Toxicity of silver nanoparticles on the brain of Oreochromis niloticus and Tilapia zillii

Tire Rubber Based Microplastic Particles Cause Adverse on Quality Parameters of Rainbow Trout Sperm Cells

In the present study, we aimed to determine the parameters of oxidative stress markers, motility and kinematics of rainbow trout (Oncorhynchus mykiss) sperm cells exposed to different doses (0.001, 0.01, 0.1, 1.0, and 10 mg/L, in vitro 4 h) of tire rubber based microplastic particles (TRMP-Ps) the leachates procedure of rubber pieces. First of all, TRMP-Ps were prepared by abrasion method in accordance with the literature. Structural and morphological features of TRMP-Ps were determined by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) methods, respectively. Energy dispersive X-ray (EDX) analysis technique was used to characterize the elemental composition of TRMP-Ps. Particle size of microplastic structures was measured hydrodynamically with dynamic light scattering analysis (DLS). After exposure, the effect of TRMP-Ps was defined by the observations of kinematics and antioxidant activities in sperm cells. Our findings showed that the straight line velocity, the curvilinear velocity, the angular path velocity, and the amplitude of lateral displacement of sperm cells decreased. Moreover, while the level of superoxide dismutase decreased dose-dependently against the toxicity of TRMP-Ps, no significant change was observed in the levels of malondialdehyde and total glutathione. The 4-h median effective concentrations (EC50) of TRMP-Ps based on mobility parameters of sperm ranged from 0.31 mg/L for reduced straight line velocity of sperm cells to 0.51 mg/L for reduced amplitude of lateral displacement of the spermatozoa head. Therefore, we concluded that TRMP-Ps can be a risk for the reproduction cycle of fish in aquatic environments.

Behavioural changes, DNA damage and histological alterations in Labeo rohita fingerlings in response to organic-coated silver nanoparticles

Silver nanoparticles (AgNPs) have garnered significant global attention from researchers due to their unique physicochemical properties and wide-ranging applications in industry and medicine. However, their release into aquatic ecosystems has raised concerns regarding potential ecotoxicological consequences. The present study investigated the effects of polyvinyl pyrrolidone-coated silver nanoparticles on Labeo rohita fingerlings, focusing on behavioural reactions, genotoxic effects, histological changes and bioaccumulation. L. rohita fingerlings were exposed to polyvinyl pyrrolidone-coated silver nanoparticles with sizes ranging from 18 to 29 nm for 7 days at concentrations of 100, 200, 400 and 800 ug/l. The nanoparticle zeta potential was found to be extremely negative, measuring - 55.5 mV for 18 nm and - 31.4 mV for 29 nm. Behavioural abnormalities, including respiratory distress, reduced responsiveness and erratic swimming, were observed in exposed groups compared to controls, with severity increasing with higher nanoparticle concentrations. Genotoxicity assessment revealed significantly higher DNA damage in kidney cells compared to gill cells. Histological examination of gill tissues showed clogging in primary and secondary lamellae, along with distorted anatomy, necrosis and vacuolar atrophy in peripheral tubules of the kidneys. The kidneys exhibited greater nanoparticle accumulation than the gills with prolonged exposure. Moreover, 18 nm AgNPs induced more pronounced DNA damage and histological alterations in the kidney and gill tissues compared to 29 nm nanoparticles. This study elucidates the critical role of monitoring AgNPs in aquatic systems, providing essential data on their behaviour and environmental impacts. The findings highlight the need for improved detection techniques and effective management of AgNP contamination. Future research should focus on developing more sensitive analytical methods, understanding long-term ecological effects and exploring innovative remediation strategies.

The effects of iron oxide nanoparticles on antioxidant capacity and response to oxidative stress in Mozambique tilapia (Oreochromis mossambicus, Peters 1852)

Recent research has raised concern about the biocompatibility of iron oxide nanoparticles (IONPs), as they have been reported to induce oxidative stress and inflammatory responses, whilst prolonged exposure to high IONP concentrations may lead to cyto-/genotoxicity. Besides, there is concern about its environmental impact. The aim of our study was to investigate the effects of IONPs on the antioxidant defence system in freshwater fish Mozambique tilapia (Oreochromis mossambicus, Peters 1852). The fish were exposed to IONP concentration of 15 mg/L over 1, 3, 4, 15, 30, and 60 days and the findings compared to a control, unexposed group. In addition, we followed up the fish for 60 days after exposure had stopped to estimate the stability of oxidative stress induced by IONPs. Exposure affected the activity of antioxidant and marker enzymes and increased the levels of hydrogen peroxide and lipid peroxidation in the gill, liver, and brain tissues of the fish. Even after 60 days of depuration, adverse effects remained, indicating long-term nanotoxicity. Moreover, IONPs accumulated in the gill, liver, and brain tissues. Our findings underscore the potential health risks posed to non-target organisms in the environment, and it is imperative to establish appropriate guidelines for safe handling and disposal of IONPs to protect the aquatic environment.

Neutralization of iron oxide magnetic nanoparticle aquatoxicity on Oncorhynchus mykiss via supplementation with ulexite

Nowadays, the unique features of nanoparticles (NPs) have encouraged new applications in different areas including biology, medicine, agriculture, and electronics. Their quick joining into daily life not only enhances the uses of NPs in a wide range of modern technologies but also their release into the aquatic environment causes inevitable environmental concerns. On the other hand boron exhibits key physiological effects on biological systems. This research was designed for evaluating the toxicity of magnetite nanoparticles (Fe3O4-MNPs) on aquatic organisms and obtaining data for the information gap in this area. In this study, Rainbow trout (Oncorhynchus mykiss) was considered as an aquatic indicator, and trials were designed as Ulexite (a boron mineral, UX) treatment against exposure to Fe3O4-MNPs. Synthesized and characterized Fe3O4-MNPs were exposed to rainbow trouts in wide spectrum concentrations (0.005-0.08 mL/L) to analyze its lethal dose (LC50) and cytoprotective properties by UX treatment were assessed against Fe3O4-MNPs applications for 96 h. For the initial toxicity analysis, hematological parameters (blood cell counts) were examined in experimental groups and micronucleus (MN) assay was performed to monitor nuclear abnormalities after exposure to NPs. Biochemical analyzes in both blood and liver samples were utilized to assess antioxidant/oxidative stress and inflammatory parameters. Also, 8-hydroxy-2'-deoxyguanosine (8-OHdG) assay was used to investigate oxidative DNA lesions and Caspase-3 analysis was performed on both blood and liver tissues to monitor apoptotic cell death occurrence. When antioxidant enzymes in blood and liver tissue were examined, time-dependent decreases in activity were determined in SOD, CAT, GPx, and GSH enzymes, while increased levels of MDA and MPO parameters were observed in respect to Fe3O4-MNPs exposure. It was found that TNF-α, Il-6 levels were enhanced against Fe3O4-MNPs treatment, but Nrf-2 levels were decreased at the 46th and 96th h. In the 96th application results, all parameters were statistically significant (p < 0.05) in blood and liver tissue, except for the IL-6 results. It was determined that the frequency of MN, the level of 8-OHdG and caspase-3 activity increased in respect to Fe3O4-MNPs exposure over time. Treatment with UX alleviated Fe3O4-MNPs-induced hematotoxic and hepatotoxic alterations as well as oxidative and genetic damages. Our findings offer strong evidence for the use of UX as promising, safe and natural protective agents against environmental toxicity of magnetite nanoparticles.

Determination of dose- and time-dependent hepatotoxicity and apoptosis of Lanthanum oxide nanoparticles in female Swiss albino mice

Nanosized lanthanum oxide particles (La2O3) are commonly utilized in various industries. The potential health risks associated with La2O3 nanoparticles, cytotoxic effects at varying doses and time intervals, and the mechanisms behind their induction of behavioral changes remain uncertain and necessitate further investigation. Therefore, this study examined in vivo hepatotoxicity, considering the quantity (60, 150, and 300 mg/kg) and time-dependent induction of reactive oxygen species (ROS) over one week or 21 days. The mice received intraperitoneal injections of three different concentrations in Milli-Q water. Throughout the experiments, no physical changes or weight loss were observed among the groups. However, after 21 days, only the highest concentration showed signs of anxiety in the activity cage (p < 0.05). Subsequently, all animals treated with La2O3 NPs exhibited a significant loss of learning and memory recall using the Active Avoidances test, after 21 days (p < 0.001). Markers for anti-reactive oxygen species (ROS) such as superoxide dismutase (SOD) were significantly upregulated in response to all concentrations of NPs after seven days compared to the control group. This was confirmed by a significant increase in glutathione peroxidase (Gpx1) and pro-apoptotic Caspase-3 expression at the lowest and highest doses. Additionally, both transcription and protein levels of the anti-apoptotic BCL-2 surpassed P53 protein in a dosage-dependent manner, indicating activation of the primary anti-apoptosis pathway. After 21 days, P53 levels exceeded BCL-2 protein levels, confirming a significant loss of BCL-2 mRNA, particularly at the 300 mg/kg concentration. Furthermore, a higher transcription level of Caspase-3, SOD, and Gpx1 was observed, with the highest values detected at the 300 mg/kg concentration, indicating the activation of cell death. Histopathological analysis of the liver illustrated apoptotic bodies resulting from La2O3 NP concentration. The investigation revealed multiple inflammatory foci, cytoplasmic degeneration, steatosis, and DNA fragmentation consistent with increased damage over time due to higher concentrations. Blood samples were also analyzed to determine liver enzymatic changes, including alkaline phosphatase (ALP), alanine transaminase (ALT), aspartate aminotransferase (AST), and lipid profiles. The results showed significant differences among all La2O3 NP concentrations, with the most pronounced damage observed at the 300 mg/kg dose even after 21 days. Based on an animal model, this study suggests that La2O3 hepatotoxicity is likely caused by the size and shape of nanoparticles (NPs), following a dose and time-dependent mechanism that induces the production of reactive oxygen species and behavioral changes such as anxiety and memory loss.

