Significant Increase In DNA Damage Research Articles

Designing and applying a methodology to assess sperm cell viability and DNA damage in a model amphipod

Sperm quality is defined as the sperm cell ability to successfully fertilize eggs and allow normal embryo development⁠. Few studies explore sperm quality using aquatic invertebrates. Parhyale hawaiensis is a marine amphipod with a circumtropical distribution and considered a model for evolution, development, and ecotoxicological studies. We aimed to develop a methodology to collect sperm cells of P. hawaiensis and evaluate their viability and DNA damage (comet assay). We directly exposed the sperm cells to different mutagenic agents to optimize/develop the protocols. Then, as a proof of concept, we exposed the males to mutagenic compounds (EMS, benzo[a]pyrene (BaP), azo and anthraquinone dyes) at non-lethal concentrations verified by the proposed viability test and analyzed their sperm cells for DNA damage (comet assay). Organisms exposed to EMS presented a clear concentration response in the DNA damage response. We also showed that BaP was able to induce a statistically significant increase in DNA damage of the sperm cells. For the two dyes, although DNA damage increased, statistically differences were not observed. We believe we successfully developed a test to detect genotoxicity of chemicals in sperm cells using an invertebrate model. The protocol for sperm cell viability needs to be further explored with different chemicals to verify its utility as a toxicity endpoint. The developed genotoxicity test has the advantages to employ organisms that are easily cultivated in reduced space, use simple laboratory resources and reduced amount of material and reagents. Positive responses with this model could be used to disclose new germ cell mutagen candidates which could be further confirmed in vertebrates' systems.

Protective efficacy of ramelteon on methotrexate-induced DNA damage

Ramelteon (RMLT) is a melatonin receptor agonist that it has antioxidative and anti-inflammatory effects associated with DNA damage through different mechanisms of action. In this regard, we investigated the potential usefulness of RMLT as a protective agent against methotrexate (MTX)-induced DNA damage. Four groups were constituted from 32 Wistar albino rats: Negative control, RMLT, MTX, and MTX + RMLT. Twenty mg/kg MTX (i.p., single dose) and RMLT 10 mg/kg (oral, 7 days) was administered. Comet assay was used and the parameter %TailDNA was used to detect DNA damage. %TailDNA was 4.90 ± 0.19 in the control group, 7.85 ± 0.33 in the MTX group, 5.49 ± 0.24 in the RMLT group, and 5.86 ± 0.23 in the MTX + RMLT group. While there was a significant increase in DNA damage in the MTX-treated group compared to the control group, there was a significant reduction in DNA damage in the MTX + RMLT group, compared to the MTX group (p < 0.001). In conclusion, it was observed that combined treatment with RMLT significantly reduced MTX-induced DNA damage.

Effects of low-dose gamma radiation on DNA measured using a quartz tuning fork sensor

Despite the expected direct effects of radiation on DNA through its direct interaction with the biomolecule, research indicates that radiation also interacts with the DNA’s environment, resulting in indirect effects Therefore, in this study, we explored the feasibility of using the quartz tuning fork (QTF) sensor system in biomedical applications, specifically in detecting DNA damage caused by low doses of gamma radiation, directly and indirectly. We differentiated between direct and indirect damage by analyzing the fork’s resonance frequency changes. This experiment was divided into three stages: before, during, and after irradiation. Each stage involved samples of pure DNA and DNA in a 60-µL aqueous solution, evaluated under identical conditions. Before irradiation, we measured frequency shifts (Δf) over a 20-min period, resulting in values of 19.34, 20.25, and 7.6 Hz for water, DNA, and DNA in water, respectively. Subsequently, the samples were irradiated with cesium-137 for the specified duration, resulting in frequency shifts of ∼ 39.21, 28.37, and 41.23 Hz for the same conditions. Our investigations showed an increase in Δf from 20.25 to 28.3 Hz at doses ranging from 7.5 to 30 µGy for pure DNA. Interestingly, DNA in aqueous solution exhibited hypersensitivity to radiation, with frequency shifts ranging from 7.6 to 41.23 Hz. Furthermore, we observed a significant difference in frequency shift after irradiation between pure DNA and DNA in water, with shifts of ∼ 70.75–98.45 Hz and 56.32–79.28 Hz for DNA and DNA in water, respectively. This result indicates a significant increase in DNA damage in aqueous environments, driven by the generation of active hydroxyl radicals (OH−), resulting in base damage and an associated increase in strand breaks. Consequently, our research indicates a lack of substantial direct impact on DNA repair owing to the absence of a conducive postirradiation environment. Therefore, QTF is a valuable biomarker for radiation sensitivity and is promising for future applications as a mass-sensitive biosensor.

