Region-specific DNA alterations in focally induced seizures

GAT inhibition preserves cerebral blood flow and reduces oxidant damage to mitochondria in rodents exposed to extreme hyperbaric oxygen

Oxygen breathing at elevated partial pressures (PO₂'s) at or more than 3 atmospheres absolute (ATA) causes a reduction in brain γ-aminobutyric acid (GABA) levels that impacts the development of central nervous system oxygen toxicity (CNS-OT). Drugs that increase brain GABA content delay the onset of CNS-OT, but it is unknown if oxidant damage is lessened because brain tissue PO₂ remains elevated during hyperbaric oxygen (HBO₂) exposures. Experiments were performed in rats and mice to measure brain GABA levels with or without GABA transporter inhibitors (GATs) and its influence on cerebral blood flow, oxidant damage, and aspects of mitochondrial quality control signaling (mitophagy and biogenesis). In rats pretreated with tiagabine (GAT1 inhibitor), the tachycardia, secondary rise in mean arterial blood pressure, and cerebral hyperemia were prevented during HBO₂ at 5 and 6 ATA. Tiagabine and the nonselective GAT inhibitor nipecotic acid similarly extended HBO₂ seizure latencies. In mice pretreated with tiagabine and exposed to HBO₂ at 5 ATA, nuclear and mitochondrial DNA oxidation and astrocytosis was attenuated in the cerebellum and hippocampus. Less oxidant injury in these regions was accompanied by reduced conjugated microtubule-associated protein 1A/1B-light chain 3 (LC3-II), an index of mitophagy, and phosphorylated cAMP response element binding protein (pCREB), an initiator of mitochondrial biogenesis. We conclude that GABA prevents cerebral hyperemia and delays neuroexcitation under extreme HBO₂, limiting oxidant damage in the cerebellum and hippocampus, and likely lowering mitophagy flux and initiation of pCREB-initiated mitochondrial biogenesis.

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.

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.

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

The aquatic environment is involved in the pollutants spreading mechanisms, including nanomaterials and heavy metals. The aims of this study were to assess the in vivo genotoxicity of Cd (1 mg/L) and to investigate the genomic effects generated by its co-exposure with TiO₂-NPs (10 µg/L). The study was performed using zebrafish as a model for 5, 7, 14, 21, and 28 days of exposure. The genotoxic potential was assessed by three experimental approaches: DNA integrity, degree of apoptosis, and molecular alterations at the genomic level by genomic template stability (% GTS) calculation. Results showed an increased in DNA damage after Cd exposure with a decrease in % GTS. The co-exposure (TiO₂-NPs + Cd) induced a no statistically significant loss of DNA integrity, a reduction of the apoptotic cell percentage and the recovery of genome stability for prolonged exposure days. Characterization and analytical determinations data showed Cd adsorption to TiO₂-NPs, which reduced free TiO₂-NPs levels. The results of our study suggest that TiO₂-NPs could be used for the development of controlled heavy metal bioremediation systems.

NPs-TiO2 and Lincomycin Coexposure Induces DNA Damage in Cultured Human Amniotic Cells

Titanium dioxide nanoparticles (NPs-TiO2 or TiO2-NPs) have been employed in many commercial products such as medicines, foods and cosmetics. TiO2-NPs are able to carry antibiotics to target cells enhancing the antimicrobial efficiency; so that these nanoparticles are generally used in antibiotic capsules, like lincomycin, added as a dye. Lincomycin is usually used to treat pregnancy bacterial vaginosis and its combination with TiO2-NPs arises questions on the potential effects on fetus health. This study investigated the potential impact of TiO2-NPs and lincomycin co-exposure on human amniocytes in vitro. Cytotoxicity was evaluated with trypan blue vitality test, while genotoxic damage was performed by Comet Test, Diffusion Assay and RAPD-PCR for 48 and 72 exposure hours. Lincomycin exposure produced no genotoxic effects on amniotic cells, instead, the TiO2-NPs exposure induced genotoxicity. TiO2-NPs and lincomycin co-exposure caused significant increase of DNA fragmentation, apoptosis and DNA damage in amniocytes starting from 48 exposure hours. These results contribute to monitor the use of TiO2-NPs combined with drugs in medical application. The potential impact of antibiotics with TiO2-NPs during pregnancy could be associated with adverse effects on embryo DNA. The use of nanomaterials in drugs formulation should be strictly controlled in order to minimize risks.

Anti-genotoxic ability of α-tocopherol and Anthocyanin to counteract fish DNA damage induced by musk xylene

Many compounds released into the environment are able to interact with genetic material. The main purpose of genetic toxicology is to investigate the adverse effects of genotoxic molecules such as reduced fitness, changes in gene frequencies and their impact on genetic diversity in populations following genotoxic exposure. However, the ecological effects of many genotoxic compounds remain poorly understood. The aim of this research was to evaluate the genotoxic activity of an artificial musk (musk xylene, MX) and the potential anti-genotoxicity against this chemical compound of two antioxidant substances (α-tocopherol and an anthocyanins enriched extract). The studies were performed both in vivo and in vitro, using the teleost Danio rerio and the DLEC (Dicentrarchus labrax embryonic cells) cell line. We carried out the exposure to these substances at different times. DNA and cell damage and their possible repair were detected by various experimental approaches: DNA strand breaks (Comet Assay), degree of apoptosis (Diffusion Assay) and molecular alterations at the genomic level (RAPD-PCR technique). Data were collected and analyzed for statistical significance using the Student's t test. The results of this study showed that MX exhibited a genotoxic activity even after short exposure times. The anti-genotoxicity experiments evidenced that both α-tocopherol and Anthocyanin were able to contrast the genotoxic effects induced by MX, both in vivo and in vitro.