ZIF-8 Nanoparticles Induce Behavior Abnormality and Brain Oxidative Stress in Adult Zebrafish (Danio rerio)

Zeolitic imidazolate framework-8 nanoparticles (ZIF-8 NPs) are typical metal-organic framework (MOF) materials and have been intensively studied for their potential application in drug delivery and environmental remediation. However, knowledge of their potential risks to health and the environment is still limited. Therefore, this study exposed female and male zebrafish to ZIF-8 NPs (0, 9.0, and 90 mg L^-1) for four days. Subsequently, variations in their behavioral traits and brain oxidative stress levels were investigated. The behavioral assay showed that ZIF-8 NPs at 90 mg/L could significantly decrease the locomotor activity (i.e., hypoactivity) of both genders. After a ball falling stimulation, zebrafish exposed to ZIF-8 NPs (9.0 and 90 mg L^-1) exhibited more freezing states (i.e., temporary cessations of movement), and males were more sensitive than females. Regardless of gender, ZIF-8 NPs exposure significantly reduced the SOD, CAT, and GST activities in the brain of zebrafish. Correlation analysis revealed that the brain oxidative stress induced by ZIF-8 NPs exposure might play an important role in their behavioral toxicity to zebrafish. These findings highlight the necessity for further assessment of the potential risks of MOF nanoparticles to aquatic species and the environment.

Endogenous enzymatic antioxidant status of whiteleg shrimp (Litopenaeus vannamei) following exposure to sublethal concentrations of silver nanoparticles

Immunotoxicity of silver nanoparticles (AgNPs) to whiteleg shrimp (Litopenaeus vannamei) was assessed using redox-status orchestrating enzymes. To this end, the shrimp was exposed to sublethal AgNPs concentrations (0 % LC₅₀: control; 25 % LC₅₀: 0.97 mg/L; 50 % LC₅₀: 1.95 mg/L; 75 % LC₅₀: 2.92 mg/L). During the experiment, the behavior of superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), and glutathione peroxidase (GPx) was monitored, besides total antioxidant capacity (TAC) and malondialdehyde (MDA). The hepatopancreas SOD activity reduced about 63 %-76 % at.%50 LC₅₀ and %75 LC₅₀ AgNPs treatments, and CAT decreased in both tissues at 50 % LC₅₀ AgNPs. TAC exhibited a U-form response in the hepatopancreas organ against stress caused by AgNPs, and hepatopancreas MDA displayed a time-dependent increase. Taken together, AgNPs triggered severe immunotoxicity through suppression of CAT, SOD, and TAC in the hepatopancreas tissue.

Effect of Quercetin Nanoparticles on Hepatic and Intestinal Enzymes and Stress-Related Genes in Nile Tilapia Fish Exposed to Silver Nanoparticles

Recently, nanotechnology has become an important research field involved in the improvement of animals' productivity, including aquaculture. In this field, silver nanoparticles (AgNPs) have gained interest as antibacterial, antiviral, and antifungal agents. On the other hand, their extensive use in other fields increased natural water pollution causing hazardous effects on aquatic organisms. Quercetin is a natural polyphenolic compound of many plants and vegetables, and it acts as a potent antioxidant and therapeutic agent in biological systems. The current study investigated the potential mitigative effect of quercetin nanoparticles (QNPs) against AgNPs-induced toxicity in Nile tilapia via investigating liver function markers, hepatic antioxidant status, apoptosis, and bioaccumulation of silver residues in hepatic tissue in addition to the whole-body chemical composition, hormonal assay, intestinal enzymes activity, and gut microbiota. Fish were grouped into: control fish, fish exposed to 1.98 mg L-1 AgNPs, fish that received 400 mg L-1 QNPs, and fish that received QNPs and AgNPs at the same concentrations. All groups were exposed for 60 days. The moisture and ash contents of the AgNP group were significantly higher than those of the other groups. In contrast, the crude lipid and protein decreased in the whole body. AgNPs significantly increased serum levels of ALT, AST, total cholesterol, and triglycerides and decreased glycogen and growth hormone (*** p < 0.001). The liver and intestinal enzymes' activities were significantly inhibited (*** p < 0.001), while the oxidative damage liver enzymes, intestinal bacterial and Aeromonas counts, and Ag residues in the liver were significantly increased (*** p < 0.001, and * p < 0.05). AgNPs also significantly upregulated the expression of hepatic Hsp70, caspase3, and p53 genes (* p < 0.05). These findings indicate the oxidative and hepatotoxic effects of AgNPs. QNPs enhanced and restored physiological parameters and health status under normal conditions and after exposure to AgNPs.

Accumulation, Chronicity, and Induction of Oxidative Stress Regulating Genes Through Allium cepa L. Functionalized Silver Nanoparticles in Freshwater Common Carp (Cyprinus carpio)

Green evolutionary products such as biologically fabricated nanoparticles (NPs) pose a hazard to aquatic creatures. Herein, biogenic silver nanoparticles (AgNPs) were synthesized by the reaction between ionic silver (AgNO₃) and aqueous onion peel extract (Allium cepa L). The synthesized biogenic AgNPs were characterized with UV-Visible spectrophotometer, XRD, FT-IR, and TEM with EDS analysis; then, their toxicity was assessed on common carp fish (Cyprinus carpio) using biomarkers of haematological alterations, oxidative stress, histological changes, differential gene expression patterns, and bioaccumulation. The 96 h lethal toxicity was analysed with various concentrations (2, 4, 6, 8, and 10 mg/l) of biogenic AgNPs. Based on 96 h LC₅₀, sublethal concentrations (1/15^th, 1/10^th, and 1/5^th) were given to C. carpio for 28 days. At the end of experiment, the bioaccumulations of Ag content were accumulated mainly in the gills, followed by the liver and muscle. At an interval of 7 days, the haematological alterations showed significance (p < 0.05) and elevation of antioxidant defence mechanism reveals the toxicity of biogenic synthesized AgNPs. Adverse effects on oxidative stress were probably related to the histopathological damage of its vital organs like gill, liver, and muscle. Finally, the fish treated with biogenic synthesized AgNPs were significantly (p < 0.05) downregulates the oxidative stress genes such as Cu-Zn SOD, CAT, GPx1a, GST-α, CYP1A, and Nrf-2 expression patterns. The present study provides evidence of biogenic synthesized AgNPs influence on the aquatic life through induction of oxidative stress.

The Cytotoxicity, DNA Fragmentation, and Decreasing Velocity Induced By Chromium(III) Oxide on Rainbow Trout Spermatozoa

The present study aimed to determine the cytotoxicity of chromium(III) oxide micro particles (Cr₂O₃-Ps) in rainbow trout (Oncorhynchus mykiss) spermatozoa. Firstly, Cr₂O₃-Ps were synthesized and structurally characterized the surface, morphological for particle size and thermal properties. In addition, its structural and elemental purity was determined using energy-dispersive X-ray (EDX) spectrum and elemental maps. Structural purity, thermal properties, and stability of Cr₂O₃-Ps were also examined in detail by performing thermal analysis techniques. The cytotoxicity of Cr₂O₃-Ps was measured by the observation of velocities, antioxidant activities, and DNA damages in rainbow trout spermatozoa after exposure during 3 h in vitro incubation. The straight line velocity (VSL), the curvilinear velocity (VCL), and the angular path velocity (VAP) of spermatozoa decreased after exposure to Cr₂O₃-Ps. While the superoxide dismutase (SOD) and the catalase (CAT) decreased, the lipid peroxidation increased in a dose-dependent manner. However, the total glutathione (tGSH) was not affected in this period. DNA damages were also determined in spermatozoa using Comet assay. According to DNA in tail (%) data, DNA damages have been detected with gradually increasing concentrations of Cr₂O₃-Ps. Furthermore, all of class types which are categorized as the intensity of DNA fragmentation has been observed between 50 and 500 µg/L concentrations of Cr₂O₃-Ps exposed to rainbow trout spermatozoa. At the end of this study, we determined that the effective concentrations (EC50) were 76.67 µg/L for VSL and 87.77 µg/L for VCL. Finally, these results about Cr₂O₃-Ps may say to be major risk concentrations over 70 µg/L for fish reproduction in aquatic environments.

Can high- and low-temperature thermal stress modulate the antioxidant defense response of Astyanax lacustris brain?

Change in temperature of aquatic environment have impacts on the physiology of fish, especially in the brain, which is a vital organ and prone to oxidative damage. Astyanax lacustris is a freshwater fish that play an important role in the food market and has been increasingly used in fish farms, besides environmental monitoring studies. Therefore, this study aimed to evaluate the responses of antioxidant biomarkers and products of the oxidative process in the brains A. lacustris subjected to thermal shock. The specimens were obtained from artificial farming lakes and subjected to shock induced by exposure to high (31 °C ± 0.5) and low (15 °C ± 0.5) temperature for 2, 6, 12, 24, 48, 72 and 96 h; control group were maintained at 23 °C ± 0.5. At 31 °C, glutathione-related enzymes were more responsive, suggested by the change activity of GPx and G6PDH enzymes, in addition to GSH levels. At 15 °C, enzymes of the first line of defense were more active, evidenced by the change CAT activity. No significant changes were detected in the levels of ROS, LPO and PCO. These results indicate that the brains of A. lacustris have an efficient antioxidant defense system with the ability to acclimatize to the temperatures tested.