Assessment of cellular senescence potential of PM2.5 using 3D human lung fibroblast spheroids in vitro model.

Epidemiological studies demonstrate that particulate matter 2.5 (PM2.5) exposure closely related to chronic respiratory diseases. Cellular senescence plays an important role in many diseases. However, it is not fully clear whether PM2.5 exposure could induce cellular senescence in the human lung. In this study, we generated a three-dimensional (3D) spheroid model using isolated primary human lung fibroblasts (HLFs) to investigate the effects of PM2.5 on cellular senescence at the 3D level. 3D spheroids were exposed to 25-100 μg/ml of PM2.5 in order to evaluate the impact on cellular senescence. SA-β-galactosidase activity, cell proliferation, and the expression of key genes and proteins were detected. Exposure of the HLF spheroids to PM2.5 yielded a more sensitive cytotoxicity than 2D HLF cell culture. Importantly, PM2.5 exposure induced the rapid progression of cellular senescence in 3D HLF spheroids, with a dramatically increased SA-β-Gal activity. In exploiting the mechanism underlying the effect of PM2.5 on senescence, we found a significant increase of DNA damage, upregulation of p21 protein levels, and suppression of cell proliferation in PM2.5-treated HLF spheroids. Moreover, PM2.5 exposure created a significant inflammatory response, which may be at least partially associated with the activation of TGF-β1/Smad3 axis and HMGB1 pathway. Our results indicate that PM2.5 could induce DNA damage, inflammation, and cellular senescence in 3D HLF spheroids, which may provide a new evidence for PM2.5 toxicity based on a 3D model which has been shown to be more in vivo-like in their phenotype and physiology than 2D cultures.

Abstract B035: Developing the UValidate platform to measure DNA damage and repair capacity in isogenic donor-derived skin keratinocytes, fibroblasts and melanocyte cell-lines with different Fitzpatrick phototypes

Abstract DNA damage associated with ultraviolet (UV) radiation exposure causes accelerated skin aging and cancer-initiating mutations. Over-the-counter UVA and UVB filters are required in all sunscreens, but transdermal absorption of these compounds have been reported to impair development and reproduction and metabolize into carcinogenic/mutagenic chemical intermediates. To assess the effects of sunscreen active ingredients on UVR-induced DNA damage and repair, we developed a novel high throughput (HTP) screening platform, UValidate, employing mixed populations of isogenic skin cells, exposed to single or combinations of UV filters in the presence of UVB and UVA. UValidate contains a patented LED UVR DNA damage induction system (LUDIS:V3), facilitating programmable precise induction of DNA damage and repair at multiple time points and replicates, using a 96-well configuration capable of simultaneous delivering UVA and UVB. LUDIS:V3 optimization experiments surprisingly revealed that, unlike keratinocytes, skin fibroblasts only repaired UVA DNA damage in conditioned media. We then tested sunscreen active ingredient combinations for their capacity to alter DNA repair and found that: 1) Some sunscreen ingredients, including dioxybenzone, induce a significant increase in DNA damage above endogenous levels. 2) Fibroblasts and keratinocytes respond differently to the treatment protocols. 3) Some sunscreen active compounds contribute to reduction of UVA-induced DNA damage. 4) No sunscreen completely inhibits all UVA DNA damage. We are currently employing the LUDIS:V3 system with HTP comet assays to compare DNA damage and DNA repair capacities, +/- sunscreen active ingredients, of six isogenic sets of primary epidermal keratinocytes (NHEK), melanocytes (NHEM), and fibroblasts (NHDF)` with different Fitzpatrick phototypes I-VI, representative of the diverse American population. These cells were isolated from donor skin samples, and further purified to establish banks of isogenic NHEK, NHEM, and NHDF cell lines. UVA exposure with the LUDIS:V3 and comet assays revealed higher levels of DNA damage in NHEK and NHDF, compared to NHEM, likely due to the UVR-protective effects of melanin in NHEM. Consistently, NHEK with phototype V (from darkly pigmented skin with higher melanin levels) exhibit significantly less UVA-induced DNA damage compared with phototype II NHEK. To create cellular models of dermal disease for DNA repair assays, we have successfully knocked out XPA in multiple NHDF cell lines with different phototypes using a CRISPR-Cas9 KO strategy, as confirmed by immunoblot and NGS sequence analyses. These and other engineered DNA repair-deficient skin cells will be assayed as single or mixed cell-type 2D cultures, with fluorescent labeling allowing for identification of subpopulations in comet and alkaline diffusion assays. This technology addresses the need for better platforms for rapid genotoxicity testing of safer and more effective chemical UV filters to prevent cutaneous carcinogenesis in diverse populations. Citation Format: Dean S. Rosenthal, Elijah Finn, Devin Teehan, Nusrat Islam, Veerupaxagouda Patil, Bonnie Carney, Scott S. Rosenthal, Lucia Dussan, Cynthia M. Simbulan-Rosenthal, Peter Sykora. Developing the UValidate platform to measure DNA damage and repair capacity in isogenic donor-derived skin keratinocytes, fibroblasts and melanocyte cell-lines with different Fitzpatrick phototypes [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: DNA Damage Repair: From Basic Science to Future Clinical Application; 2024 Jan 9-11; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2024;84(1 Suppl):Abstract nr B035.

