Adsorption of Cd to TiO2-NPs Forms Low Genotoxic AGGREGATES in Zebrafish Cells

MiR-495-3p regulates myoblasts proliferation and differentiation through targeting cadherin 2

MircoRNAs (miRNAs) play an important role in skeletal muscle development. Previous study had found that miR-495-3p was differentially expressed in fetal and adult goat skeletal muscle, but its function in myogenic proliferation and differentiation are unclear. Herein, we found the expression of miR-495-3p in C2C12 was downregulated during proliferation stage and upregulated during differentiation stage. Functionally, overexpression of miR-495-3p in C2C12 inhibited proliferation, and promoted myogenic differentiation. Mechanistically, the luciferase reporter assay demonstrated that cadherin 2 (CDH2) was a potential target gene of miR-495-3p. Importantly, overexpression of miR-495-3p inhibited CDH2 expression. Furthermore, knockdown of CDH2 in C2C12 inhibited proliferation and promoted myogenic differentiation. Together, the results showed that miR-495-3p inhibits C2C12 proliferation and promotes myogenic differentiation through targeting CDH2.

Single and combined genotoxicity of metals and fluoroquinolones to zebrafish embryos at environmentally relevant concentrations

Fluoroquinolones (FQs) are known to have genotoxicity to aquatic organisms. However, their genotoxicity mechanisms, individually and in combination with heavy metals, are poorly understood. Here, we investigated the single and joint genotoxicity of FQs, ciprofloxacin (CIP) and enrofloxacin (ENR), and metals (Cd and Cu) at environmentally relevant concentrations (0.2 µM) to zebrafish embryos. We found that FQs or/and metals induced genotoxicity (i.e., DNA damage and cell apoptosis) to zebrafish embryos. Compared with their single exposure, the combined exposure of FQs and metals elicited less ROS overproduction but higher genotoxicity, suggesting other toxicity mechanisms may also act in addition to oxidation stress. The upregulation of nucleic acid metabolites and the dysregulation of proteins confirmed the occurrence of DNA damage and apoptosis, and further revealed the inhibition of DNA repair by Cd and binding of DNA or DNA topoisomerase by FQs. This study deepens the knowledge on the responses of zebrafish embryos to exposure of multiple pollutants, and highlights the genotoxicity of FQs and heavy metals to aquatic organisms.

TiO2-NPs and cadmium co-exposure: in vitro assessment of genetic and genomic DNA damage on Dicentrarchus labrax embryonic cells

The increased titanium dioxide nanoparticles (TiO₂-NPs) spread and their interaction with organic and inorganic pollutants arouses concern for the potential hazards for organisms and environment. This study tested in vitro the genotoxic effects of TiO₂-NPs (1 μg/mL) and cadmium (Cd) (0.1 μg/mL) co-exposure using Dicentrarchus labrax embryonic cells (DLEC) as experimental model. The genotoxicity tests (Comet assay, Diffusion Assay and Random Amplification of Polymorphic DNA (RAPD-PCR) were conducted after 3, 24 and 48 hours of exposure to TiO₂-NPs and Cd alone and in combination. The results showed that the percentage of DNA damage and apoptotic cells increases following 48 hours TiO₂-NPs exposure, while DNA instability was detected for all the times tested. Cd induced genotoxic effects starting from 3 hour-exposure and for all the treatment times. Cd + TiO₂-NPs co-exposure did not cause any genomic damage or apoptosis for all the exposure times. The possibility that Cd and TiO₂-NPs form aggregates no longer able of penetrating the nucleus and damaging the genetic material is discussed.

Cytoprotective and Antigenotoxic Properties of Organic vs. Conventional Tomato Puree: Evidence in Zebrafish Model

In this in vivo study, we investigated cytoprotective and antigenotoxic effects of commercial tomato puree obtained from conventional vs. organic farming systems (pesticides vs. pesticide-free agriculture, respectively). This is relevant as pesticides are widely used in agriculture to prevent pests, weeds, and the spread of plant pathogens. By exposing zebrafish to tomato puree alone and in combination with H2O2 (a well-known genotoxic agent), we analyzed the percentage of fish survival, cell viability, intracellular concentration of reactive oxygen species (ROS), DNA fragmentation index (DFI%), and genomic template stability (GTS%). Fish exposed to organic puree showed higher fish survival and cellular viability, lower DFI% and ROS, and improved GTS%. Our results suggest a higher cytoprotective and antigenotoxic effect of organic pesticide-free tomatoes, probably because the activity of natural phytochemicals is not affected by the presence of toxic residues, which are otherwise produced by pesticides used in conventional farming systems. Our study points out the importance of considering alternative strategies in agriculture to minimize the genotoxic impact of chemical pesticides.

Evaluation of Zebrafish DNA Integrity after Individual and Combined Exposure to TiO2 Nanoparticles and Lincomycin

Environmental contamination by nanoparticles (NPs) and drugs represents one of the most debated issues of the last years. The aquatic biome and, indirectly, human health are strongly influenced by the negative effects induced by the widespread presence of pharmaceutical products in wastewater, mainly due to the massive use of antibiotics and inefficient treatment of the waters. The present study aimed to evaluate the harmful consequences due to exposure to antibiotics and NPs, alone and in combination, in the aquatic environment. By exploiting some of their peculiar characteristics, such as small size and ability to bind different types of substances, NPs can carry drugs into the body, showing potential genotoxic effects. The research was conducted on zebrafish (Danio rerio) exposed in vivo to lincomycin (100 mg/L) and titanium dioxide nanoparticles (TiO₂ NPs) (10 µg/L) for 7 and 14 exposure days. The effects on zebrafish were evaluated in terms of cell viability, DNA fragmentation, and genomic template stability (GTS%) investigated using Trypan blue staining, TUNEL assay, and the random amplification of polymorphic DNA PCR (RAPD PCR) technique, respectively. Our results show that after TiO₂ NPs exposure, as well as after TiO₂ NPs and lincomycin co-exposure, the percentage of damaged DNA significantly increased and cell viability decreased. On the contrary, exposure to lincomycin alone caused only a GTS% reduction after 14 exposure days. Therefore, the results allow us to assert that genotoxic effect in target cells could be through a synergistic effect, also potentially mediated by the establishment of intermolecular interactions between lincomycin and TiO₂ NPs.

Anti-Genotoxicity Evaluation of Ellagic Acid and Curcumin—An In Vitro Study on Zebrafish Blood Cells

Genotoxicity is the ability of specific substances to cause DNA damage, affecting development, physiology, and reproduction. This is often mediated by induction of oxidative stress. This in vitro study aims to test the ability of two antioxidants, ellagic acid (EA, 100 µM) and curcumin (Cur, 40 µM) to protect zebrafish blood cells from the genotoxic action of benzene (10 µL/mL). Cells were treated for 30, 60, and 90 min with EA or Cur alone and in combination with benzene. The antigenotoxic role of antioxidants was evaluated in terms of cytotoxicity by trypan blue dye, genome stability by RAPD-PCR technique, DNA fragmentation and percentage of apoptotic cells using Comet and Diffusion assay, respectively. The results did not show statistical differences in terms of cell viability, genome stability, DNA damage and apoptosis between cells treated with antioxidants. When zebrafish blood cells were co-incubated with individual antioxidants and benzene, a significant improvement of these parameters was observed in comparison with cells incubated in benzene. Our results suggested that EA and Cur are able to protect zebrafish blood cells against DNA damage and apoptosis caused by mutagenic substance, and laid the foundation for future studies investigating their antigenotoxic potential in DNA oxidative damage therapy.