FeMn with Phases of a Degradable Ag Alloy for Residue-Free and Adapted Bioresorbability

The development of bioresorbable materials for temporary implantation enables progress in medical technology. Iron (Fe)-based degradable materials are biocompatible and exhibit good mechanical properties, but their degradation rate is low. Aside from alloying with Manganese (Mn), the creation of phases with high electrochemical potential such as silver (Ag) phases to cause the anodic dissolution of FeMn is promising. However, to enable residue-free dissolution, the Ag needs to be modified. This concern is addressed, as FeMn modified with a degradable Ag-Calcium-Lanthanum (AgCaLa) alloy is investigated. The electrochemical properties and the degradation behavior are determined via a static immersion test. The local differences in electrochemical potential increase the degradation rate (low pH values), and the formation of gaps around the Ag phases (neutral pH values) demonstrates the benefit of the strategy. Nevertheless, the formation of corrosion-inhibiting layers avoids an increased degradation rate under a neutral pH value. The complete bioresorption of the material is possible since the phases of the degradable AgCaLa alloy dissolve after the FeMn matrix. Cell viability tests reveal biocompatibility, and the antibacterial activity of the degradation supernatant is observed. Thus, FeMn modified with degradable AgCaLa phases is promising as a bioresorbable material if corrosion-inhibiting layers can be diminished.

Antibiotic resistance in aquaculture and aquatic organisms: a review of current nanotechnology applications for sustainable management

Aquaculture has emerged as one of the world's fastest-growing food industries in recent years, helping food security and boosting global economic status. The indiscriminate disposal of untreated or improperly managed waste and effluents from different sources including production plants, food processing sectors, and healthcare sectors release various contaminants such as bioactive compounds and unmetabolized antibiotics, and antibiotic-resistant organisms into the environment. These emerging contaminants (ECs), especially antibiotics, have the potential to pollute the environment, particularly the aquatic ecosystem due to their widespread use in aquaculture, leading to various toxicological effects on aquatic organisms as well as long-term persistence in the environment. However, various forms of nanotechnology-based technologies are now being explored to assist other remediation technologies to boost productivity, efficiency, and sustainability. In this review, we critically highlighted several ecofriendly nanotechnological methods including nanodrug and vaccine delivery, nanoformulations, and nanosensor for their antimicrobial effects in aquaculture and aquatic organisms, potential public health risks associated with nanoparticles, and their mitigation measures for sustainable management.

Comparative toxicity of silver nanoparticles and silver nitrate in freshwater fish Oreochromis mossambicus: A multi-biomarker approach

Silver nanoparticles (AgNPs) in the aquatic environment affect ecological repercussions and have fatal impacts on aquatic animals. The current study examined and correlated the toxicity of silver nitrate (AgNO₃) and silver nanoparticles (AgNPs) to the Mozambique tilapia, Oreochromis mossambicus. The comparative toxicity studies were done by exposing O. mossambicus to various doses of AgNO₃ and AgNPs (0, 25, 50, 75, and 100 μg/L) over a 7-day subacute exposure period. AAS analysis was used to detect Ag accumulation, while the histological examination established gill tissue damage. Oxidative stress affects lipid peroxidation (LPO) and protein carbonyl activity (PCA) in the gill tissue. Antioxidant parameters such as glutathione-S-transferase (GST), glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase activity (CAT), and non-enzymatic antioxidants such as metallothionein (MT) and reduced glutathione. The serum in the blood was used to determine non-specific immunological characteristics such as lysozyme (LYZ), myeloperoxidase (MPO), and respiratory burst activity (RBA). The neurotoxic impact of acetylcholine esterase activity (AChE) was investigated in brain tissues. The findings demonstrated that larger concentrations of AgNO₃ than AgNPs improved enzymatic antioxidant activities in the gill tissue. Histological examination of fish gills demonstrated that both AgNPs and AgNO₃ induced telangiectasia and epithelial cell hyperplasia. By increasing the concentration of AgNPs and AgNO₃, the present research demonstrated that silver accumulation leads to inefficient oxidative stress and altered enzymatic and non-enzymatic parameters, leading to cellular damage.

Silver Nanoparticles Induce Time- and Tissue-Specific Genotoxicity in Oreochromis niloticus: Utilizing the Adsorptive Capacities of Fruit Peels to Minimize Genotoxicity

Fish were exposed to a sub-lethal concentration of silver nanoparticles with and without orange and banana peels water treatment for 24, 48, and 96 h. The adsorption of AgNPs on both peels was recognized by scanning electron microscopic, energy dispersive X-ray spectroscopy, and laser ablation imaging. The % of DNA damage in liver and muscle tissues (comet assay) showed significant elevations in all studied groups with the maximum level in liver tissues after 24 h. DNA damage was markedly decreased after 48, and 96 h signifying the presence of an effective repairing mechanism. Micronucleus and nine nuclear anomalies were recorded in the peripheral blood cells. All anomalies were observed in all studied groups with a maximum induction rate after 96 h. of exposure. Based on the % of DNA damage and the frequencies of nuclear anomalies, water treatment with orange and banana peel succeeded to reduce AgNPs-induced genotoxic damage.

Acute Exposure to Biogenic Nanosilver Produced from Fusarium oxysporum in a Neotropical Fish

Biogenic nanosilver (bNAg) has emerged as a potentially less toxic alternative to synthetic nanosilver. However, no studies have evaluated its effects on a fish species from the Neotropical region. Thus, our aim was to evaluate the effects of a bNAg on the Neotropical fish Prochilodus lineatus. For this purpose, after 24 h of exposure to 100 µg L^-1 of bNAg, blood samples were collected to evaluate hematological, genotoxic, and plasma parameters. Gills and liver were sampled to evaluate biomarkers of oxidative stress and brain samples were used to assess neurotoxicity. The fish presented hyperglycemia, an increased number of erythrocytes, a reduction in antioxidant enzyme activity in both tissues evaluated, and a decrease in lipid peroxidation in the gills. We concluded that P. lineatus is a sensitive species to this nanoparticle, since it presented alterations in several biomarkers after an acute exposure.

Modulatory effect of dietary copper nanoparticles and vitamin C supplementations on growth performance, hematological and immune parameters, oxidative status, histology, and disease resistance against Yersinia ruckeri in rainbow trout (Oncorhynchus mykiss)

Copper and vitamin C are micronutrients needed for the living organism's functions. Vitamin C has a great effect on the immune system of fish. The present study aimed to evaluate the effects of dietary copper nanoparticles (Cu-NPs) and vitamin C (VC) supplementations on rainbow trout (Oncorhynchus mykiss) juveniles. So, 216 rainbow trout juveniles were randomly assigned to six groups with trial diets supplemented with Cu-NPs and VC including 0/0 (T1, control diet), 0/250 (T2), 0/500 (T3), 2/250 (T4), 2/500 (T5), and 2/0 (T6) mg Cu-NPs/VC per kg diet. After the feeding trial for 60 days, the fish were challenged with Yersinia ruckeri, and the survival rate was calculated for 15 days. Based on the data analysis, weight gain (WG), specific growth rate (SGR), protein efficiency ratio (PER), lysozyme, alternative complement activity (ACH50), hematocrit (Hct), hemoglobin (Hb), and mean corpuscular volume (MCV) were significantly (p < 0.05) increased in the fish fed on T4 and T5 diets compared with the control group. Catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPX) were significantly (p < 0.05) decreased in the fish fed with diets contain Cu-NPs and VC (T4 and T5). The expressions of TNF-α, IL-1ß, IL-10, SOD, CAT, and GPX genes were significantly (p < 0.05) decreased in the fish fed on T3, T4, and T5 diets versus the control. In addition, the dietary Cu-NPs and VC supplementations significantly enhanced resistance against pathogens and led to the control of infection in rainbow trout. In conclusion, Cu-NPs and VC administered as feed additives at 2/250-500 mg/kg elevated the growth performance, antioxidant capacity, and health of rainbow trout.

A Degradable, Broad-Spectrum and Resistance-Resistant Antimicrobial Oligoguanidine as Disinfecting and Therapeutic Agent in Aquaculture

The threat of antibiotic resistance to community healthcare and global economy has raised extensive concern, and the over-use of antibiotics in animal husbandry plays a significant role in the occurrence...

Molecular characterization of superoxide dismutase and catalase genes, and the induction of antioxidant genes under the zinc oxide nanoparticle-induced oxidative stress in air-breathing magur catfish (Clarias magur)

The deduced amino acid sequences from the complete cDNA coding sequences of three antioxidant enzyme genes (sod1, sod2, and cat) demonstrated that phylogenetically the magur catfish (Clarias magur) is very much close to other bony fishes with complete conservation of active site residues among piscine, amphibian, and mammalian species. The three-dimensional structures of three antioxidant enzyme proteins are very much similar to mammalian counterparts, thereby suggesting the functional similarities of these enzymes. Exposure to ZnO NPs resulted in an oxidative stress as evidenced by an initial sharp rise of intracellular concentrations of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) but decreased gradually at later stages. The level of glutathione (GSH) also increased gradually in all the tissues examined after an initial decrease. Biochemical and gene expression analyses indicated that the magur catfish has the ability to defend the ZnO NP-induced oxidative stress by inducing the SOD/CAT enzyme system and also the GSH-related enzymes that are mediated through the activation of various antioxidant-related genes both at the transcriptional and translational levels in various tissues. Furthermore, it appeared that the stimulation of NO, as a consequence of induction nos2 gene, under NP-induced oxidative stress serves as a modulator to induce the SOD/CAT system in various tissues of magur catfish as an antioxidant strategy. Thus, it can be contemplated that the magur catfish possesses a very efficient antioxidant defensive mechanisms to defend against the oxidative stress and also from related cellular damages during exposure to ZnO NPs into their natural environment.