Pharmacokinetics of Glutapyrone and its Impact on Expression of the Genes Involved in DNA Repair and Free Radical Production in Intact and Diabetic Rats

Abstract Modification of expression of several genes encoding enzymes involved in radical production and DNA repair by a 1,4-DHP derivative glutapyrone was studied in intact rats and animals with streptozotocin diabetes mellitus. Glutapyrone stimulated iNos mRNA production in both kidneys and blood. The effect was stronger in kidneys of diabetic animals, however in blood the expression was down-regulated. The compound increased the Parp 1 gene expression in kidneys of both intact and diabetic animals; in blood the effect was adverse. Expression of XDh gene was significantly increased by glutapyrone in kidneys of intact and diabetic animals. Administration of the compound to intact animals triggered significant increase of DNA damage in white blood cells assayed by comet assay; in diabetic animals no effect was produced. To explain discrepancies with the formerly described effects of glutapyrone on cultured cells, metabolism of the compound was studied. Glutapyrone is either oxidised or the residue of glutamic acid is removed, glutapyrone turns into AV-153, and the latter is metabolised to smaller compounds. Formation of AV-153, a DNA binder and genotoxic compound in high concentrations, can explain DNA damage in white blood cells and stimulation of DNA repair.

Detection of DNA Damage in Fish using Comet Assay

Heavy metals have an enduring presence, risky characteristics, and the propensity to accumulate in the environment. This is why heavy metal toxics are widely acknowledged as harmful environmental pollutants. Heavy metals damage both aquatic and terrestrial ecosystems, posing a major risk to the environment and human health. Four freshwater fish species namely Labeo rohita, Catla catla, Hypophthalmichthys molitrix, and Ctenopharyngodon idella were the focus of this investigation. This study investigated the potential genotoxic effects of lead (Pb), copper (Cu), and cadmium (Cd) on the above fish species through the application of comet assay test. The fish were exposed to these metals at four distinct concentrations (19%, 24%, 31%, and 50% of the LC50) over the course of 40 days. All four fish species were exposed to metals to varying degrees, according to the genetic damage index, cumulative tail length of comets, and the proportion of damaged cells. In contrast to Catla catla, Hypophthalmichthys molitrix had the highest prevalence of DNA damage. The current study suggests that the presence of these particular metals in Pakistan's aquatic ecosystems may have an adverse effect on the DNA of the country's fish species. Metals cause damage to DNA in fibroblast cells through distinct mechanisms when present in water, air, and soil. Comet assay test has a remarkable sensitivity that helps to identify extremely low amounts of DNA damage. Out of the four fish species, Ctenopharyngodon idella showed higher levels of damaged cells, a higher genetic damage index, and a cumulative comet tail length as compared to others. All four fish species experienced a significant increase in DNA damage, genetic damage index, and comet tail length at 50% concentration of metals LC50.

