Effects of Co-Exposure of Nanoparticles and Metals on Different Organisms: A Review

Combined toxicity of fluorescent silica nanoparticles with cadmium in Ceriodaphnia dubia: Interactive effects of natural organic matter and green algae feeding

The environmental risks of silica nanoparticles (SiNP) reported in the literature are contradictory and bring into question its safety for use in consumer applications. Organisms are never exposed to NPs alone in the real environment, while studies of the combined toxicity of SiNP are limited. To address this, we compared the acute toxicity of fluorescent core-shell SiNPs alone and in mixtures with Cd2+ to Ceriodaphnia dubia in the absence and presence of NOM. We identified biodistribution and feeding behaviour in addition to the traditional endpoints. NOM increased the colloidal stability of SiNPs in reconstituted water. In immobility tests, no significant effects were observed from Cd2+ exposure with NOM and varying concentrations of SiNPs. A similar pattern of curve dose-response was observed for varying concentrations of SiNPs and increasing Cd2+ concentration and constant NOM. Fluorescence microscopy verified a dose-dependent bioaccumulation of SiNPs in C. dubia. Co-exposure to 10 mg L-1 SiNP with NOM and Cd2+ resulted in a stimulated stress feeding response at the lower Cd2+ concentrations which declined at the higher dose due to a functional impairment of the digestive tract. Alterations in feeding behaviour and the increasing bioaccumulation of SiNP indicate a potential ecological risk for Ceriodaphnia dubia from the mixture exposure.

Interactive effects of cadmium and titanium dioxide nanoparticles on hepatic tissue in rats: Ameliorative role of coenzyme 10 via modulation of the NF-κB and TNFα pathway

This study investigated the effect of oral dosing of titanium dioxide nanoparticles (TNPs) and cadmium (Cd2+) on rat liver and the potential protective role of coenzyme Q10 (CQ10) against TNPs and Cd2+-induced hepatic injury. Seventy male Sprague Dawley rats were divided into seven groups and orally given distilled water, corn oil, CQ10 (10 mg/kg b.wt), TNPs (50 mg/kg b.wt), Cd2+ (5 mg/kg b.wt), TNPs + Cd2+, or TNPs + Cd2++CQ10 by gastric gavage for 60 successive days. The results showed that individual or mutual exposure to TNPs and Cd2+ significantly increased the serum levels of various hepatic enzymes and lipids, depleted the hepatic content of antioxidant enzymes, and increased malondialdehyde. Moreover, the hepatic titanium and Cd2+ content were increased considerably in TNPs and/or Cd2+-exposed rats. Furthermore, marked histopathological perturbations with increased immunoexpression of tumor necrosis factor-alpha and nuclear factor kappa B were evident in TNPs and/or Cd2+-exposed rats. However, CQ10 significantly counteracted the damaging effect of combined exposure of TNPs and Cd2+ on the liver. The study concluded that TNPs and Cd2+ exposure harm hepatic function and its architecture, particularly at their mutual exposure, but CQ10 could be a candidate protective agent against TNPs and Cd2+ hepatotoxic impacts.

Glabridin mitigates TiO2NP induced cognitive deficit in adult zebrafish

Glabridin is extracted from the roots of Glycyrrhiza glabra, which has anti-oxidative and anti-inflammatory properties. We investigated the neuroprotective potential of Glabridin against the learning and memory deficit by triggering NRF2/HO-1 signaling in Titanium dioxide nanoparticles (TiO2NP) treated zebrafish. Our study suggests that Glabridin at doses of 12.5, 25, and 50 mg/kg/day for 7 days improved memory and lowered anxiety in the novel object recognition test, T-maze, and novel diving tank respectively. Biochemical analysis showed that Glabridin treatment in TiO2NP-exposed zebrafish enhanced GSH, CAT, SOD, and GPx activity and reduced MDA levels; inhibited proinflammatory mediators, namely, TNF-α, IL-1β, and IL-6. In histopathological evaluation, Glabridin significantly reduced pycnotic neurons in TiO2NP-treated zebrafish brains. Furthermore, Glabridin upregulated NRF2 and HO-1 levels, which leads to a decline in oxidative stress and neuroinflammation and were reversed by ML385 treatment. ML385 as a probe molecule that specifically inhibit NRF2 and prevents its downstream gene expression. Thus, these considerable outcomes provide new insights into the neuroprotective effect of glabridin.