The Physical Modeling Analysis of Fate and Transport of Silver Nanoparticles Dispersed by Water Flow

The release of silver nanoparticles (AgNPs) from consumer products into an environment has become a central issue for many countries. Despite that the fate and behaviors of AgNPs incorporated into a wastewater have been investigated by building a model of wastewater treatment process, the transport and retention behaviors of AgNPs influenced by the water flow in a river must be understood. The physical model of simulated river to mimic a natural flow of river was proposed to investigate the behaviors of AgNP transport in the river. The results showed that the large amount of AgNPs deposited on the riverbed as Ag sediment with only 1.26% of AgNPs remained in the water flow. The elemental content of Ag freely dispersed across the riverbed increases from the upstream to downstream area of the simulated river. Verification of the spatial distribution of Ag dispersed along the water flow may contribute to a better understanding of the fate and transport of AgNPs in the aquatic environment.

Ameliorative role of ascorbic acid on the oxidative stress and genotoxicity induced by acetamiprid in Nile tilapia (Oreochromis niloticus)

On juveniles of Oreochromis niloticus, the protective potential of ascorbic acid (Asc) against oxidative stress and genotoxicity induced by acetamiprid (Aceta) sub-lethal concentrations was investigated in this study. Fishes were divided into six groups and exposed to either Asc (50 ppm), 10 and 20 ppm Aceta, 10 ppm (Aceta)+Asc, 20 ppm (Aceta)+Asc, or the unexposed control group. Superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) activities and their transcripts were assessed. DNA damage in erythrocytes, hepatocytes, and gill cells, in addition to the mitotic index (MI), and the existence of erythrocytic nuclear abnormalities (ENAs) were performed. The results showed that concentrations of Aceta (10 and 20 ppm) induced oxidative stress by altering the antioxidant enzyme activities and transcripts. There were genotoxic effects of Aceta exposure showed by the significant (P < 0.05) increase in DNA-damaged cells and ENA, meanwhile a decrease in MI. Co-exposure with Asc showed significant alleviations of oxidative status and genotoxicity. Thus, results suggest that Asc-combined exposure could be the effective treatment against Aceta-induced oxidative stress accompanied with genotoxicity in O. niloticus.

Toxicity, inflammatory and antioxidant genes expression, and physiological changes of green synthesis silver nanoparticles on Nile tilapia (Oreochromis niloticus) fingerlings

The rapid increase of incorporating silver nanoparticles (Ag-NPs) in different anthropogenic and industrial activities increased the discharge of these particles in the aquatic ecosystem. The environmental impact of Ag-NPs, especially the green synthesized is still not completely understood on fish. Therefore, this study aimed to investigate the effects of exposure to graded series of starch-mediated Ag-NPs at levels of 0, 3.31, 6.63, 13.25, and 26.50 mg L^-1 representing 0, 6.25, 12.5, 25, and 50% of LC₅₀ on Nile tilapia (O. niloticus), respectively. Fish with initial weight 37.63 ± 0.41 g were maintained in 70 L glass aquaria and exposed to starch-mediated Ag-NPs (average particle size 40 nm) for 28 days. The results revealed that starch-mediated Ag-NPs induced severe changes in the mRNA levels of toxicity (CYP1A and Hsp70) and inflammatory (TNF-α and TGF-β) genes. The expression of antioxidant genes (SOD and CAT) was significantly suppressed, and the activities of their enzymes were inhibited significantly upon exposure. Simultaneously, the malondialdehyde level increased significantly with increasing the exposure levels of starch-mediated Ag-NPs. The red blood cells, hemoglobin, hematocrit and white blood cell values were decreased significantly with doses over 3.31 mg L^-1 of Ag-NPs. In addition, the total protein and globulin decreased significantly with increasing Ag-NPs in a dose-dependent manner. The liver function enzymes and kidney function indicators revealed severe toxicity with Ag-NPs exposure. In conclusion, the effect of starch-mediated Ag-NPs in doses over 3.31 mg L^-1 induced obvious toxicity in the molecular and proteomic levels in Nile tilapia fingerlings.

Dietary Synbiotics Can Help Relieve the Impacts of Deltamethrin Toxicity of Nile Tilapia Reared at Low Temperatures

The optimal water temperature for the normal growth of Nile tilapia is between 26 and 28 °C, and the toxicity of pesticides is strongly related to water temperature. An alternate approach to augmenting the resistance of fish to ambient water toxicity and low water temperature via synbiotic feeding was proposed. In this study, fish were allocated into four groups with 10 fish in each replicate, where they were fed a basal diet or synbiotics (550 mg/kg) and kept at a suboptimal water temperature (21 ± 2 °C). The prepared diets were fed to Nile tilapia for 30 days with or without deltamethrin (DMT) ambient exposure (15 μg/L). The groups were named control (basal diet without DMT toxicity), DMT (basal diet with DMT toxicity), synbiotic (synbiotics without DMT toxicity), and DMT + synbiotic (synbiotics with DMT toxicity). The results displayed upregulated transcription of catalase, glutathione peroxidase, and interferon (IFN-γ) genes caused by DMT exposure and synbiotic feeding when compared with the controls. Moreover, HSP70 and CASP3 genes displayed increased transcription caused by DMT exposure without synbiotic feeding. However, fish fed with synbiotics showed downregulated HSP70 and CASP3 gene expressions. The transcription of IL-1β and IL-8 genes were also decreased by DMT exposure, while fish fed synbiotics showed upregulated levels. DMT exposure resulted in irregular histopathological features in gills, intestine, spleen, and liver tissues, while fish fed synbiotics showed regular, normal, and protected histopathological images. Our results indicated that dietary synbiotics ameliorated histopathological damages in DMT-exposed tilapia through alleviation of oxidative stress and inflammation as well as enhancing the immunity.

Dietary exposure to methyl mercury chloride induces alterations in hematology, biochemical parameters, and mRNA expression of antioxidant enzymes and metallothionein in Nile tilapia

Methyl mercury chloride "MMC" (CH₃ClHg) is an ubiquitous environmental toxicant that causes a variety of adverse effects. In the present study, we investigated the effects of sub-chronic toxicity of MMC on Nile tilapia (Oreochromis niloticus) through the evaluation of growth performance and hematological, biochemical, and oxidative stress biomarkers. From 150 healthy fish, five equally sized treatment groups were created: a control (CT) group fed with a basal diet and four MMC treatment groups exposed to 0.5, 1, 1.5, and 2 mg of MMC per kg of basal diet for 60 days. MMC exposure significantly reduced the growth performance and survival of O. niloticus and decreased red blood cell count and hemoglobin concentration. Treated fish exhibited normocytic normochromic anemia in addition to leucopenia, lymphopenia, granulocytopenia, and monocytopenia. Moreover, MMC exposure significantly affected liver function, including a reduction in the total protein levels while increasing cholesterol and triglyceride levels. It also markedly increased the production of stress biomarkers such as glucose and cortisol levels. Furthermore, MMC significantly elevated the levels of hepatic enzymes, induced tissue damage, and caused inflammation, as indicated by the upregulation of mRNA expression of hepatic metallothionein. Finally, MMC exposure induced oxidative stress by altering the antioxidant status of the liver and downregulating the mRNA expression of superoxide dismutase, glutathione peroxidase, and glutathione S-reductase. In conclusion, MMC toxicity induced hematological and biochemical alterations, leading to an enhanced state of oxidative stress in O. niloticus.

Dietary supplementation with melatonin: influence on growth performance, oxidative stress status, and amelioration of silver nanoparticles-induced toxicity in Nile tilapia (Oreochromis niloticus)

Excessive use of silver nanoparticles (AgNPs) due to antibacterial properties can raise concerns about their release into environment and potential toxicity in aquatic organisms. Melatonin has several physiological functions especially antioxidant potential against oxidative stress. The current study was conducted to investigate the potential effects of two doses of dietary melatonin on growth performance, plasma biochemistry, and liver enzyme activity in Nile tilapia (Oreochromis niloticus) juveniles. We also investigated the potential ameliorative effect of melatonin in AgNPs-induced biochemical alterations in tilapia fish. The results showed that melatonin-supplemented diets had no significant effect on growth performance of fish (P>0.05). The liver GPx activity increased in fish fed melatonin-supplemented diets (P<0.05), but the SOD activity showed no significant difference in comparison with the control (P>0.05). The administration of melatonin-supplemented diets reduced the activity of liver MDA compared to the control (P<0.05). Feeding fish with high melatonin-supplemented diet (200 mg kg^-1 of diet) decreased the plasma glucose, total protein, and AST levels (P<0.05). The liver GPx and SOD activities were higher in high melatonin-treated fish exposed to AgNPs than the control group (P<0.05). Dietary melatonin decreased the liver MDA activity in AgNPs-exposed fish. The plasma glucose, AST, and ALT levels in melatonin-treated fish exposed to AgNPs decreased compared to the untreated exposed fish (P<0.05). Melatonin-treated fish exposed to 0.05 and 0.5 mg L^-1 of AgNPs had lower plasma LDH level than the control group (P<0.05). The results showed that consumption of melatonin-supplemented diets could modulate some of the biochemical indices of plasma and liver in Nile tilapia. The findings also indicated the ameliorative effect of dietary melatonin on AgNPs-induced toxicity in Nile tilapia.