Assessing the Efficacy of Fenugreek Saponin Nanoparticles in Attenuating Nicotine-Induced Hepatotoxicity in Male Rats.

During smoking, nicotine, the most bountiful compound in cigarettes, is absorbed into the body by the lungs and quickly metabolized in the liver, causing three major adverse impacts such as toxic, neoplastic, and immunomodulatory effects. Saponins extracted from several plants are reported to exhibit various biological actions, such as anticancer effects. So, the potential protective effect of fenugreek saponin and nanofenugreek saponin against toxicity induced by nicotine in male rats was investigated in this study. Animals were exposed to nicotine (1.5 mg/kg/day) and/or treated with fenugreek saponin (25, 50, and 100 mg/kg/day) and nanofenugreek saponin (20, 40, and 80 mg/kg/day). Comet assays, histopathological examination, and analyses for the expression levels of glutamate aspartate transporter (GLAST) and glutamate transporter-1 (GLT-1) genes in liver tissues as well as the activity of glutathione peroxidase (GPx) and glutathione-S-transferase (GST) were conducted. The results revealed that nicotine treatment induced a significant increase in DNA damage, decrease in the expression levels of (GLAST) and (GLT-1) genes, and increase in histopathological alterations in liver tissues. Moreover, nicotine treatment induced a significant reduction in the activity of antioxidant enzymes GPx and GST. On the other hand, administration of fenugreek saponin or nanofenugreek saponin with nicotine significantly decreased the DNA damage, increased the expression levels of (GLAST) and (GLT-1) genes, and decreased histopathological alterations in liver tissues. Additionally, a significant increase in the activities of GPx and GST was observed. The results suggested that DNA damage and histological injuries induced by nicotine were decreased by the administration of fenugreek saponin or nanofenugreek saponin; thus, fenugreek saponin and nanofenugreek saponin can be used as ameliorative agents against nicotine toxicity.

Assessment of DNA Damage Induced by Velum® Prime in Human Lymphocytes

Aim: Fluopyram is a mitochondrial complex II inhibitor with low water solubility and a relatively long half-life in soil. So it may also be dangerous for humans. The effect of fluopyram on DNA damage was evaluated in human lymphocytes using the comet assay.&#x0D; Materials and Methods: Lymphocytes of eight volunteers were isolated using histopaque-1077. Fluopyram was administered at doses of 0.05, 0.25, and 1.00 mg/mL for 1, 2, and 4 h. The comet assay was applied, and photographs of the slides were taken under a fluorescence microscope. 50 cells per slide were analyzed using the OpenComet software. The obtained results were statistically evaluated using one-way ANOVA.&#x0D; Results: Fluopyram treatments at 1.00 mg/mL for 1 h and 0.05, 0.25, and 1.00 mg/mL for 2 and 4 h resulted in a statistically significant increase in DNA damage compared to the internal control groups (p

Evaluation of Genotoxic and Cytotoxic Effects of Gluten in Male Albino Mice

Gluten is a protein commonly found in daily diets in the form of wheat, barley, rye, and other grains. It serves as the structural component in flour, providing the binding qualities that maintain the shape and texture of food items. This study aimed to investigate the genotoxic and cytotoxic effects of gluten on bone marrow chromosomes and DNA of male albino mice. The animals were divided into four groups: a control group, a negative control group that received an oral dose of 0.02M glacial acetic acid, and two groups that were treated with gluten dissolved in 0.02M glacial acetic acid at doses of 1.5 g/kg and 3.0 g/kg body weight. The treated animals received oral doses with non-consecutively three times a week for a period of four weeks. The study evaluated chromosomal aberrations in the bone marrow, micronucleus test, and DNA damage using the comet assay. The results of the study showed that treatment with 1.5 and 3.0g/kg body weight of gluten induced chromosomal aberrations and damage in DNA content, with an increase in the severity of effects at a higher dose of gluten. The chromosomal aberrations seen included deletion, fragment, centromeric attenuation, centric fusion, ring formation, end to end association, chromosomal gap, beaded chromosomes, and polyploidy. The micronucleus test revealed toxicity in the bone marrow, as shown by appearance of micronuclei in polychromatic erythrocytes and a reduction in the ratio of polychromatic erythrocytes. The comet assay showed a significant increase of DNA damage in the tail length of the comet cells. This study concluded that the treatment with gluten has detrimental effects on the bone marrow chromosomes and DNA of mice, as demonstrated by the increased chromosomal aberrations, micronuclei, and DNA damage observed in the treated mice. So, the use of gluten should be within an acceptable and safe range.

