tissues were carried out. The higher dose treatments of the acute and subacute study caused significant alterations in biochemical and antioxidant parameters of the liver, kidney and brain tissues of the rat. In addition, histopathological evaluation of these three organs of treated rats showed significantly high abnormalities in their histoarchitecture when compared to control rats. We infer from the results that the toxicity observed in the liver, kidney and brain of treated rats could be due to the increased generation of reactive oxygen species by CuO-NPs.

Acute oral toxicity study of magnesium oxide nanoparticles and microparticles in female albino Wistar rats

Advancements in nanotechnology have led to the development of the nanomedicine, which involves nanodevices for diagnostic and therapeutic purposes. A key requirement for the successful use of the nanoparticles (NPs) in biomedical applications is their good dispensability, colloidal stability in biological media, internalization efficiency, and low toxicity. Therefore, toxicological profiling is necessary to understand the mechanism of NPs and microparticles (MPs). MgO NPs have attracted wide scientific interest due to ease of synthesis, chemical stability and unique properties. However, their toxic effects on humans should also be of concern with the increased applications of nano MgO. The present study was aimed to assess the toxicological potential of MgO NPs in comparison to their micron counterparts in female Wistar rats. Toxicity was evaluated using genotoxicity, histological, biochemical, antioxidant and biodistribution parameters post administration of MgO particles to rats through oral route. The results obtained from the investigation revealed that the acute exposure to the high doses of MgO NPs produced significant (p < 0.01) DNA damage and biochemical alterations. Antioxidant assays revealed prominent oxidative stress at the high dose level for both the particles. Toxicokinetic analysis showed significant levels of Mg accumulation in the liver and kidney tissues apart from urine and feces. Further, mechanistic investigational reports are warranted to document safe exposure levels and health implications post exposure to high levels of NPs.

Rosmarinus officinalis L. ameliorates titanium dioxide nanoparticles and induced some toxic effects in rats' blood

Titanium dioxide nanoparticles (TiO₂ NPs) have been widely used as a white pigment in food and drugs. The most important route of human exposure to TiO₂ is through food and drug products containing TiO₂ additives. This study investigates the efficacy of an oral traditional use of rosemary extract in ameliorating some toxic effects induced on blood of TiO₂ NP-intoxicated rats. Rats were given rosemary extract via intragastric administration 1 h before the intragastric administration of 100 mg/kg/day TiO₂ NPs (10 nm) for 60 days. TiO₂ NPs significantly increased serum cholesterol, glucose, and triglyceride levels of rats. They also induced significant oxidative stress and inflammatory and caused DNA damage in peripheral blood leukocytes. The rosemary extract appears to have a significant protective effect by lowering glucose level properties, restoring the lipid profile and showing an antioxidative, anti-inflammatory, and antigenotoxic properties against TiO₂ NPs toxicity. In conclusion, this study gives an encouraging scientific basis for consumers of rosemary leaves to keep on with this culinary habit.

Blood toxic metals and hemoglobin levels in Mexican children

Metal toxicity can cause hematologic abnormalities and hemolysis. To evaluate the relationship of anemia with metal contamination in children, the following elements were quantified in dry blood: silicon, chromium, lead, titanium, vanadium, nickel, arsenic, manganese, and cadmium. A total of 88 samples of anemic children and 208 of non-anemic children aged 6-12 years were analyzed. Lead (35.1%), chromium (24.3%), vanadium (24.3%), nickel (45.6%), and silicon (48.6%) were identified in the samples, with titanium only detected in anemic children. The average level of arsenic was higher in anemic than non-anemic children (0.041 ± 0.11 wt% vs 0.014 ± 0.05 wt%, p < 0.05) and correlated with the concentration of hemoglobin (r = -0.441, p < 0.01). In conclusion, heavy metals, which confer a health risk, were detected in the dry blood of the children evaluated, and the levels of arsenic and titanium were found to be related to anemia.

Hematological, biochemical, and toxicopathic effects of subchronic acetamiprid toxicity in Wistar rats

Acetamiprid is one of the most widely used neonicotinoids. This study investigates toxic effects of repeated oral administration of three doses of acetamiprid (1/20, 1/10, and 1/5 of LD₅₀) during 60 days. For this, male Wistar rats were divided into four different groups. Hematological, biochemical, and toxicopathic effects of acetamiprid were evaluated. According to the results, a significant decrease in the body weight gain at the highest dose 1/5 of LD₅₀ of acetamiprid was noticed. An increase in the relative liver weight was also observed at this dose level. The hematological constituents were affected. A significant decrease in RBC, HGB, and HCT in rats treated with higher doses of acetamiprid (1/10 and 1/5 of LD₅₀) was noted. However, a significant increase in WBC and PLT were observed at the same doses. Furthermore, acetamiprid induced liver toxicity measured by the increased activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphates (ALPs), and lactate dehydrogenase (LDH) which may be due to the loss of hepatic membrane architecture and hepatocellular damage. In addition, exposure to acetamiprid resulted in a significant decrease in the levels of superoxide dismutase and catalase activities (p ≤ 0.01) with concomitant increase in lipid peroxidation in rat liver. These findings highlight the subchronic hepatotoxicity of acetamiprid.