Antioxidant properties of dietary supplements of free and nanoencapsulated silymarin and their ameliorative effects on silver nanoparticles induced oxidative stress in Nile tilapia (Oreochromis niloticus)

Silver nanoparticles (AgNPs) are increasingly used in a wide range of products and as a consequence, the environmental concentration will inevitably increase in the near future. Many aquatic organisms have been shown to be sensitive to the toxic effects of silver, including oxidative stress mechanisms. In this study, we assessed the ability of silymarin (Silybum marianum) to counter the oxidative effects of AgNPs in Nile tilapia (Oreochromis niloticus). Fish were fed on the diets supplemented with 50 or 200 mg kg^-1 of free or nanoencapsulated silymarin for 50 days. Subsequently, they were exposed via the water to three concentrations (0.05, 0.1, and 0.5 mg L^-1) of AgNPs for 24 h, and the effects of this exposure assessed on blood plasma and liver oxidative status. Growth performance and most body indices measured were not affected by any of the experimental diets. There were no effects of free silymarin (FS) or nanoencapsulated silymarin (NS) on levels of plasma aspartate aminotransferase (AST), alanine transaminase (ALT), or on the total protein (TP). In contrast, malondialdehyde (MDA) content, glutathione peroxidase (GPx) activity, and plasma glucose (GLU) were all affected by the high dietary FS and NS treatments compared with controls. Prior to the AgNPs exposure, the levels of SOD and GPx activity were higher and MDA levels lower in the silymarin treatment groups compared to controls. Exposure to AgNPs resulted in a reduction in the levels of GPx and SOD activity and an increase in the level of MDA that was dependent on the exposure concentrations of AgNPs. Based on GPx, MDA, and GLU indices, both forms of silymarin decreased the toxicity of AgNPs, but NS supplementation was the most effective. Thus, we show dietary silymarin supplementation can reduce AgNP toxicity and nanoencapsulation increases its efficacy as an antioxidant.

Antagonistic effect of different selenium type on green synthesized silver nanoparticle toxicity on Oreochromis niloticus: oxidative stress biomarkers

The current investigation pointed to report the negative impacts of silver nanoparticles [Ag]^NPs that synthesized by leaf extract of Moringa oleifera on oxidative stress biomarkers of Oreochromis niloticus, as well as the role of different Selenium type to antagonistic that toxicity. Fish were exposed to [Ag]^NPs (1.95 and 3.9 ppm) as sublethal concentrations alongside 0.1 ppm of Se bulk and 0.1 ppm biosynthesized [Se]^NPs selenium nanoparticles antagonistic effect for 2 and 4 weeks. Lipid peroxidation (LPO), DNA fragmentation, total antioxidant capacity (TAOC), catalase (CAT), and superoxide dismutase (SOD) were evaluated as oxidative stress biomarkers,. A significant increase (p < 0.05) in LPO and DNA fragmentation and a significant decrease (p < 0.05) in TAOC, CAT, and SOD were found in [Ag]^NPs exposed groups when compared with the control one. Biosynthesized [Se]^NPs and Se bulk showed a positive role in [Ag]^NPs detoxification. Our investigation suggested that [Ag]^NPs showed a toxic effect on oxidative stress biomarkers. However, Se-NP addition gives a good recovery of oxidative biomarkers more than Se bulk in detoxification of [Ag]^NPs.

Does the adsorbent capacity of orange and banana peels toward silver nanoparticles improve the biochemical status of Oreochromis niloticus?

Silver nanoparticles (Ag NPs) have wide medical and industrial applications; therefore, their release into aquatic environments is a problematic issue. The present study aims to evaluate the removal efficiency of Ag NPs from water using orange peel (OP) and banana peel (BP) to moderate their toxicity on Oreochromis niloticus. Fish were divided into 4 groups: control group (dechlorinated tap water), Ag NPs (4 mg/L) exposed group, Ag NPs (4 mg/L) + OP (40 mg/L) group, and Ag NPs (4 mg/L) + BP (40 mg/L) group for 24 h, 48 h, and 96 h. The adsorptive ability of both peels was confirmed by scanning electron microscope and energy-dispersive X-ray spectroscopy after the exposure processes. The biochemical results revealed a gradual elevation in plasma glucose, total proteins, globulin, liver enzymes (AST, ALT, and ALP), creatinine, and uric acid after Ag NPs exposure, while albumin and total lipid concentrations were significantly decreased. The recorded antioxidant biomarkers in gills, and liver tissues after Ag NPs exposure showed severe oxidative damages (maximally after 96 h) as indicated by marked elevations in thiobarbituric acid reactive substances, glutathione peroxidase, catalase, and superoxide dismutase values, and decreased glutathione reduced content. All studied parameters restored more or less to that of control groups after OP and BP water treatment. The adsorbent abilities of both peels could reduce Ag NPs bioavailability and moderate their toxicological impacts.

Effects of different LED light spectra on rainbow trout (Oncorhynchus mykiss): in vivo evaluation of the antioxidant status

Rainbow trout (Oncorhynchus mykiss) farming is one of the major aquacultures in Turkey. Some conditions in fish farming can induce oxidative stress leading to the deterioration in properties such as appearance/color, texture, and flavor in fish meat. This situation may cause the consumer not to prefer edible fish. Although there are some studies on the impacts of light intensity on fish welfare, the changes in the antioxidant enzyme activities have not been elucidated. In the current study, it was intended to examine in rainbow trout how cultivating under different wavelengths affects the antioxidant enzymes and acetylcholine esterase (AChE) activity, because its activity is associated with oxidative stress, and also the determination of which light is suitable for fish welfare was aimed. Rainbow trout larvae were grown under four lights with different wavelengths: natural sunlight and incandescent long-wave (red light), medium-wave (green light), and short-wave (blue light) LED light. The experiment lasted for 64 days. Biochemical assays were carried on in the brain, gill, and liver of rainbow trout. Antioxidant enzymes and AChE activity, which play an important role in the central nervous system, were assayed. In gill tissues, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glucose 6 phosphate dehydrogenase (G6PD), glutathione reductase (GR), glutathione S-transferase (GST), and AChE activities increased under all three light wavelengths. In the liver, while activities of antioxidant enzymes and AChE decreased in red light, all of them increased in blue and green light. In the brain, GPx, GST, G6PD, and SOD activities were reduced but AChE activity did not alter under all three light sources. In conclusion, light sources with different spectral structures caused important changes in the activities of antioxidant enzymes in rainbow trout. On this basis, it may be thought that this may be a response to the changing redox status of a cell. Based on our results, blue light sources may be suggested for fish welfare in rainbow trout culture, and providing fish welfare by changing light sources can be easy and cheap in fish farming.

Combined effects of exposure to engineered silver nanoparticles and the water-soluble fraction of crude oil in the marine copepod Calanus finmarchicus

While it is likely that ENPs may occur together with other contaminants in nature, the combined effects of exposure to both ENPs and environmental contaminants are not studied sufficiently. In this study, we investigated the acute and sublethal toxicity of PVP coated silver nanoparticles (AgNP) and ionic silver (Ag⁺; administered as AgNO₃) to the marine copepod Calanus finmarchicus. We further studied effects of single exposures to AgNPs (nominal concentrations: low 15 μg L^-1 NPL, high 150 μg L^-1 NPH) or Ag⁺ (60 μg L^-1), and effects of co-exposure to AgNPs, Ag⁺ and the water-soluble fraction (WSF; 100 μg L^-1) of a crude oil (AgNP + WSF; Ag⁺+WSF). The gene expression and the activity of antioxidant defense enzymes SOD, CAT and GST, as well as the gene expression of HSP90 and CYP330A1 were determined as sublethal endpoints. Results show that Ag⁺ was more acutely toxic compared to AgNPs, with 96 h LC₅₀ concentrations of 403 μg L^-1 for AgNPs, and 147 μg L^-1 for Ag⁺. Organismal uptake of Ag following exposure was similar for AgNP and Ag⁺, and was not significantly different when co-exposed to WSF. Exposure to AgNPs alone caused increases in gene expressions of GST and SOD, whereas WSF exposure caused an induction in SOD. Responses in enzyme activities were generally low, with significant effects observed only on SOD activity in NPL and WSF exposures and on GST activity in NPL and NPH exposures. Combined AgNP and WSF exposures caused slightly altered responses in expression of SOD, GST and CYP330A1 genes compared to the single exposures of either AgNPs or WSF. However, there was no clear pattern of cumulative effects caused by co-exposures of AgNPs and WSF. The present study indicates that the exposure to AgNPs, Ag⁺, and to a lesser degree WSF cause an oxidative stress response in C. finmarchicus, which was slightly, but mostly not significantly altered in combined exposures. This indicated that the combined effects between Ag and WSF are relatively limited, at least with regard to oxidative stress.

Biochemical, Toxicological, and Histopathological outcome in rat brain following treatment with NiO and NiO nanoparticles

Nickel oxide nanoparticle (NiO NPs) has been widely used in various fields such as catalysts, radiotherapy, and nanomedicine. The aim of this study was to compare the effects of nickel oxide (NiO) and NiO NPs on oxidative stress biomarkers and histopathological changes in brain tissue of rats. In this study, 49 male rats were randomly divided into one control group and 6 experimental groups (n = 7). The control group received normal saline and the treatment groups received NiO and NiO NPs at doses of 10, 25, and 50 mg/kg intraperitoneally for 8 days. After 8 days, animal was sacrificed, brain excised, homogenized, centrifuged, and then supernatant was collected for antioxidant assays. The results showed that activity of GST in NiO NPs groups with doses of 10, 25, and 50 mg/kg (79.42 ± 4.24, p = 0.035; 78.77 ± 8.49, p = 0.041; 81.38 ± 12.39, p = 0.042 to 47.26 ± 7.17) and catalase in NiO NPs groups with concentrations of 25 and 50 mg/kg (69.95 ± 8.65 to 39.75 ± 5.11, p = 0.02) and (68.80 ± 4.18 to 39.75 ± 5.11 p = 0.027) were significantly increased compared with the control, respectively. Total antioxidant capacity in NiONPs group with doses of 50 mg/kg was significantly decreased (345.00 ± 23.62, p = 0.015 to 496.66 ± 25.77) compared with control. The GSH level in all doses NiO and NiONPs was significantly decreased compared with the control (p = 0.002). MDA level in NiONPs and NiO groups with doses of 50 mg/kg was significantly increased (13.03 ± 1.29, p = < 0.01; 15.61 ± 1.08, p = < 0.001 to 7.32 ± 0.51) compared with the control, respectively. Our results revealed a range of histopathological changes, including necrosis, hyperemia, gliosis, and spongy changes in brain tissue. Thus, increasing level of MDA, GST, and CAT enzymes and decreasing GSH and TAC and also histopathological changes confirmed NiONPs and NiO toxicity.

