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

The Nephroprotective Effect of In Utero Administration of Green Synthesized Titanium Dioxide Nanoparticles in Albino Rats

Titanium dioxide nanoparticles (TiO2-NPs) are one of the most popular nanoscale materials and have a wide range of applications in the manufacturing industry; nonetheless, researchers' focus has been directed to the detrimental consequences of TiO2-NPs. The current study was designed to assess the potential hazardous effects of chemically synthesized TiO2-NPs on the placenta and feto-maternal kidneys of rats. On the other hand, the probable positive impact of TiO2-NPs made after green synthesis was also evaluated. HepG2 cell lines were used to assess the cytotoxicity of chemical and green TiO2-NPs. Five groups of fifty pregnant female rats were formed (n=10). The first (control) group received distilled water. The second and third groups were orally given 100 and 300 mg/kg body weight (bw) of chemical TiO2-NPs, respectively. The fourth and fifth groups were orally given 100 and 300 mg/kg bw of green synthesized TiO2-NPs, respectively. On gestational day 20 (GD 20), blood and tissues were collected for biochemical and histological studies. Our findings revealed that chemical TiO2-NPs induced apoptosis in HepG2 cells at high concentrations, while there was no observed toxicity for green TiO2-NPs. The chemically treated TiO2-NPs groups showed a significant decrease in the level of HDL and a significant increase in cholesterol, LDL-cholesterol, and triglyceride levels. Renal tissues showed necrosis with exfoliation of lining epithelial cells, degenerated tubules, and glomerulonephritis. While the placenta was atrophied and hyalinized. Moreover, Bax expression significantly increased in the renal tubular cells and the villi of the placenta. Contrariwise, green TiO2-NPs-treated groups showed a significant rise in HDL levels with a significant reduction in triglycerides and LDL levels, while cholesterol levels were unaffected. Also, renal tissues showed mild degenerative changes in the glomeruli and renal tubules; thus, noticeable regeneration of epithelium lining tubules was detected in the maternal kidney. Bax showed a minimal reaction in the renal tubules and the villi of the placenta. It concluded that in contrast to chemical TiO2-NPs, biosynthesized TiO2-NPs with garlic showed a positive impact on the biochemical profile and histological investigations.

Oral toxicological study of titanium dioxide nanoparticles with a crystallite diameter of 6 nm in rats

BACKGROUND

Though titanium dioxide (TiO₂) is generally considered to have a low impact in the human body, the safety of TiO₂ containing nanosized particles (NPs) has attracted attention. We found that the toxicity of silver NPs markedly varied depending on their particle size, as silver NPs with a diameter of 10 nm exhibited fatal toxicity in female BALB/c mice, unlike those with diameters of 60 and 100 nm. Therefore, the toxicological effects of the smallest available TiO₂ NPs with a crystallite size of 6 nm were examined in male and female F344/DuCrlCrlj rats by repeated oral administration of 10, 100, and 1000 mg/kg bw/day (5/sex/group) for 28 days and of 100, 300, and 1000 mg/kg bw/day (10/sex/group) for 90 days.

RESULTS

In both 28- and 90-day studies, no mortality was observed in any group, and no treatment-related adverse effects were observed in body weight, urinalysis, hematology, serum biochemistry, or organ weight. Histopathological examination revealed TiO₂ particles as depositions of yellowish-brown material. The particles observed in the gastrointestinal lumen were also found in the nasal cavity, epithelium, and stromal tissue in the 28-day study. In addition, they were observed in Peyer's patches in the ileum, cervical lymph nodes, mediastinal lymph nodes, bronchus-associated lymphoid tissue, and trachea in the 90-day study. Notably, no adverse biological responses, such as inflammation or tissue injury, were observed around the deposits. Titanium concentration analysis in the liver, kidneys, and spleen revealed that TiO₂ NPs were barely absorbed and accumulated in these tissues. Immunohistochemical analysis of colonic crypts showed no extension of the proliferative cell zone or preneoplastic cytoplasmic/nuclear translocation of β-catenin either in the male or female 1000 mg/kg bw/day group. Regarding genotoxicity, no significant increase in micronucleated or γ-H2AX positive hepatocytes was observed. Additionally, the induction of γ-H2AX was not observed at the deposition sites of yellowish-brown materials.

CONCLUSIONS

No effects were observed after repeated oral administration of TiO₂ with a crystallite size of 6 nm at up to 1000 mg/kg bw/day regarding general toxicity, accumulation of titanium in the liver, kidneys, and spleen, abnormality of colonic crypts, and induction of DNA strand breaks and chromosomal aberrations.

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).

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.

