Toxicological interactions of silver nanoparticles and organochlorine pesticides in mouse peritoneal macrophages

Association between Organochlorine Pesticides and Vitamin D in Female Subjects

In human population studies, organochlorine pesticides (OCPs) have been linked to vitamin D deficiency. Therefore, this study examined the association between OCPs, vitamin D₃ (cholecalciferol, 25(OH)D₃), and the active metabolite 1,25-dihydrovitamin D₃ (1,25(OH)₂D₃) in a cohort of non-obese women. The serum samples of 58 female participants (age-31.9 ± 4.6 years; body mass index (BMI)-25.7 ± 3.7 kg/m²) were screened for 10 indicator OCPs. 25(OH)D₃ and 1,25(OH)₂D₃ levels were determined via isotope dilution liquid chromatography tandem mass spectrometry. In this cohort, the 25(OH)D₃ and 1,25(OH)₂D₃ levels were 22.9 ± 11.2 ng/mL and 0.05 ± 0.02 ng/mL, respectively, with 28 participants classified as 25(OH)D₃-deficient (<50 nmol/L). In the study cohort, no correlations were found between individual or total OCPs (ƩOCPs) and 25(OH)D₃. p,p'-dichlorodiphenyldichloroethylene (DDE) and ƩOCPs correlated positively with 1,25(OH)₂D₃, with the latter being negatively correlated with estimated glomerular filtration rate (eGFR). In women with sufficient 25(OH)D₃ levels, p,p'-dichlorodiphenyltrichloroethan (DDT) was positively correlated with 1,25(OH)₂D₃, whilst in the deficient group, hexachlorobenzene (HCB) and p,p'-(DDE) were positively correlated with 1,25(OH)₂D₃, β-Hexachlorocyclohexane (HCH) was positively correlated with 25(OH)D₃, and none of the OCPs were associated with measures of renal function. Overall, OCPs and ƩOCPs were not associated with 25(OH)D₃, suggesting that they are unrelated to vitamin D deficiency, but p,p'-DDE and ƩOCPs correlated positively with active 1,25(OH)₂D₃, while ƩOCPs correlated negatively with eGFR, suggesting a possible renal effect. Analysis of vitamin D deficiency revealed an association between β-HCH and 25(OH)D₃, and between HCB and p,p'-DDE and 1,25(OH)₂D₃, suggesting that OCP effects may be enhanced in cases of vitamin D deficiency.

Oxidative damage induced by combined exposure of titanium dioxide nanoparticles and cypermethrin in rats for 90 days

Titanium dioxide nanoparticles (TiO₂NPs) and cypermethrin (CPM) are widely used in various fields, and they can enter the environment in different ways. Combined exposure of TiO₂NPs and CPM may increase the accumulation of pollutants in organisms and affect human health. This study was undertaken to evaluate the oxidative and inflammatory parameters associated with the combined exposure of TiO₂NPs and CPM in rats. Twenty-four healthy male adult SD rats were randomly divided into four groups. The first group served as the control, while groups 2, 3, and 4 were treated with TiO₂NPs (450 mg/m³); CPM (6.67 mg/m³) or combined exposure of TiO₂NPs and CPM by inhalation for 90 days. We investigated the oxidative damage induced through combined exposure of TiO₂NPs and CPM in rats by evaluating hematology of the rats and determining the blood biochemical index. Our results demonstrated that inhalation of TiO₂NPs and CPM increased the levels of oxidative stress markers such as malondialdehyde and alkaline phosphatase in the serum of rats. These were accompanied by a decreased glutathione peroxidase and total superoxide dismutase levels. Furthermore, the level of glutathione peroxidase was further decreased while malondialdehyde was increased in the combined exposure of TiO₂NPs and CPM. Interestingly, pathological sections showed that different degrees of tissue injury could be seen in the liver and lung tissues of each exposure group. In summary, the combined exposure of TiO₂NPs and CPM can cause increased oxidative damage in rats and damage the tissue structure of the liver and lung.

Toxicological effects of silver nanoparticles and cadmium chloride in macrophage cell line (RAW 264.7): An in vitro approach

BACKGROUND

Silver nanoparticles (AgNP) are largely used in nanotechnological products, but the real risks for human and environment are still poorly understood if we consider the effects of mixtures of AgNP and environmental contaminants, such as non-essential metals.

METHODS

The aim of the present study was to investigate the cytotoxicity and toxicological interaction of AgNP (1-4 nm, 0.36 and 3.6 μg mL^-1) and cadmium (Cd, 1 and 10 μM) mixtures. The murine macrophage cell line RAW 264.7 was used as a model.