In vivo protective efficacy of astaxanthin against ionizing radiation-induced DNA damage.

Astaxanthin, a carotenoid pigment, is believed to be effective in the repair of DNA damage. Our study evaluates the effect of astaxanthin on DNA damage in rats exposed to whole-body radiotherapy using the comet assay. Thirty-two male rats were randomly divided into four groups (control, ionizing radiation, astaxanthin, and radiation+astaxanthin). The radiation and radiation+astaxanthin groups were exposed to X-rays at a dose of 8 gray (0.62 gray/min). Astaxanthin was administered at 4 mg/kg by gavage for 7 days starting from irradiation. The %TailDNA parameter was chosen as an indicator of DNA damage and the results were compared using one-way ANOVA. %TailDNA was 3.24 ± 3.12 in the control group, 2.85 ± 2.73 in the astaxanthin group, 4.11 ± 7.90 in the radiation group, and 3.59 ± 4.05 in the radiation+astaxanthin group. There was a significant increase in DNA damage in the radiation group, compared with the control and astaxanthin groups (p < .001). DNA damage was reduced in the radiation+astaxanthin group compared with the radiation group (p < .05). Although this decrease did not reduce damage to the level of the control group, it was significant. The decrease in radiation-induced DNA damage by astaxanthin administration in our study supports the hypothesis that astaxanthin is a promising agent for against/reducing DNA damage.

Impact of mobile phone-specific electromagnetic fields on DNA damage caused by occupationally relevant exposures: results of ex vivo experiments with peripheral blood mononuclear cells from different demographic groups.

The aim of this study was to investigate if age and body mass of humans have an impact on the DNA-damaging properties of high-frequency mobile phone-specific electromagnetic fields (HF-EMF, 1950 MHz, universal mobile telecommunications system, UMTS signal) and if this form of radiation has an impact on the genotoxic effects of occupationally relevant exposures. Pooled peripheral blood mononuclear cells (PBMC) from three groups [young normal weight, young obese (YO), and older age normal weight individuals] were exposed to different doses of HF-EMF (0.25, 0.5, and 1.0 W/kg specific absorption rate-SAR) and simultaneously or sequentially to different chemicals which cause DNA damage (CrO3, NiCl2, benzo[a]pyrene diol epoxide-BPDE, and 4-nitroquinoline 1-oxide-4NQO) via different molecular mechanisms. We found no difference in regard to the background values in the three groups but a significant increase of DNA damage (81% without and 36% with serum) in cells from old participants after radiation with 1.0 W/kg SAR 16 h. In combined treatment experiments we found no impact of the UMTS signal on chemically induced DNA damage in the different groups in general. However, a moderate decrease of DNA damage was seen in simultaneous treatment experiments with BPDE and 1.0 W/kg SAR in the YO group (decline 18%). Taken together our findings indicate that HF-EMF cause DNA damage in PBMC from older subjects (69.1 years). Furthermore, they show that the radiation does not increase induction of DNA damage by occupationally relevant chemicals.

Genotoxicity from metronidazole detected in vitro, but not in vivo, in healthy dogs in a randomized clinical trial.

