Levels Of Oxidative DNA Damage Research Articles

GSTT1/GSTM1 deficiency aggravated cisplatin-induced acute kidney injury via ROS-triggered ferroptosis.

Cisplatin is a widely used chemotherapeutic agent prescribed to treat solid tumors. However, its clinical application is limited because of cisplatin- induced nephrotoxicity. A known complication of cisplatin is acute kidney injury (AKI). Deletion polymorphisms of GSTM1 and GSTT1, members of the glutathione S-transferase family, are common in humans and are presumed to be associated with various kidney diseases. However, the specific roles and mechanisms of GSTM1 and GSTT1 in cisplatin induced AKI remain unclear. To investigate the roles of GSTM1 and GSTT1 in cisplatin-induced AKI, we generated GSTM1 and GSTT1 knockout mice using CRISPR-Cas9 technology and assessed their kidney function under normal physiological conditions and cisplatin treatment. Using ELISA kits, we measured the levels of oxidative DNA and protein damage, along with MDA, SOD, GSH, and the GSH/GSSG ratio in wild-type and GSTM1/GSTT1 knockout mice following cisplatin treatment. Additionally, oxidative stress levels and the expression of ferroptosis-related proteins in kidney tissues were examined through Western blotting, qPCR, immunohistochemistry, and immunofluorescence techniques. Here, we found that GSTT1 and GSTM1 were downregulated in the renal tubular cells of AKI patients and cisplatin-treated mice. Compared with WT mice, Gstm1/Gstt1-DKO mice were phenotypically normal but developed more severe kidney dysfunction and exhibited increased ROS levels and severe ferroptosis after injecting cisplatin. Our study revealed that GSTM1 and GSTT1 can protect renal tubular cells against cisplatin-induced nephrotoxicity and ferroptosis, and genetic screening for GSTM1 and GSTT1 polymorphisms can help determine a standard cisplatin dose for cancer patients undergoing chemotherapy.

The protective effects of chitosan and curcumin nanoparticles against the hydroxyapatite nanoparticles-induced neurotoxicity in rats

Hydroxyapatite nanoparticles (HANPs) have extensive applications in biomedicine and tissue engineering. However, little information is known about their toxicity. Here, we aim to investigate the possible neurotoxicity of HANPs and the possible protective role of chitosan nanoparticles (CNPs) and curcumin nanoparticles (CUNPs) against this toxicity. In our study, HANPs significantly reduced the levels of neurotransmitters, including acetylcholine (Ach), dopamine (DA), serotonin (SER), epinephrine (EPI), and norepinephrine (NOR). HANPs significantly suppressed cortical expression of the genes controlling mitochondrial biogenesis such as peroxisome proliferator activator receptor gamma coactivator 1α (PGC-1α) and mitochondrial transcription factor A (mTFA). Our findings revealed significant neuroinflammation associated with elevated apoptosis, lipid peroxidation, oxidative DNA damage and nitric oxide levels with significant decline in the antioxidant enzymes activities and glutathione (GSH) levels in HANPs-exposed rats. Meanwhile, co-supplementation of HANP-rats with CNPs and/or CUNPs significantly showed improvement in levels of neurotransmitters, mitochondrial biogenesis, oxidative stress, DNA damage, and neuroinflammation. The co-supplementation with both CNPs and CUNPs was more effective to ameliorate HANPs-induced neurotoxicity than each one alone. So, CNPs and CUNPs could be promising protective agents for prevention of HANPs-induced neurotoxicity.

8-OxodG: A Potential Biomarker for Chronic Oxidative Stress Induced by High-LET Radiation.

Oxidative stress-mediated biomolecular damage is a characteristic feature of ionizing radiation (IR) injury, leading to genomic instability and chronic health implications. Specifically, a dose- and linear energy transfer (LET)-dependent persistent increase in oxidative DNA damage has been reported in many tissues and biofluids months after IR exposure. Contrary to low-LET photon radiation, high-LET IR exposure is known to cause significantly higher accumulations of DNA damage, even at sublethal doses, compared to low-LET IR. High-LET IR is prevalent in the deep space environment (i.e., beyond Earth's magnetosphere), and its exposure could potentially impair astronauts' health. Therefore, the development of biomarkers to assess and monitor the levels of oxidative DNA damage can aid in the early detection of health risks and would also allow timely intervention. Among the recognized biomarkers of oxidative DNA damage, 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-OxodG) has emerged as a promising candidate, indicative of chronic oxidative stress. It has been reported to exhibit differing levels following equivalent doses of low- and high-LET IR. This review discusses 8-OxodG as a potential biomarker of high-LET radiation-induced chronic stress, with special emphasis on its potential sources, formation, repair mechanisms, and detection methods. Furthermore, this review addresses the pathobiological implications of high-LET IR exposure and its association with 8-OxodG. Understanding the association between high-LET IR exposure-induced chronic oxidative stress, systemic levels of 8-OxodG, and their potential health risks can provide a framework for developing a comprehensive health monitoring biomarker system to safeguard the well-being of astronauts during space missions and optimize long-term health outcomes.