RESULTS

Effects were observed after a few hours (4 h) on reactive oxygen species (ROS) and became more pronounced after 24 h-exposure. Cell death occurred by apoptosis, and loss of cell viability (24 h-exposure) was preceded by increases of ROS levels and DNA repair foci, but not of NO levels. Co-exposure potentiated some effects (decrease of cell viability and increase of ROS and NO levels), indicating toxicological interaction.

CONCLUSION

These effects are important findings that must be better investigated, since the interaction of Cd with AgNP from nanoproducts may impair the function of macrophages and represent a health risk for humans.

The effects of autophagy in rat tracheal epithelial cells induced by silver nanoparticles

The massive use of silver nanoparticles (AgNPs) is potentially harmful to exposed humans. Although previous studies have found that AgNPs can induce cell autophagy, few studies have focused on the toxic pathways and mechanisms of autophagy induced by AgNPs in rat respiratory epithelial (RTE) cells. In this study, RTE cells were exposed to two kinds of AgNPs in vitro to ascertain the influence of mTOR-autophagy pathway-associated protein expression, including Beclin1, LC3B, Atg5, and Atg7. After exposure to different sizes and concentrations of AgNPs for 12 h, the uptake of silver in RTE cells reached 0.45 μg/L to 1.11 μg/L, indicating that AgNPs can enter RTE cells, leading to toxic effects. Our study found that this toxic effect was related to autophagy caused by ROS accumulation that was mediated by the mTOR pathway. With increasing AgNP exposure concentrations, the expression of p-mTOR was significantly downregulated, and expression of the autophagy-related proteins Beclin1, LC3B, Atg5, and Atg7 was significantly increased in RTE cells in all exposed groups. At a concentration of 1000 μg/L, the expression of LC3BII/LC3BI in all exposed groups was 24.49 times and 12.71 times that of the control, and the expression of Atg7 in all exposed groups was 23.21 times and 13.21 times that of the control. The upregulation of autophagy-related proteins in the AgNP-10 nm exposure groups was greater than that of the AgNP-100 nm exposure group. In summary, the mTOR pathway mediates AgNP-induced autophagy in RTE cells, which leads to damage to the respiratory system barrier and human health risks. This study can facilitate the development of prevention and intervention policies against adverse consequences induced by AgNPs.

Endophytic Nanotechnology: An Approach to Study Scope and Potential Applications

Nanotechnology has become a very advanced and popular form of technology with huge potentials. Nanotechnology has been very well explored in the fields of electronics, automobiles, construction, medicine, and cosmetics, but the exploration of nanotecnology's use in agriculture is still limited. Due to climate change, each year around 40% of crops face abiotic and biotic stress; with the global demand for food increasing, nanotechnology is seen as the best method to mitigate challenges in disease management in crops by reducing the use of chemical inputs such as herbicides, pesticides, and fungicides. The use of these toxic chemicals is potentially harmful to humans and the environment. Therefore, using NPs as fungicides/ bactericides or as nanofertilizers, due to their small size and high surface area with high reactivity, reduces the problems in plant disease management. There are several methods that have been used to synthesize NPs, such as physical and chemical methods. Specially, we need ecofriendly and nontoxic methods for the synthesis of NPs. Some biological organisms like plants, algae, yeast, bacteria, actinomycetes, and fungi have emerged as superlative candidates for the biological synthesis of NPs (also considered as green synthesis). Among these biological methods, endophytic microorganisms have been widely used to synthesize NPs with low metallic ions, which opens a new possibility on the edge of biological nanotechnology. In this review, we will have discussed the different methods of synthesis of NPs, such as top-down, bottom-up, and green synthesis (specially including endophytic microorganisms) methods, their mechanisms, different forms of NPs, such as magnesium oxide nanoparticles (MgO-NPs), copper nanoparticles (Cu-NPs), chitosan nanoparticles (CS-NPs), β-d-glucan nanoparticles (GNPs), and engineered nanoparticles (quantum dots, metalloids, nonmetals, carbon nanomaterials, dendrimers, and liposomes), and their molecular approaches in various aspects. At the molecular level, nanoparticles, such as mesoporous silica nanoparticles (MSN) and RNA-interference molecules, can also be used as molecular tools to carry genetic material during genetic engineering of plants. In plant disease management, NPs can be used as biosensors to diagnose the disease.