To determine whether metronidazole (MTZ), at recommended therapeutic dosages in dogs, induces peripheral blood cell (PMBC) genotoxicity, using the γ-H2AX assay as a sensitive measure of DNA breaks. The secondary aim was to assess dose-dependent genotoxicity in vitro in dog and cat PBMCs exposed to increasing MTZ concentrations. 12 healthy employee- and student-owned dogs and blood samples from 2 other healthy untreated dogs and 2 healthy untreated cats. Screened dogs were randomized to receive lower-dose MTZ (7.5 mg/kg, PO, q 12 h) or higher-dose MTZ (20 mg/kg, PO, q 12 h) for 7 days. Blood was drawn at baseline, after the 1 week of treatment, and after a 1-week washout, for DNA damage assessment and serum MTZ concentration measurements. For in vitro studies, PBMCs from untreated healthy dogs and cats were exposed to 0 to 500 μg/mL MTZ. No dogs showed a significant increase in DNA damage at these MTZ dosages for 1 week. The highest serum MTZ concentration observed 1 hour after dosing was 36 μg/mL. In vitro, MTZ led to a significant increase in DNA damage at 100 μg/mL in both canine and feline PBMCs. Although MTZ was not significantly genotoxic in vivo in the healthy dogs in this study, MTZ was significantly genotoxic to canine PBMCs in vitro at 3-fold higher concentrations than those documented in vivo. The safety of MTZ in clinically ill dogs, which may have impaired MTZ clearance or DNA repair, should be assessed next.

Is a non-cytotoxic and non-genotoxic novel bioinspired dipeptide structure synthesis possible for theragnostic applications?

The diagnosis and treatment of the diseases in a certain coordination is a subject that has been emphasized in recent years. Theragnostics approaches allow simultaneous diagnosis and treatment of chronic diseases such as cancer. An ideal theragnostic should be biocompatible and can be used safely in humans. Although several types of theragnostics have been developed, none of yet satisfied these criteria. Bioinspired materials with noble metal centers encapsulating therapeutic and imaging agents were shown to possess theragnostic activities. In this study, it was aimed to synthesize, characterize, and evaluate the cytotoxic and genotoxic effects of self-assembly of diphenylalanine (Phe–Phe) dipeptides presence of mercury (Hg2+) ions to be used for theragnostic. Cytotoxicity and genotoxicity studies were done in mouse fibroblast (NIH/3T3) cells by 3-(4,5-Dimethylthiazol-2-yl)- 2,5-diphenyltetrazolium bromide (MTT) and single cell gel electrophoresis (Comet) assays, respectively. It was found that cell viability decreased in a dose-dependent manner in 24-, 48-, and 72-h treatment. Also, Phe–Phe dipeptides did not cause any significant changes in DNA damage at the concentrations of 1, 2, and 5 mg/mL in 4- and 24-h exposures. In the 48-h exposure, Phe–Phe peptide exposure at concentrations of 2 and 5 mg/mL caused a significant increase in DNA damage and in the 72-h of exposure, a significant increase in DNA damage was observed at all studied concentrations. According to the results of the study, it can be said that Phe–Phe dipeptides presence of Hg2+ ions are biocompatible and can be used safely for theragnostic purposes.

Does age pay off? Effects of three-generational experiments of nanodiamond exposure and withdrawal in wild and longevity-selected model animals.

Nanodiamonds (NDs) are considered a material with low toxicity. However, no studies describe the effects of ND withdrawal after multigenerational exposure. The aim was to evaluate ND exposure (in the 1st and 2nd generations) effects at low concentrations (0.2 or 2mgkg-1) and withdrawal (in the 3rd generation) in the wild (H) and longevity-selected (D) model insect Acheta domesticus. We measured selected oxidative stress parameters, immunity, types of cell death, and DNA damage. Most of the results obtained in the 1st generation, e.g., catalase (CAT), total antioxidant capacity (TAC), heat shock proteins (HSP70), defensins, or apoptosis level, confirmed no significant toxicity of low doses of NDs. Interestingly, strain-specific differences were observed. D-strain crickets reduced autophagy, the number of ROS+cells, and DNA damage. The effect can be a symptom of mobilization of the organism and stimulation of physiological defense mechanisms in long-living organisms. The 2nd-generation D-strain insects fed ND-spiked food at higher concentrations manifested a reduction in CAT, TAC, early apoptosis, and DNA damage, together with an increase in HSP70 and defensins. ROS+cells and cells with reduced membrane potential and autophagy did not differ significantly from the control. H-strain insects revealed a higher number of ROS+cells and cells with reduced membrane potential, decreased CAT activity, and early apoptosis. Elimination of NDs from the diet in the 3rd generation did not cause full recovery of the measured parameters. We noticed an increase in the concentration of HSP70 and defensins (H-strain) and a decrease in apoptosis (D-strain). However, the most visible increase was a significant increase in DNA damage, especially in H-strain individuals. The results suggest prolonged adverse effects of NDs on cellular functions, reaching beyond "contact time" with these particles. Unintentional and/or uncontrolled ND pollution of the environment poses a new challenge for all organisms inhabiting it, particularly during multigenerational exposure.