Titanium dioxide food additive (E171) induces ROS formation and genotoxicity: contribution of micro and nano-sized fractions

Since 1969, the European Union approves food-grade titanium dioxide (TiO₂), also known as E171 colouring food additive. E171 is a mixture of micro-sized particles (MPs) and nano-sized particles (NPs). Previous studies have indicated adverse effects of oral exposure to E171, i.e. facilitation of colon tumour growth. This could potentially be partially mediated by the capacity to induce reactive oxygen species (ROS). The aim of the present study is to determine whether E171 exposure induces ROS formation and DNA damage in an in vitro model using human Caco-2 and HCT116 cells and to investigate the contribution of the separate MPs and NPs TiO₂ fractions to these effects. After suspension of the particles in Hanks' balanced salt solution buffer and cell culture medium with either bovine serum albumin (BSA) or foetal bovine serum, characterization of the particles was performed by dynamic light scattering, ROS formation was determined by electron spin/paramagnetic resonance spectroscopy and DNA damage was determined by the comet and micronucleus assays. The results showed that E171, MPs and NPs are stable in cell culture medium with 0.05% BSA. The capacity for ROS generation in a cell-free environment was highest for E171, followed by NPs and MPs. Only MPs were capable to induce ROS formation in exposed Caco-2 cells. E171, MPs and NPs all induced single-strand DNA breaks. Chromosome damage was shown to be induced by E171, as tested with the micronucleus assay in HCT116 cells. In conclusion, E171 has the capability to induce ROS formation in a cell-free environment and E171, MPs and NPs have genotoxic potential. The capacity of E171 to induce ROS formation and DNA damage raises concerns about potential adverse effects associated with E171 (TiO₂) in food.

The effect of titanium dioxide nanoparticles on neuroinflammation response in rat brain

Titanium dioxide nanoparticles (TiO₂ NPs) are widely used for their whiteness and opacity in several applications such as food colorants, drug additives, biomedical ceramic, and implanted biomaterials. Research on the neurobiological response to orally administered TiO₂ NPs is still limited. In our study, we investigate the effects of anatase TiO₂ NPs on the brain of Wistar rats after oral intake. After daily intragastric administration of anatase TiO₂ NPs (5-10 nm) at 0, 50, 100, and 200 mg/kg body weight (BW) for 60 days, the coefficient of the brain, acethylcholinesterase (AChE) activities, the level of interleukin 6 (IL-6), and the expression of glial fibrillary acidic protein (GFAP) were assessed to quantify the brain damage. The results showed that high-dose anatase TiO₂ NPs could induce a downregulated level of AChE activities and showed an increase in plasmatic IL-6 level as compared to the control group accompanied by a dose-dependent decrease inter-doses, associated to an increase in the cerebral IL-6 level as a response to a local inflammation in brain. Furthermore, we observed elevated levels of immunoreactivity to GFAP in rat cerebral cortex. We concluded that oral intake of anatase TiO₂ NPs can induce neuroinflammation and could be neurotoxic and hazardous to health.

Circadian variation of cytotoxicity and genotoxicity induced by an immunosuppressive agent "Mycophenolate Mofetil" in rats

Immunosuppressive drugs such as Mycophenolate Mofetil (MMF) are used to suppress the immune system activity in transplant patients and reduce the risk of organ rejection. The present study investigates whether the potential cytotoxicity and genotoxicity varied according to MMF dosing-time in Wistar Rat. A potentially toxic MMF dose (300 mg/kg) was acutely administered by the i.p. route in rats at four different circadian stages (1, 7, 13 and 19 hours after light onset, HALO). Rats were sacrificed 3 days following injection, blood and bone marrow were removed for determination of cytotoxicity and genotoxicity analysis. The genotoxic effect of this pro-drug was investigated using the comet assay and the micronucleus test. Hematological changes were also evaluated according to circadian dosing time. MMF treatment induced a significant decrease at 7 HALO in red blood cells, in the hemoglobin rate and in white blood cells. These parameters followed a circadian rhythm in controls or in treated rats with an acrophase located at the end of the light-rest phase. A significant, thrombocytopenia was observed according to MMF circadian dosing time. Furthermore, abnormally shaped red cells, sometimes containing micronuclei, poikilocytotic in red cells and hypersegmented neutrophil nuclei were observed with MMF treatment. The micronucleus test revealed damage to chromosomes in rat bone marrow; the comet assay showed significant DNA damage. This damage varied according to circadian MMF dosing time. The injection of MMF in the middle of the dark-activity phase produced a very mild hematological toxicity and low genotoxicity. Conversely, it induced maximum hematological toxicity and genotoxicity when the administration occurred in the middle of the light-rest phase, which is physiologically analogous to the end of the activity of the diurnal phase in human patients.