Status Quo in Data Availability and Predictive Models of Nano-Mixture Toxicity

Co-exposure of nanomaterials and chemicals can cause mixture toxicity effects to living organisms. Predictive models might help to reduce the intensive laboratory experiments required for determining the toxicity of the mixtures. Previously, concentration addition (CA), independent action (IA), and quantitative structure–activity relationship (QSAR)-based models were successfully applied to mixtures of organic chemicals. However, there were few studies concerning predictive models for toxicity of nano-mixtures before June 2020. Previous reviews provided comprehensive knowledge of computational models and mechanisms for chemical mixture toxicity. There is a gap in the reviewing of datasets and predictive models, which might cause obstacles in the toxicity assessment of nano-mixtures by using in silico approach. In this review, we collected 183 studies of nano-mixture toxicity and curated data to investigate the current data and model availability and gap and to derive research challenges to facilitate further experimental studies for data gap filling and the development of predictive models.

Adverse effects of pesticides on the functions of immune system

Pesticides are chemical substances used to kill unwanted fungi, weeds and insects. In many countries, there is currently concern regarding the adverse effects of pesticides on health. It has been reported that pesticides may cause cancer, respiratory diseases, organ diseases, system failures, nervous system disorders and asthma, which are closely connected with immune disorders. Therefore, this study reviewed the immunotoxicity of pesticides that are currently used or prohibited from being used, especially their effects on leukocytes such as T cells, B cells, NK cells and macrophages. These immune cells play crucial roles in innate and adaptive immune systems to protect hosts. Pesticides are known to have possible toxicological modes of action to induce oxidative stress, mitochondrial dysfunction, and endoplasmic reticulum (ER) stress in living organisms. According to previous studies, pesticides such as atrazine (ATR), organophophorus (OP) compounds, carbamates, and pyrethroids were shown to inhibit the survival and growth of leukocytes by inducing apoptosis or cell cycle arrest and interfering with the specific immunological functions of each type of immune cells. These results suggest the immunotoxicity of pesticides toward specific immune cells. To substantiate the overall immunocompromised effects of pesticides, there is a need to collect and thoroughly analyze additional information regarding other immunological toxicities.

Nanotechnology for Plant Disease Management

Each year, 20%–40% of crops are lost due to plant pests and pathogens. Existing plant disease management relies predominantly on toxic pesticides that are potentially harmful to humans and the environment. Nanotechnology can offer advantages to pesticides, like reducing toxicity, improving the shelf-life, and increasing the solubility of poorly water-soluble pesticides, all of which could have positive environmental impacts. This review explores the two directions in which nanoparticles can be utilized for plant disease management: either as nanoparticles alone, acting as protectants; or as nanocarriers for insecticides, fungicides, herbicides, and RNA-interference molecules. Despite the several potential advantages associated with the use of nanoparticles, not many nanoparticle-based products have been commercialized for agricultural application. The scarcity of commercial applications could be explained by several factors, such as an insufficient number of field trials and underutilization of pest–crop host systems. In other industries, nanotechnology has progressed rapidly, and the only way to keep up with this advancement for agricultural applications is by understanding the fundamental questions of the research and addressing the scientific gaps to provide a rational and facilitate the development of commercial nanoproducts.

Responses of human hepatoma HepG2 cells to silver nanoparticles and polycyclic aromatic hydrocarbons

The nanotechnology has revolutionized the global market with silver nanoparticles (AgNP) occupying a prominent position due to their remarkable anti-bacterial properties. However, there is no data about the adverse and toxic effects of associations of AgNP and ubiquitous compounds, such as polycyclic aromatic hydrocarbons (PAH). In the current study, we investigated the responses of HepG2 cells to realistic concentrations of AgNP (0.09, 0.9, and 9 ng ml^-1) and mixture of PAH (30 and 300 ng ml^-1), separately and in association. Cell viability and cytotoxicity (neutral red retention and MTT production assays) and proliferation (crystal violet [CV] assay), xenobiotic efflux transporter activity (rhodamine B accumulation assay), ROS levels (dichlorodihydrofluorescein diacetate assay), and lipid peroxidation (pyrenylphosphine-1-diphenyl assay) were analyzed. There was no decreases of cell viability after exposure to AgNP, PAH and most of AgNP + PAH associations, but increases of cell viability/number (CV assay) occurred. Efflux transporter activity was not affected, with exception of one AgNP + PAH associations, ROS levels increased, but lipid peroxidation decreased. Some toxicological interactions occurred, particularly for the highest concentrations of AgNP and PAH, but there is no evidence that these interactions increased the toxicity of AgNP and PAH.