Impact of AKT1 polymorphism on DNA damage, BTG2 expression, and risk of colorectal cancer development.

BackgroundAKT, also called protein kinase B, is a serine-threonine kinase that functions as a mediator of PI3K-Akt-mTOR signaling pathway and plays an important role in an array of cellular processes. Many single nucleotide polymorphisms (SNP) in AKT gene have been observed to be associated with various types of cancers. In the current research the association of a functional SNP rs1130233 in AKT, depicting G to A transition, was studied with AKT activation, DNA damage, an early response B-cell translocation gene 2 (Btg2) expression and risk of colorectal cancer (CRC) development.Patients and methodsA total 197 population-based controls and 200 CRC patients were genotyped for SNP rs1130233. AKT expression, activation and BTG2 expression were determined in GG, AG and AA genotype carriers. DNA damage was determined through comet assay.ResultsThe heterozygous AG genotype (55.67%) was more prevalent in the local population compared to homozygous wild type GG (37.78%) and homozygous AA genotypes (6.55%). Moreover, AG and AA alleles were observed to be significant contributors (P = 0.01, OR = 1.80, CI = 1.18 to 2.74, and P = 0.001, OR = 5.00, CI = 1.90 to 13.18, respectively) in increasing the risk of CRC. The immunoblot analysis revealed that G to A transition decreased the expression and activation of AKT. Moreover, AG and AA genotypes of AKT1 rs1130233 showed a significant increase in DNA damage and Btg2 expression.ConclusionsThe data concludes that G to A substitution is a risk factor for CRC development involving a decrease in AKT expression and activation and increase in DNA damage.

Protective effect of green synthesized Selenium Nanoparticles against Doxorubicin induced multiple adverse effects in Swiss albino mice

AimsDoxorubicin (DOX) is a widely used drug against multiple cancers. However, its clinical Use is often restricted due to multiple adverse effects. Recently, Selenium Nanoparticles (SeNPs) are gaining attention due to their low toxicity and higher biocompatibility, making them attractive nanoparticles (NPs) in medical and pharmaceutical sciences. Therefore, the current study aimed to assess if our biosynthesized SeNP from the endophytic fungus Fusarium oxysporum conjugated with DOX could alleviate the DOX-induced adverse effects. Main methodsFor this purpose, we investigated various genotoxic, biochemical, histopathological, and immunohistochemical parameters and finally analyzed the metabolite profile by LC-MS/MS. Key findingsWe observed that DOX causes an increase in reactive oxygen and nitrogen species (ROS, RNS), 8-OHdG, and malondialdehyde (MDA), decreases antioxidant defense systems and reduces BCL-2 expression in cardiac tissue. In addition, a significant increase in DNA damage and alteration in the cytoarchitecture of the liver, kidney, and heart tissues was observed by Comet Tail Length and histopathological studies, respectively. Interestingly, the DOX-SeNP conjugate reduced ROS/RNS, 8-OHdG, and MDA levels in the liver, kidney, and heart tissues. It also restored the antioxidant enzymes and cytoarchitectures of the examined tissues, reduced genotoxicity, and increased the BCL-2 levels. Finally, metabolic profiling showed that DOX reduced the number of cardioprotective metabolites, which DOX-SeNP restored. SignificanceCollectively, the present results describe the protective effect of DOX-conjugated SeNP against DOX-induced toxicities. In conclusion, DOX-SeNP conjugate might be better for treating patients receiving DOX alone. However, it warrants further thorough investigation.