An Overview of the Beneficial Role of Antioxidants in the Treatment of Nanoparticle-Induced Toxicities

Nanoparticles (NPs) are used in many products and materials for humans such as electronics, in medicine for drug delivery, as biosensors, in biotechnology, and in agriculture, as ingredients in cosmetics and food supplements. Besides that, NPs may display potentially hazardous properties on human health and the environment as a consequence of their abundant use in life nowadays. Hence, there is increased interest of researchers to provide possible therapeutic agents or dietary supplements for the amelioration of NP-induced toxicity. This review summarizes the new findings in the research of the use of antioxidants as supplements for the prevention and alleviation of harmful effects caused by exposure of organisms to NPs. Also, mechanisms involved in the formation of NP-induced oxidative stress and protective mechanisms using different antioxidant substances have also been elaborated. This review also highlights the potential of naturally occurring antioxidants for the enhancement of the antioxidant defense systems in the prevention and mitigation of organism damage caused by NP-induced oxidative stress. Based on the presented results of the most recent studies, it may be concluded that the role of antioxidants in the prevention and treatment of nanoparticle-induced toxicity is unimpeachable. This is particularly important in terms of oxidative stress suppression.

An Overview of the Beneficial Role of Antioxidants in the Treatment of Nanoparticle-Induced Toxicities

Nanoparticles (NPs) are used in many products and materials for humans such as electronics, in medicine for drug delivery, as biosensors, in biotechnology, and in agriculture, as ingredients in cosmetics and food supplements. Besides that, NPs may display potentially hazardous properties on human health and the environment as a consequence of their abundant use in life nowadays. Hence, there is increased interest of researchers to provide possible therapeutic agents or dietary supplements for the amelioration of NP-induced toxicity. This review summarizes the new findings in the research of the use of antioxidants as supplements for the prevention and alleviation of harmful effects caused by exposure of organisms to NPs. Also, mechanisms involved in the formation of NP-induced oxidative stress and protective mechanisms using different antioxidant substances have also been elaborated. This review also highlights the potential of naturally occurring antioxidants for the enhancement of the antioxidant defense systems in the prevention and mitigation of organism damage caused by NP-induced oxidative stress. Based on the presented results of the most recent studies, it may be concluded that the role of antioxidants in the prevention and treatment of nanoparticle-induced toxicity is unimpeachable. This is particularly important in terms of oxidative stress suppression.

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.

An updated review of protective effects of rosemary and its active constituents against natural and chemical toxicities

Natural and chemical toxic agents cause severe adverse effects on people's health in a variety of exposing ways. Herbal medications have taken into consideration as alternative safe treatments for toxicities. Rosmarinus officinalis also known as rosemary belongs to the Lamiaceae family. Rosemary and its constituents including carnosic acid, rosmarinic acid, and carnosol have a lot of benefits such as anti-inflammatory, antioxidant, anti-mutagenic, anti-bacterial, antiviral, antinociceptive, and neuroprotective activities. In this literate review, we focused on the protective effects of rosemary and its main compounds against natural and chemical toxicities in both in vitro and in vivo studies. The protective effects of rosemary and its components are mostly mediated through different mechanisms such as the inhibition of oxidative stress, reduction of inflammatory mediators including tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interleukin-17 (IL-17), cyclooxygenase-2 (COX-2) and nuclear factor ĸB (NF-ĸB) as well as the modulation of apoptosis and mitogen-activated protein kinase (MAPK) signaling pathways.

Oxidative Damage Induced by Nano-titanium Dioxide in Rats and Mice: a Systematic Review and Meta-analysis

Nano-titanium dioxide is a kind of widely used nanomaterial that exhibits various adverse outcomes. However, the role of oxidative stress in this regard remains controversial. This study aimed to evaluate whether oxidative stress is one of the toxicity mechanisms induced by nano-titanium dioxide in rats and mice model. In this meta-analysis, 64 relevant publications were included through detailed database search. The pooled results showed that nano-titanium dioxide exposure could promote the expression of oxidants, such as malonaldehyde (MDA), 8-hydroxy-2-deoxyguanosine (8-OHdG), superoxide anion (O₂^-), and hydrogen peroxide (H₂O₂). Meanwhile, the levels of antioxidant-related enzymes and molecules, such as superoxide dismutase (SOD), glutathione (GSH), glutathione peroxidase (GPx), and catalase (CAT), were reduced. Subgroup analysis revealed that different intervention routes, exposure periods, exposure dosages, and sample sources could affect the oxidative stress when exposed to nano-titanium dioxide. It was worth noting that the levels of MDA, 8-OHdG, and GSH significantly increased (P < 0.05) when the particle size of nano-titanium dioxide was < 10 nm, whereas H₂O₂, SOD, and GPx showed the highest effect at 10-40 nm. This study indicated that nano-titanium dioxide could cause oxidative damage by affecting the levels of enzymes and molecules involved in oxidative stress in rats and mice. And these results could provide a reference for studies of the toxicity mechanism induced by nano-titanium dioxide in the future.

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.