Response of moulting genes and gut microbiome to nano-plastics and copper in juvenile horseshoe crab Tachypleus tridentatus

Nanoplastics (NPs) and heavy metals are typical marine pollutants, affecting the gut microbiota composition and molting rate of marine organisms. Currently, there is a lack of research on the toxicological effects of combined exposure to horseshoe crabs. In this study, we investigated the effects of NPs and copper on the expression of molt-related genes and gut microbiome in juvenile tri-spine horseshoe crabs Tachypleus tridentatus by exposing them to NPs (100 nm, 104 particles L-1) and/or Cu2+ (10 μgL-1) in seawater for 21 days. Compared with the control group, the relative mRNA expression of ecdysone receptor (EcR), retinoid x receptor (RXR), calmodulin-A-like isoform X1 (CaM X1), and heat shock 70 kDa protein (Hsp70) were significantly increased under the combined stress of NPs and Cu2+. There were no significant differences in the diversity and abundance indices of the gut microbial population of horseshoe crabs between the NPs and/or Cu2+ groups and the control group. According to linear discriminant analysis, Oleobacillus was the most abundant microorganism in the NPs and Cu2+ stress groups. These results indicate that exposure to either NPs stress alone or combined NPs and Cu2+ stress can promote the expression levels of juvenile molting genes. NPs exposure has a greater impact on the gut microbial community structure of juvenile horseshoe crabs compared to Cu2+ exposure. This study is helpful for predicting the growth and development of horseshoe crabs under complex environmental pollution.

Restorative effects of gallic acid against sub-chronic hepatic toxicity of co-exposure to zinc oxide nanoparticles and arsenic trioxide in male rats

Background and objectives

This study aimed to assess the effect of zinc oxide nanoparticles (ZNPs) and/or arsenic trioxide (ATO) exposure on the liver of adult male Sprague Dawley rats. Moreover, the probable ameliorative impact of gallic acid (GA) against ZNPs and ATO-induced hepatotoxicity and the possible underlying mechanisms were evaluated.

Methods

Sixty male Sprague Dawley rats were distributed into six groups. The 1^st and 2^nd groups were orally given distilled water (1 ml/kg) and 20 mg GA/kg b. wt, respectively. The 3^rd and 4^th groups were orally given 100 mg ZNPs/kg b. wt and 8 mg ATO/kg b. wt, respectively. The 5^th group was co-administered ZNPs and ATO at the doses mentioned above. The last one was co-administered ZNPs, ATO, and GA at the earlier described doses. All tested compounds were orally given once a day for 60 successive days. Then, serum levels of alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), total, direct, indirect bilirubin, triglycerides, total cholesterol, HDL, VLDL, and LDL were estimated. The hepatic content of malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GPx) was evaluated. Moreover, Bcl-2 and Bax's reactive proteins were immunohistochemically detected, and Zn and As residual patterns in hepatic tissues were assessed.

Results

ZNPs, ATO, and ZNPs+ATO-exposed rats showed significantly (P < 0.001) elevated serum AST (219%, 233%, and 333%), ALT (300%, 400%, and 475%), ALP (169%, 205%, and 294%), and total bilirubin (42%, 68%, and 109%) compared to the control ones. On the other hand, a significantly (P < 0.001) declined SOD (58%, 49%, and 43%) and GPx (70%, 63%, and 56%) but increased MDA (133%, 150%, and 224%) was recorded in the hepatic tissues of ZNPs, ATO, and ZNPs+ATO exposed rats, respectively, relative to the control rats. Moreover, the hepatic tissues of the ZNPs, ATO, and ZNPs+ATO exposed rats showed a significant (P < 0.001) decrease in Bcl-2 (28%, 33%, and 23%) but elevation in Bax (217%, 267%, and 236%) immunoreactivities compared to the control rats. These findings were consistent with the microscopic alterations in the hepatic architecture and accumulation of Zn and As. Furthermore, a notable hyperlipidemic condition was recorded following ZNPs and/or ATO exposure. On the contrary, GA notably reduced hepatic enzymes compared to ZNPs+ATO-exposed rats. Additionally, GA markedly improved ZNPs+ATO-afforded liver tissue damage and apoptotic events.