Evaluation of DNA Damage of Cadmium in Gastropod Lymnaea radix cor (Annandale and Prashad, 1919) From Euphrates River

Cadmium toxicity to a snail Lymnaea radix cor collected from Shatt Almadina stream that belongs to Euphrates River, Basra province, Iraq was investigated. DNA damage was used as an indicator for cadmium toxicity in the current study. The adult snails were exposed to several concentrations of cadmium for different periods. DNA fragmentation occurring in the snail exposed to cadmium was substantiated by comet assay and expressed in term Tail DNA percentage. Results revealed a significant increase in DNA damage at cadmium concentrations 60, 80, and 100µg/l for an exposure time of 3 days, and the highest percentage of tail DNA was at the cadmium concentration of 100µg/l. On the other hand, the DNA damage significantly elevated when the exposure period increased to 5 days and the highest tail DNA percentage (18%) was recorded at cadmium concentration 100 µg/l. the assessment of DNA damage in the freshwater snail Lymnaea radix cor gives an early caution signal for aquatic environmental contamination by cadmium.

Genotoxicity test of eight natural color additives in the Korean market.

BackgroundVarious natural color additives are preferred by many consumers over synthetic color additives because they are perceived to be safer. However, most do not have sufficient toxicity data for safety assurance. Color ingredients in particular have some structures suspected of being toxic. Eight natural color additives, gardenia red, blue, and yellow; lac color; cochineal extract; beet red; Curcuma longa Linne extract (Curcuma extract); and Monascus red, currently permitted for use in Korea, were selected and subjected to genotoxicity tests. Acceptable daily intake values have not been allocated to these color additives (except for cochineal extract) due to the lack of toxicity data. We used genotoxicity testing—the bacterial reverse mutation test (Ames test), in vitro mammalian chromosomal aberration test, and in vivo alkaline comet test—for minimum safety assurance.ResultsGardenia red and blue, cochineal extract, lac color, and beet red did not induce mutagenicity or chromosomal abnormalities. Gardenia yellow was mutagenic in the Ames test, but was not positive in the in vitro chromosomal aberration test or in vivo alkaline comet assay. Curcuma extract and Monascus red induced cytotoxicity in the Ames test at high concentrations in Salmonella typhimurium TA1537 and TA100, without showing mutagenicity. On cytotoxicity testing, Curcuma extract and Monascus red showed cytotoxicity at concentrations higher than 313 μg/ml in Chinese hamster ovary CHO-K1 cells and showed equivocal results in chromosomal aberration assay of the same cells. Curcuma extract and Monascus red produced significant increases in DNA damage at a dose of 2000 mg/kg b.w./day, and induced dose-dependent increases in % DNA in the tail and tail moment on in vivo comet assay.ConclusionsSix out of eight food colorants did not cause genotoxicity and cytotoxicity. However, Monascus red and Curcuma extract showed definite cytotoxicity and probable genotoxicity.

Evaluation of gamma radiation–induced genotoxicity in the workers of Italian honey bees, Apis mellifera ligustica, using single cell gel electrophoresis (comet) assay

The environment exposed to radionuclide faces detrimental effects of ionizing radiations and these radiations can damage DNA by inducing genotoxicity in living organisms. The gamma radiation induced genotoxicity was evaluated by employing Single cell gel electrophoresis (comet) assay in the foragers of Apis mellifera ligustica by exposing to different doses (1 to 60 Gy) of gamma radiation. DNA damage was measured as the percentage of comet tail DNA. The results showed a dose dependent increase and post irradiation time (1-24 h) dependent decrease in % tail DNA level in bee foragers. A significant increase in DNA damage was observed in all the samples and the extent of damage was proportional to the dose of gamma radiation received by the bees except in those treated with the lower doses (1, 5 and 10 Gy) of gamma radiation. The highest amount of DNA damage was recorded at 1 h post-irradiation which decreased gradually with time, that is, at 3 h and 6 h post-irradiation. However, there were no significant differences in the % tail DNA of bees of 12 h and 24 h post irradiation. The present study shows gamma radiation induced DNA damage in foragers of A. m. ligustica and also the comet assay is a suitable technique for detection of gamma radiation induced DNA damage.