Neurotoxicity of Chronic Co-Exposure of Lead and Ionic Liquid in Common Carp: Synergistic or Antagonistic?

Ionic liquids and their potential use in development and improvement of drug delivery systems: evidence of their tendency to promote drug accumulation in the brain

Ionic liquids (ILs) are considered salt in liquid state, which is composed of organic cations and anions with low melting points (<100 °C). ILs have become a major scientific area with an extensive range of applications including chemistry, electrochemistry, and pharmaceutics. ILs have received great research interest in the pharmaceutical field as solvents, anti-solvents, co-solvents, and reagents in synthesis and formulation. While therapeutic ILs have been investigated for oral and trans-dermal drug delivery systems showing promising compatibility with a wide range of therapeutics, enhanced drug permeation through the skin, and cell membrane solvation to open channels to facilitate molecular passage, their potential to cross the challenging blood-brain barrier (BBB) remains an unanswered question. IL-based therapies could potentially be a game changer for improving drug delivery to cellular targets both at and across the BBB. In this review, we discuss (1) the tunable physicochemical properties of ILs; (2) the vast and various applications of ILs in the development and improvement of drug delivery systems; and (3) ILs as a potential approach for increasing drug accumulation in the brain tissue.

Subcellular effects of imidazolium-based ionic liquids with varying anions on the marine bivalve Mytilus galloprovincialis

Green Chemistry involves applying a set of principles aimed at minimizing the use of hazardous substances in the design, production, and application of chemical products. In recent decades, Ionic Liquids (ILs) have emerged as more environmentally friendly substitutes for traditional organic solvents. This preference is primarily due to their low vapor pressure, which results in minimal atmospheric pollution and enhanced industrial safety. However, existing literature highlights the toxicity of ILs towards aquatic invertebrates. Consequently, this study points to assess the biochemical effects of a selection of ILs through an in vitro approach. Specifically, digestive gland and gill cellular fractions (S9) of the marine bivalve Mytilus galloprovincialis were exposed to varying concentrations (0.05-2 μM) of three ILs featuring identical cations but different anions. The ILs tested were 1-ethyl-3-methylimidazolium octanoate ([EMIM][Oct]), 1-ethyl-3-methylimidazolium acetate ([EMIM][OAc]), and 1-ethyl-3-methylimidazolium ethyl sulfate ([EMIM][EtSO4]). The results indicate that [EMIM][Oct] induces higher toxicity in both S9 tissues, highlighting a strong effect of the anion. Overall, antioxidant and biotransformation defenses were significantly altered for all three ILs assessed. While acetylcholinesterase activity was significantly inhibited of about half of control activity, indicating neurotoxic damage as part of the toxicity mode of action of these ILs, neither lipid peroxidation nor alterations to DNA integrity were observed (≥100 %). This study supports the use of in vitro techniques as important tools capable of generating reliable ecotoxicological data, which can be further considered as a screening before in vivo testing and used for in silico modeling.

Exposure to environmentally relevant concentrations of Bisphenol-A linked to loss of visual lateralization in adult zebrafish (Danio rerio)

Weak, but environmentally relevant concentrations of contaminants can have subtle, yet important, impacts on organisms, which are often overlooked due to the lack of acute impacts and the timing of exposure. Thus, recognizing simple, non-invasive markers of contamination events is essential for early detection and addressing the effects of exposure to weak environmental contaminants. Here, we tested whether exposure to an environmentally relevant concentration of Bisphenol-A (BPA), a common and persistent contaminant in aquatic systems, affects the lateralization of adult zebrafish (Danio rerio), a widely used model organism in ecotoxicology. We found that 73.5% of adult zebrafish displayed a left-side bias when they approached a visual cue, but that those exposed to weak BPA (0.02 mg/L) for 7 days did not exhibit laterality. Only 47.1% displayed a left-side bias. We found no differences in activity level and visual sensitivity, motor and sensory mechanisms, that regulate lateralized responses and that were unaffected by weak BPA exposure. These findings indicate the reliability of laterality as a simple measure of contaminant exposure and for future studies of the detailed mechanisms underlying subtle and complex behavioral effects to pollutants.