Conclusion

Overall, GA oral dosing significantly mitigated the negative effects of ZNPs and ATO on the liver by improving the antioxidant defense system and controlling apoptotic changes.

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

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

Quercetin Abates Aluminum Trioxide Nanoparticles and Lead Acetate Induced Altered Sperm Quality, Testicular Oxidative Damage, and Sexual Hormones Disruption in Male Rats

This study examined the effects of exposure to lead acetate (PbAc) and/or aluminum trioxide nanoparticles (Al₂O₃NPs) on testicular function. Additionally, the probable reproprotective effects of quercetin (QTN) against Al₂O₃NPs and PbAc co-exposure in male Sprague Dawely rats were assessed. Al₂O₃NPs (100 mg/kg b.wt.), PbAc (50 mg/kg b.wt.), and QTN (20 mg/kg b.wt.) were orally administered for 60 days. Then, spermiogram, histopathological examinations of the testis and accessory glands, and immunohistochemical detection of androgen receptors (AR) and tumor necrotic factor alpha (TNF-α) were achieved. Moreover, serum levels of male sex hormones and testicular levels of antioxidant indices were estimated. The results showed that Al₂O₃NP_s and/or PbAc caused significant sperm abnormalities, testicular oxidative stress, and histopathological changes. Furthermore, serum testosterone, LH, and FSH levels significantly decreased, while estradiol levels significantly increased. The Al₂O₃NPs and/or PbAc co-exposed group had more obvious disturbances. Furthermore, QTN co-administration significantly reversed the Al₂O₃NPs and PbAc-induced testicular histopathological alterations, reduced antioxidant defenses, and altered AR and TNF-α immune expression in testicular tissues. Conclusively, Al₂O₃NPs and/or PbAc evoked testicular dysfunction by inducing oxidative injury and inflammation. However, QTN oral dosing effectively mitigated the negative effects of Al₂O₃NPs and PbAc by suppressing oxidative stress and inflammation and improving the antioxidant defense system.

Palliative Effect of Resveratrol against Nanosized Iron Oxide-Induced Oxidative Stress and Steroidogenesis-Related Genes Dysregulation in Testicular Tissue of Adult Male Rats

The nano-sized iron oxide (Fe₂O₃-NPs) is one of the most used engineered nanomaterials worldwide. This study investigated the efficacy of natural polyphenol resveratrol (RSV) (20 mg/kg b.wt, orally once daily) to alleviate the impaired sperm quality and testicular injury resulting from Fe₂O₃-NPs exposure (3.5 or 7 mg/kg b.wt, intraperitoneally once a week) for eight weeks. Spermiograms, sexual hormonal levels, oxidative stress indicators, and lipid peroxidation biomarker were assessed. Moreover, the steroidogenesis-related genes mRNA expressions were evaluated. The results showed that RSV substantially rescued Fe₂O₃-NPs-mediated sperm defects. Additionally, the Fe₂O₃-NPs-induced depressing effects on sperm motility and viability were markedly counteracted by RSV. Moreover, RSV significantly restored Fe₂O₃-NPs-induced depletion of testosterone, follicle-stimulated hormone, luteinizing hormone, and testicular antioxidant enzymes but reduced malondialdehyde content. Furthermore, the Fe₂O₃-NPs-induced downregulation of steroidogenesis-related genes (3 β-HSD, 17 β-HSD, and Nr5A1) was significantly counteracted in the testicular tissue of RSV-treated rats. These findings concluded that RSV could limit the Fe₂O₃-NPs-induced reduced sperm quality and testicular injury most likely via their antioxidant activity and steroidogenesis-related gene expression modulation.