The impact of menthol essential oil against inflammation, immunosuppression, and histopathological alterations induced by chlorpyrifos in Nile tilapia

Chlorpyrifos (CPF) is one of the predominant water pollutants associated with inflammation and immunodepression in aquatic animals. In this study, menthol oil (MNT) impacted the immunity, antioxidative, and anti-inflammatory responses against CPF toxicity in Nile tilapia. Fish fed two diets with or without MNT and placed in four groups (control, CPF, MNT, and CPF/MNT). After 30 days, fish fed MNT displayed higher growth performance and lower FCR than CPF-intoxicated fish without feeding MNT (P < 0.05). The survival rate of fish was reduced in the CPF group without MNT feeding (P < 0.05). Blood Hb, PCV, RBCs, and WBCs were decreased in fish by CPF toxicity, while the highest Hb, PCV, RBCs, and WBCs were observed in fish fed MNT followed by those fed the control without CPF toxicity (P < 0.05). Fish fed MNT had the highest total protein, albumin, and globulin, as well as the lowest urea, bilirubin, and creatinine after 15 and 30 days. However, fish under CPF toxicity had the most inferior total protein, albumin, and globulin, as well as the highest urea, bilirubin, and creatinine among the groups (P < 0.05). The enzyme activities of ALP and ALT displayed low levels by MNT with or without CPF exposure than fish fed without MNT with or without CPF exposure after 15 and 30 days (P < 0.05). The lysozyme and phagocytic activities displayed reduced levels by CPF without MNT feeding after 15 and 30 days, while increased activities were noticed by MNT feeding without CPF toxicity followed by fish fed MNT with CPF toxicity (P < 0.05). The transcription of CAT and GPX genes displayed upregulated levels in tilapia fed MNT and exposed to CPF (P < 0.05). Also, CPF toxicity increased the transcription of the IFN-γ gene but decreased the IL-8 and IL-1β genes. The transcription of HSP70 displayed lower levels (P < 0.05) by CPF without supplementing MNT than fish fed MNT and exposed to CPF. Histopathological analysis revealed that inflammation existed in the liver, gills, and intestine of tilapia due to CPF toxicity while MNT protected tissues from inflammation. To conclude, MNT activated the immunity, antioxidative, and anti-inflammatory responses of Nile tilapia under CPF toxicity.

Melatonin protects sperm cells of Capoeta trutta from toxicity of titanium dioxide nanoparticles

In this study, it was aimed to determine the protective effects of melatonin (0.01, 0.1, and 1 mM) against 10 mg/L titanium dioxide nanoparticles (TiO2-NPs) on kinematic and oxidative indices in the sperm cells of Capoeta trutta. Therefore, TiO2 nanoparticles were synthesized primarily within the scope of the study. The synthesized nanoparticles were characterized by structurally different techniques. Then, melatonin and TiO2 were applied to Capoeta trutta sperm cells by in vitro. According to our data, all doses of melatonin showed protective effects on all velocities of sperm cells such as the straight line velocity (VSL), the curvilinear velocity (VCL), and the angular path velocity (VAP) against TiO2-NPs, while 0.1 and 1 mM doses of melatonin improved the VSL value. Although TiO2-NPs increased total glutathione (tGSH), malondialdehyde (MDA) lipid peroxidation, and superoxide dismutase (SOD) compared to the control group, there were positive treatment effects for all doses of melatonin on antioxidant capacity of sperm cells. At the end of this research, it is suggested that over 0.1 mM dose of melatonin improves the velocity of sperm cells and it plays a protective role against the toxic effects of TiO2-NPs.

Toxicological impact of green synthesized silver nanoparticles and protective role of different selenium type on Oreochromis niloticus: hematological and biochemical response

BACKGROUND

The present work aimed to detect the toxicological effects of green synthesized silver nanoparticles (Ag-NPs) by using Moringa Oleifera leaves extract on hematological and biochemical parameters of Oreochromis niloticus.

METHODS

Adult fish were exposed to two sublethal concentrations (1.95 and 3.9 ppm) of Ag-NPs against sodium selenite (0.1 ppm) and biosynthesized selenium nanoparticles (Se-NPs); 0.1 ppm; protection role for 2 and 4 weeks. Hematological parameters; erythrocyte count (RBCs), hemoglobin content (Hb), haematocrit value (Hct), mean corpuscular volume (MCV), Mean Corpuscular Hemoglobin Concentration (MCHC), leucocytes (WBCs), with differential count Micronucleus (MN) and alerted cells and biochemical parameters; aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) enzyme activities, serum protein (total protein, albumin and globulin) concentration, urea, creatinine, glucose, cholesterol (Cho) and triglyceride (Tg) were detected.

RESULTS

The present investigation showed that Ag-NPs in different doses led to a significant reduction (p < 0.05) in RBCs, Hb, Hct, MCV, WBCs, LYM and serum proteins concentration. However, MCHC, MN, alerted cells, NEUT, AST, ALT, ALP enzyme activities, urea, creatinine, glucose, Cho and Tg showed a significant increases (p < 0.05) when compared with control group. Sodium selenite (Se) and biosynthesized selenium nanoparticles (Se-NPs) play an optimistic role in detoxification of Ag-NPs toxicity.

CONCLUSION

The results suggest the negative impact of Ag-NPs on hematology and biochemical parameters of fish. Moreover, Se-NPs showed a full improvement of hematological and biochemical parameters more than that of sodium selenite in elimination of Ag-NPs toxicity.

Impact of wastewater-borne nanoparticles of silver and titanium dioxide on the swimming behaviour and biochemical markers of Daphnia magna: An integrated approach

Due to their widespread use, silver (Ag) and titanium dioxide (TiO₂) nanoparticles (NPs) are commonly discharged into aquatic environments via wastewater treatment plants. The study was aimed to assess the effects of wastewater-borne AgNPs (NM-300 K; 15.5 ± 2.4 nm; 25-125 μg L^-1) and TiO₂NPs (NM-105; 23.1 ± 6.2 nm; 12.5-100 μg L^-1), from a laboratory-scale wastewater treatment plant, on Daphnia magna, at individual and subcellular level. For effect comparison, animals were also exposed to ASTM-dispersed NPs at the same nominal concentrations. The behaviour of D. magna was evaluated through monitoring of swimming height and allocation time for preferred zones after 0 h and 96 h of exposure. Biochemical markers of neurotransmission, anaerobic metabolism, biotransformation, and oxidative stress were subsequently determined. No 96-h EC₅₀ (immobilization ≤ 4 %) could be obtained with wastewater-borne NPs and ASTM-dispersed TiO₂NPs, whereas the ASTM-dispersed AgNPs resulted in an immobilization 96-h EC₅₀ of 113.8 μg L^-1. However, both wastewater-borne and ASTM-dispersed TiO₂NPs, at 12.5 μg L^-1, caused immediate (0 h) alterations on the swimming height. Allocation time analyses showed that animals exposed to ASTM-dispersed AgNPs spent more time on the surface and bottom at 0 h, and in the middle and bottom at 96 h. This pattern was not observed with ASTM-dispersed TiO₂NPs nor with wastewater-borne AgNPs and wastewater-borne TiO₂NPs. At the biochemical level, the more pronounced effects were observed with wastewater-borne AgNPs (e.g. induction of lactate dehydrogenase and glutathione S-transferase activities, and inhibition of catalase activity). This integrative approach showed that: (i) the behavioural and biochemical response-patterns were distinct in D. magna exposed to environmentally relevant concentrations of wastewater-borne and ASTM-dispersed NPs; (ii) the most pronounced effects on allocation time were induced by ASTM-dispersed AgNPs; and (iii) at the subcellular level, wastewater-borne AgNPs were more toxic than wastewater-borne TiO₂NPs. This study highlights the need for the assessment of the effects of wastewater-borne NPs under realistic exposure scenarios, since processes in wastewater treatment plants may influence their toxicity.