The concentration and prevalence of potentially toxic elements (PTEs) in cheese: a global systematic review and meta-analysis

The present study aimed to systematically review the concentration of different PTEs, including Arsenic (As), Mercury (Hg), Lead (Pb), and Cadmium (Cd) in cheese among some databases between 2000 and 2021 (from 57 included studies). Estimated concentrations of 160.78 (95% CI = 119.24-202.28), 15.68 (95% CI = 11.88-19.48), 16.94 (95% CI = 13.29-20.59), and 2.47 (95% CI = 1.70-3.23) µg/kg were calculated for As, Pb, Cd, and Hg, respectively. Most of the studies for PTEs are related to Pb, about 40% of the studies, compared to As, which has fewer studies. The results showed that As and Hg concentrations were lower than the Codex Alimentarius Commission standard limits. Nevertheless, Cd and Pb concentrations were higher than the standard limit values. Results showed that cheese making, the ripening period, fat content, and texture are influential factors in a high level of Pb and Cd in cheese samples.

Fenpropathrin induces neurotoxic effects in common carp (Cyprinus carpio L.)

Fenpropathrin (FEN) is a synthetic pyrethroid that has been frequently detected in aquatic environments, yet the neurotoxic impacts and underlying mechanisms on nontarget organisms are lacking. In this experiment, common carp were exposed to 0.45 and 1.35 μg/L FEN for 14 d and exhibited abnormal locomotor behaviour. Biochemical and molecular analysis results indicated that FEN altered the contents of tight junction proteins (claudin-1, occludin, and ZO-1), disturbed Na+-K+-ATPase and AChE activities, caused abnormal expression of neurotransmitters (ACh, DA, GABA, 5-HT, and glutamate) and caused histological damage in the brain, suggesting that FEN may damage the blood-brain barrier and induce neurotoxicity in carp. Furthermore, FEN also promoted an increase in ROS, changed SOD and CAT activities, and generally upregulated the contents of MDA, 8-OHdG, and protein carbonyl in the brain, indicating that FEN can induce oxidative stress and cause damage to lipids, DNA, and proteins. Moreover, inflammation-related indicators (TNF-α, IL-1β, IL-6, and IL-10), mitophagy-related genes (PINK1, parkin, ulk1, beclin1, LC3, p62, tfeb, and atg5), and apoptosis-related parameters (p53, bax, bcl-2, caspase-3, caspase-8, and caspase-9) were also significantly changed, suggesting that inflammation, mitophagy, and apoptosis may participate in FEN-induced neurotoxicity in carp. This study refines the understanding of the toxicity mechanism of FEN and thus provides data support for the risk assessment of FEN.

Environmentally relevant concentrations of Mn2+ disrupts the endocrine regulation of growth in juvenile Yunlong groupers (Epinephelus moara♀×Epinephelus lanceolatus♂)