The influence of dietary β-glucan on immune, transcriptomic, inflammatory and histopathology disorders caused by deltamethrin toxicity in Nile tilapia (Oreochromis niloticus)

The protective role of β-glucan (BG) on liver function, histopathology, immune and antioxidant related gene expressions in Nile tilapia exposed to subacute deltamethrin (DLM) was investigated for 30 days. Fish (28.18 ± 1.34 g) of the 1st and 2nd groups fed the control diet, while the 3rd and 4th groups fed BG at 0.5 g/kg and the 2nd and 4th groups were exposed to DLM (15 μg/L) in rearing water. DLM-treated fish displayed a considerable increase in blood biochemical parameters (creatinine, urea and bilirubin) as well as hepatic enzymes (ALP, AST and ALT) (P < 0.05). Blood total protein, globulin, albumin, WBCs, RBCs, Hb, phagocytic index, phagocytic and lysozyme activities were significantly decreased in fish subjected to DLM (P < 0.05). Fish fed BG showed significantly the lowest cortisol and glucose levels, while fish exposed to DLM without feeding BG showed the highest cortisol and glucose levels (P < 0.05) after 15 and 30 days. Additionally, DLM toxicity caused downregulation in antioxidant (CAT and GPx) and immune (IL-1β and IL-8) related gene expressions, while and IFN-γ, HSP70 and CASP3 were upregulated. The histopathological examination of Nile tilapia exposed to DLM revealed damage in gills, intestine, spleen and liver which confirmed the toxic effects. Conversely, BG presented protective effects and restored the above-mentioned parameters when fish exposed to DLM and fed BG. Thus, BG supplementation exhibited defensive effects against DLM toxicity in Nile tilapia through improving blood biochemical responses, immune, and antioxidant related gene expressions as well as histopathological effects.

Ameliorative effects of Lactobacillus plantarum L-137 on Nile tilapia (Oreochromis niloticus) exposed to deltamethrin toxicity in rearing water

Deltamethrin (DLM) is a synthetic pyrethroid used for agricultural purposes to control insects and has been found to pollute the aquatic environment and leads to serious health problems. Lactobacillus plantaruml-137 (L-137) has gained more popularity as functional supplement for its immunomodulatory effects and antioxidant potential. This study was designed to examine the potential of l-137 on liver function, histopathology, immune and antioxidant related gene expressions in Nile tilapia exposed to subacute DLM for 30 days. Fish (mean weight of 28.18 ± 1.34 g) was distributed into four groups (triplicates): the first and second groups fed the control diet, while the third and fourth groups fed l-137 at 50 mg/kg and the second and fourth groups were exposed to DLM (15 μg/L) in rearing water (control, DLM, l-137 and DLM + L-137, respectively). DLM-treated fish groups showed a significant increase in blood biochemical parameters (creatinine, urea and bilirubin) as well as hepatic enzymes (ALP, AST and ALT) (P < 0.05). Blood total protein, globulin, albumin, WBCs, RBCs, Hb, phagocytic index, phagocytic and lysozyme activities were significantly decreased in fish exposed to DLM (P < 0.05). Additionally, DLM toxicity downregulated the transcription of immune genes (IL-1β and IL-8), while upregulated the stress related genes (HSP70 and CASP3). The histopathological images of Nile tilapia exposed to DLM revealed damage in gills, intestine, spleen and liver which confirmed the toxic effects. Conversely, l-137 presented protective effects and restored the aforementioned parameters when fish exposed to DLM and fed l-137. Further, l-137 restored the antioxidative capacity (CAT and GPx). Thus, l-137 supplementation exhibited defensive effects against DLM toxicity in Nile tilapia through improving blood biochemical responses, immune, and antioxidant related gene expressions as well as histopathological effects.

Neurotoxicity of green- synthesized magnetic iron oxide nanoparticles in different brain areas of wistar rats

AIMS

The aim of the present study was to evaluate the toxicity of magnetic iron oxide nanoparticles (MIONs) which were synthesized using carob leaf extract on various brain areas of Wistar rats.

MAIN METHODS

Carob leaf synthesized-MIONs were characterized using different techniques: Dynamic Light Scattering (DLS), Transmission Electron Microscope (TEM), UV-vis spectrophotometer, Fourier Transform infrared (FTIR), X-Ray Diffraction (XRD) and Atomic Force Microscope (AFM). The toxicity of MIONs in vivo was evaluated by: monitoring rat's body weight, measuring iron content in different brain areas, evaluating some oxidative stress parameters, estimating acetylcholinesterase (AChE) in addition to histopathological investigations.

KEY FINDINGS

The present study demonstrated no body weight changes of MIONs- treated rats. According to the conditions of the present study, the hippocampus and striatum were the most affected areas and demonstrated neuronal degeneration due to MIONs exposure. MIONs treatment of Wistar rats, also affected the iron homeostasis in both striatum and midbrain by decreasing iron content in these areas. The least affected areas were thalamus and cerebellum. The histopathological examination of brain areas demonstrated moderate neuronal degeneration in hippocampus and striatum, mild neuronal degeneration in cortex and slight degeneration in hypothalamus and pons-medulla areas were detected.

SIGNIFICANCE

The results suggested that MIONs have a toxic impact on different brain areas and the effect varies according to the brain area.

Silver nanoparticles are lethal to the ciliate model Tetrahymena and safe to the pike silverside Chirostoma estor

Ciliate ectoparasites are one of the most important groups of pathogens in fish culture, and the traditional treatments are sometimes harmful to the fish and the environment. Thus, the search for novel compounds that are effective at low concentrations and safe for fish are necessary to optimise treatments in aquaculture. The antiprotozoal capacity of silver nanoparticles (AgNPs) against the ciliate Tetrahymena has been documented; however, their toxicity may vary with the synthesis methodology and nanoparticle size. The objectives of this study were a) to evaluate the acute toxicity in vitro of two AgNPs (Argovit™ and UTSA) on Tetrahymena sp., a biological model for ciliated ectoparasites of fish and b) to test the safety of lethal and higher doses of UTSA AgNPs for ciliates on the fish C. estor. Light microscopy and scanning electron microscopy (SEM) were used to determine whether AgNPs affected the structure of the cell surface of Tetrahymena. The mortality, histopathological alterations and metagenomics of the fish were used to determine the major effects of UTSA AgNPs. In Tetrahymena, the median lethal concentration (LC₅₀) for Argovit™ was 2501 ± 1717 ng/L at 15 min and 796 ± 510 ng/L at 60 min, while the LC₅₀ for UTSA AgNPs was 4 ± 2 and 1 ± 0.6 ng/L at 15 min and 60 min, respectively. A concentration of 3300 ng/L Argovit™ and 10.6 ng/L UTSA AgNPs for 15 and 60 min, respectively, was 100% effective against Tetrahymena. After 60 min of exposure to 0.25 and 0.50 ng/L UTSA AgNPs, the number of cilia significantly reduced, there were small holes on the cell surface, and the cellular membrane was ruptured. In fish exposed to lethal (10.6 ng/L) and higher (31.8 and 95.4 ng/L) doses of UTSA, the AgNPs did not affect fish survival after 96 h, and there were no signs of histopathological damage or gut microbial changes. This study is the first report on microscopic and ultrastructural changes in Tetrahymena after exposure to significantly low concentrations of UTSA AgNPs with antiprotozoal efficacy without evidence of harmful effects on fish. These results provide the basis for further studies of both pet aquarium and commercial fish that may validate these findings at a larger experimental scale, taking into account AgNPs bioaccumulation, safety for human consumption and environmental impact.

Changes in Brain Acetylcholinesterase and Oxidative Stress Biomarkers in African Catfish Exposed to Carbendazim

Carbendazim (CBZ) is a widely used, systemic, broad-spectrum benzimidazole fungicide. It is used worldwide against fungal diseases on a wide range of agricultural products and in domestic gardens. The activities of brain oxidative stress biomarkers and acetylcholinesterase (AChE) in juvenile African Catfish Clarias gariepinus exposed to CBZ were investigated. Juveniles were exposed to sublethal concentrations of 0.22, 0.43, and 0.64 mg/L CBZ, which corresponded to 5, 10, and 15% of the 96-h LC50 (the concentration that was lethal to 50% of the test organisms over the first 96 h) of CBZ fungicide for 21 d. Individuals were allowed an extra 7-d recovery period. The brain tissues were sampled and analyzed on days 1, 7, 14, 21, and 28 (including the 7-d recovery period). The results indicated significant concentration-dependent inhibition of the brain AChE activities in all exposed groups. The lipid peroxidation was significantly elevated while the antioxidant enzymes and protein values were significantly inhibited by CBZ exposure. However, the values of catalase on days 7, 14, and 21 were significantly higher than day 1 values. Overall, CBZ altered brain oxidative stress parameters and led to the inhibition of AChE. This fungicide should be used with utmost caution to protect and safeguard fish, ensuring that fish production and survival in the environment remain unaffected.

Efficacy of nanoencapsulated pelargonidin in ameliorating pesticide toxicity in fish and L6 cells: Modulation of oxidative stress and signalling cascade

Removal of bio-accumulated pesticides in edible fish is a global problem. In this study, we tested protective capability of a phytochemical pelargonidin-loaded non-toxic, biodegradable poly-lactide-co-glycolide nano-particles (NPG) against toxicity induced by a pesticide cypermethrin (CM) in a fish model (Oreochromis mossambica) in vivo and also in L6 muscle cell line, in vitro. First we assessed potential sustainable release of nanoparticles following oral administration of NPG to fish, their ability to cross sub-cellular membranes in several tissues and efficacy to cross blood-brain-barrier. Next, protective ability of NPG, if any, against CM in fish was evaluated deploying parameters like % cell viability, DNA damage in muscle cells and modulation of anti-oxidative-enzymes like superoxide dismutase, catalase and lipid peroxidase. Modulation of reactive oxygen species generation, nuclear condensation and alteration in stress related protein signalling cascade were assessed in L6 cells. Results revealed that NPG had nano-size range (~10-12 nm) and negative zeta potential (-17 mV). Bioavailability and distribution of NPG could be followed by spectrophotometric absorbance of pelargonidin at 293 nm from 6 h onward till 24 h in all important tissues including the brain. Thus, 0.5 mg/g b.w. NPG could demonstrate protective ability in CM-intoxicated fish muscle cells in respect of % cell viability, DNA damage and stress related enzymes. Similar alterations could also be found in signalling protein cascade in L6 cells in response to treatment of 5 μg/ml NPG against CM-induced toxicity and depletion of overall ROS generation and nuclear condensation. Therefore, NPG could be used as a potential drug in management of pesticide toxicity in cultured edible fish.

Investigation of toxic effects of amorphous SiO2 nanoparticles on motility and oxidative stress markers in rainbow trout sperm cells

In this study, we investigated the effects of SiO₂ nanoparticles (SiO₂-NPs) (1, 10, 25, 50, and 100 mg/L) for 24 h in vitro on the motility parameters and oxidative stress markers such as total glutathione (TGSH), catalase (CAT), and malondialdehyde (MDA) of rainbow trout, Oncorhynchus mykiss sperm cells. Therefore, SiO₂-NPs were synthesized with sol-gel reaction from tetraethoxy orthosilicate (TEOS). The prepared nanoparticle structures were characterized for chemical structure, morphology and thermal behavior employing Fourier transform infrared spectroscopy, X-ray spectroscopy, scanning electron micrograph, and thermal analysis (DTA/TGA/DSC) techniques. After exposure, there was statistically significant (p < 0.05) decreases in velocities of sperm cells. CAT activity significantly (p < 0.05) decreased by 9.6% in sperm cell treated with 100 mg/L. In addition, MDA level significantly increased by 70.4% and 77.5% in sperm cell treated with 50 and 100 mg/L SiO₂-NPs, respectively (p < 0.05). These results showed that SiO₂-NPs may have toxic effect on rainbow trout sperm cells in 50 mg/L and more.

Devil's hand conceals behind the obscure side of AgNPs: A letter to the editor

From that time AgNPs become one of the most accessible and important antibacterial agents in our world, thousands of papers published regarding investigating all aspects of these materials. When the time elapsed and novel methods contrived to follow the fingerprint of AgNPs in the in vivo models, some critical concerns and arguments also appeared between researchers about the safety of these compounds for living cells and vital organs. The paper by Dehvari and Ghahaghaei published in Volume 108 International Journal of Biological Macromolecules, pages 1128-1139 (Dehvari and Ghahghaei, 2018) suffered some errors from safety concerns to obscurities in the results essentially needing the amendment to enhance its quality. Though the author(s) idea is commended enough, nevertheless, I could not find a profound trace with their results, and my concerns are discussed in detail as the following lines.

Assessment of acute toxicity and cytotoxicity of fluorescent markers produced by cardanol and glycerol, which are industrial waste, to different biological models

The amphyphylic triazoanilines recently synthesized 1-(4-(3-aminophenyl)-1H-1,2,3- triazole-1-yl)-3-(3-pentadecylphenoxy)propan-2-ol (1) and 1-(4-(4-aminophenyl)-1H- 1,2,3-triazole-1-yl)-3-(3-pentadecylphenoxy)propan-2-ol (2), synthesized from cardanol and glycerol, have photophysical properties which allow their use in the development of fluorescent biomarkers with applicability in the biodiesel quality control. Based on this, the present research evaluated the toxic effects of both compounds in different biological models through the investigation of survival and mortality percentages as a measure of acute toxicity on Daphnia similis and Oreochromis niloticus, larvicidal assay against Aedes aegypti, and cytotoxic activity on mammary cells. Results demonstrate that these triazoanilines 1 and 2 have shown low acute toxicity to the biological models investigated in this study up to the following concentrations: 4.0 mg L-1 (D. similis), 4.0 mg L-1 (A. aegypti larvae), 1.0 mg L-1 (O. niloticus), and 1.0 mg mL-1 (mammary cells). This fact suggests the potential for safe use of compounds 1 and 2 as fluorescent markers for the monitoring of biodiesel quality, even in the case of environmental exposure. Besides all of that, the reuse of cardanol and glycerol, both industrial wastes, favors the maintenance of environmental health and is in agreement with the assumptions of green chemistry. Graphical abstract ᅟ.

Vitamins E and C ameliorate the oxidative stresses induced by zinc oxide nanoparticles on liver and gills of Oreochromis niloticus

The current study evaluated the hazards of Zinc oxide nanoparticles (ZnONPs) on Nile Tilapia liver and gill antioxidants enzymes activities and antioxidants genes expressions. The ameliorative action of vitamins E and C mixture was investigated. Two hundred males of Nile Tilapia were exposed to one and two mg L-1 of ZnONPs either with or without vitamin C and E mixture for 7 and 15 days. Glutathione reductase (GR), glutathione peroxidase (GPx) and glutathione-S-transferase (GST) activities and gene expression as well glutathione (GSH) and lipid peroxide (LPO) levels were investigated. The results revealed that the exposure to ZnONPs could induce alterations in the liver and gills antioxidants and LPO of Nile Tilapia. Moreover, the mixture of vitamin E and C highly effective in alleviation the toxic effect of ZnONPs.

Neurotoxicity, behavioral changes and gene-expression profile of mice exposed to SnS2 nanoflowers

Recently, interest in the potential applications of tin disulphide nanoflowers (SnS2 NFs) in the treatment of waste water and their antibacterial properties has increased. However, their effects on neurotoxicity, brain cognition and behavioural injury, as well as the underlying mechanisms of these effects have remained unknown. In the present study, we compared the neurotoxicity of SnS2 NFs (50 nm) administered intragastrically at different doses (5, 10, and 50 mg kg-1) in mice for 60 days. The results showed that the neurotoxicity of SnS2 NFs in mice is dose-dependent. Furthermore, expression levels of genes related to oxidative stress, metabolism and signal transduction were also modified in the brain tissues of mice exposed to SnS2 NFs, supporting the SnS2 NF-dependent neurotoxic phenotype. Additionally, SnS2 NF exposure resulted in an abnormal ultrastructure in the hippocampus of the treated mice. Nevertheless, their body weight, organ coefficient and behaviour assessed in an open-field test and learning and memory test results assessed using a Morris water maze test remained unaffected. This suggested that the increased risk of neurotoxicity in SnS2 NF-treated mice was dependent on the dosage of SnS2 NFs. The relative level of safety was <5 mg kg-1 for 50 nm SnS2 NFs. The present study provides an experimental basis for the safe application of SnS2 NFs; however, chronic behavioural effects of SnS2 NFs remain unknown.

The Toxicity Assessment of Iron Oxide (Fe₃O₄) Nanoparticles on Physical and Biochemical Quality of Rainbow Trout Spermatozoon

The aim of this study was to evaluate the in vitro effect of different doses (50, 100, 200, 400, and 800 mg/L) of Fe₃O₄ nanoparticles (NPs) at 4 °C for 24 h on the kinematics of rainbow trout (Oncorhynchus mykiss, Walbaum, 1792) spermatozoon. Firstly, Fe₃O₄ NPs were prepared at about 30 nm from Iron (III) chloride, Iron (II) chloride, and NH₃ via a co-precipitation synthesis technique. Then, the prepared Fe₃O₄ NPs were characterized by different instrumental techniques for their chemical structure, purity, morphology, surface properties, and thermal behavior. The size, microstructure, and morphology of the prepared Fe₃O₄ NPs were studied by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) spectroscopy, and scanning electron microscopy (SEM) equipped with an energy-dispersive X-ray spectrometer (EDS). The thermal properties of the Fe₃O₄ NPs were determined with thermogravimetric analysis (TGA), differential thermal analysis (DTA), and differential scanning calorimeter (DSC) analysis techniques. According to our results, there were statistically significant (p < 0.05) decreases in the velocities of spermatozoon after treatment with 400 mg/L Fe₃O₄ NPs. The superoxide dismutase (SOD) and catalase (CAT) activities were significant (p < 0.05) decrease after 100 mg/L in after exposure to Fe₃O₄ NPs in 24 h. As the doses of Fe₃O₄ NPs increases, the level of malondialdehyde (MDA) and total glutathione (tGSH) significantly (p < 0.05) increased at doses of 400 and 800 mg/L.

Synthesis of biogenic silver nanoparticles using Althaea officinalis as reducing agent: evaluation of toxicity and ecotoxicity

Silver nanoparticles (AgNPs) are known mainly because of their bactericidal properties. Among the different types of synthesis, there is the biogenic synthesis, which allows the synergy between the nanocomposites and substances from the organism employed for the synthesis. This study describes the synthesis of AgNPs using infusion of roots (AgNpR) and extract (AgNpE) of the plant Althaea officinalis. After the synthesis through reduction of silver nitrate with compounds of A. officinalis, physico-chemical analyzes were performed by UV-Vis spectroscopy, nanoparticles tracking analysis (NTA), dynamic light scattering (DLS) and scanning electron microscopy (SEM). Toxicity was evaluated through Allium cepa assay, comet test with cell lines, cell viability by mitochondrial activity and image cytometry and minimal inhibitory concentration on pathogenic microorganisms. Biochemical analyzes (CAT - catalase, GPx - glutathione peroxidase e GST - glutationa S-transferase) and genotoxicity evaluation in vivo on Zebrafish were also performed. AgNpE and AgNpR showed size of 157 ± 11 nm and 293 ± 12 nm, polydispersity of 0.47 ± 0.08 and 0.25 ± 0.01, and zeta potential of 20.4 ± 1.4 and 26.5 ± 1.2 mV, respectively. With regard to toxicity, the AgNpE were the most toxic when compared with AgNpR. Biochemical analyzes on fish showed increase of CAT activity in most of the organs, whereas GPx showed few changes and the activity of GST decreased. Also regarding to bactericidal activity, both nanoparticles were effective, however AgNpR showed greater activity. Althaea officinalis can be employed as reducing agent for the synthesis of silver nanoparticles, although it is necessary to consider its potential toxicity and ecotoxicity.