Even though manganese is a bioelement essential for metabolism, excessive manganese levels in water can be detrimental to fish development and growth. Therefore, the aim of this study was to evaluate the effects of Mn2+ (0, 0.5,1, 2, and 4 mg·L-1) exposure for 30 d on the growth performance, growth hormone/insulin-like growth factor (GH/IGF) axis, hypothalamic-pituitary-thyroid (HPT) axis, and monoaminergic neurotransmitters of Epinephelus moara♀×Epinephelus lanceolatus♂(Yunlong grouper). Compared with the control and low Mn2+concentration groups of (0.5 and 1 mg·L-1), the high concentration of Mn2+ (4 mg·L-1) significantly reduced body weight (BW), body length (BL), weight gain rate (WGR), and specific growth rate (SGR), increased the feed coefficient rate (FCR) and mortality of Yunlong groupers (P < 0.05). Further, the levels of GH and IGF, along with the expression of ghra and ghrb were significantly reduced after exposure to 2 and 4 mg·L-1 Mn2+for 30 d, whereas the expression of sst5 was significantly up-regulated after exposure to 2 and 4 mg·L-1 Mn2+for 20 and 30 days. Moreover, Mn2+exposure increased thyroid hormone (T3) and thyroid stimulating hormone (TSH) contents, accompanied by increased mRNA levels of dio1 and dio2, however, the T4 level was decreased. Finally, dopamine (DA) and serotonin (5-HT) levels significantly decreased after long-term exposure to higher concentrations of Mn2+, and the levels their metabolites changed as well, suggesting that the synthesis and metabolism of DA and 5-HT were affected. Accordingly, changes in the GH/IGF and HPT axes-related parameters may be the cause of growth inhibition in juvenile groupers under Mn2+ exposure, indicating that the relationship between endocrine disorder and growth inhibition should not be ignored.

Effects of Single and Combined Ciprofloxacin and Lead Treatments on Zebrafish Behavior, Oxidative Stress, and Elements Content

Even though the toxic effects of antibiotics and heavy metals have been extensively studied in the last decades, their combined adverse impact on aquatic organisms is poorly understood. Therefore, the objective of this study was to assess the acute effects of a ciprofloxacin (Cipro) and lead (Pb) mixture on the 3D swimming behavior, acetylcholinesterase (AChE) activity, lipid peroxidation level (MDA-malondialdehyde), activity of some oxidative stress markers (SOD-superoxide dismutase and GPx-glutathione peroxidase), and the essential elements content (Cu-copper, Zn-zinc, Fe-iron, Ca-calcium, Mg-magnesium, Na-sodium and K-potassium) in the body of zebrafish (Danio rerio). For this purpose, zebrafish were exposed to environmentally relevant concentrations of Cipro, Pb, and a mixture for 96 h. The results revealed that acute exposure to Pb alone and in mixture with Cipro impaired zebrafish exploratory behavior by decreasing swimming activity and elevating freezing duration. Moreover, significant deficiencies of Ca, K, Mg, and Na contents, as well as an excess of Zn level, were observed in fish tissues after exposure to the binary mixture. Likewise, the combined treatment with Pb and Cipro inhibited the activity of AChE and increased the GPx activity and MDA level. The mixture produced more damage in all studied endpoints, while Cipro had no significant effect. The findings highlight that the simultaneous presence of antibiotics and heavy metals in the environment can pose a threat to the health of living organisms.

The Differential Antagonistic Ability of Curcumin against Cytotoxicity and Genotoxicity Induced by Distinct Heavy Metals

Widespread heavy metal pollution has aroused severe health risks worldwide. Curcumin has been reported to play a wide-spectrum protective role for various heavy metals. However, the specificity and difference in the antagonistic ability of curcumin against distinct types of heavy metals are still largely unknown. Here, using cadmium (Cd), arsenic (As), lead (Pb), and nickel (Ni) as the typical heavy metals, we systematically compared the detoxification efficiency of curcumin on the cytotoxicity and genotoxicity elicited by different heavy metals under the same experimental conditions. Curcumin was proved to have a significant discrepant antagonistic capacity when counteracting the adverse effect of different heavy metals. Stronger protective effects of curcumin emerged when antagonizing the toxicity of Cd and As, rather than Pb and Ni. Curcumin exhibits a better detoxification ability against heavy metal-induced genotoxicity than cytotoxicity. Mechanistically, inhibiting the oxidative stress elicited by heavy metals and reducing the bioaccumulation of metal ions both contributed to the detoxification of curcumin against all the tested heavy metals. Our results illustrated that curcumin shows prominent detoxification specificity against different types of heavy metals and toxic endpoints, which provides a new clue for the better and targeted application of curcumin in heavy metal detoxification.