Identification of Penexanthone A as a Novel Chemosensitizer to Induce Ferroptosis by Targeting Nrf2 in Human Colorectal Cancer Cells.

Ferroptosis has emerged as a potential mechanism for enhancing the efficacy of chemotherapy in cancer treatment. By suppressing nuclear factor erythroid 2-related factor 2 (Nrf2), cancer cells may lose their ability to counteract the oxidative stress induced by chemotherapy, thereby becoming more susceptible to ferroptosis. In this study, we investigate the potential of penexanthone A (PXA), a xanthone dimer component derived from the endophytic fungus Diaporthe goulteri, obtained from mangrove plant Acanthus ilicifolius, to enhance the therapeutic effect of cisplatin (CDDP) on colorectal cancer (CRC) by inhibiting Nrf2. The present study reported that PXA significantly improved the ability of CDDP to inhibit the activity of and induce apoptosis in CRC cells. Moreover, PXA was found to increase the level of oxidative stress and DNA damage caused by CDDP. In addition, the overexpression of Nrf2 reversed the DNA damage and ferroptosis induced by the combination of PXA and CDDP. In vivo experiments using zebrafish xenograft models demonstrated that PXA enhanced the therapeutic effect of CDDP on CRC. These studies suggest that PXA enhanced the sensitivity of CRC to CDDP and induce ferroptosis by targeting Nrf2 inhibition, indicating that PXA might serve as a novel anticancer drug in combination chemotherapy.

The interplay of DNA damage and repair, gene expression, and mutagenesis in mammalian cells during oxidative stress.

We investigated the interplay among oxidative DNA damage and repair, expression of genes encoding major base excision repair (BER) enzymes and bypass DNA polymerases, and mutagenesis in mammalian cells. Primary mouse embryonic fibroblasts were challenged with oxidative stress induced by methylene blue plus visible light, and formation and repair of DNA damage, changes in gene expression, and mutagenesis were determined at increasing intervals post-treatment (0 - 192 hours). Significant formation of oxidative DNA damage together with upregulation of Ogg1, Polβ, and Polκ, and no changes in Mutyh and Nudt1 expression were found in treated cells. There was a distinct interconnection between Ogg1 and Polβ expression and DNA damage formation and repair whereby changes in expression of these two genes were proportionate to the levels of oxidative DNA damage, once a 3-plus hour lag time passed (P < 0.05). Equally notable was the matching pattern of Polκ expression and kinetics of oxidative DNA damage and repair (P < 0.05). The DNA damage and gene expression data were remarkably consistent with mutagenicity data in the treated cells; the induced mutation spectrum is indicative of erroneous bypass of oxidized DNA bases and incorporation of oxidized deoxynucleoside triphosphates during replication of the genomic DNA. Our findings support follow-up functional studies to elucidate how oxidation of DNA bases and the nucleotide pool, overexpression of Polκ, delayed upregulation of Ogg1 and Polβ, and inadequate expression of Nudt1 and Mutyh collectively affect mutagenesis consequent to oxidative stress.

IL-17A Drives Oxidative Stress and Cell Growth in A549 Lung Epithelial Cells: Potential Protective Action of Oleuropein.

IL-17A drives inflammation and oxidative stress, affecting the progression of chronic lung diseases (asthma, chronic obstructive pulmonary disease (COPD), lung cancer, and cystic fibrosis). Oleuropein (OLP) is a polyphenolic compound present in olive oil and widely included in the Mediterranean diet. It exerts antioxidant and anti-inflammatory activities, oxidative stress resistance, and anticarcinogenic effects with a conceivable positive impact on human health. We hypothesized that OLP positively affects the mechanisms of oxidative stress, apoptosis, DNA damage, cell viability during proliferation, and cell growth in alveolar epithelial cells and tested its effect in a human alveolar epithelial cell line (A549) in the presence of IL-17A. Our results show that OLP decreases the levels of oxidative stress (Reactive Oxygen Species, Mitochondrial membrane potential) and DNA damage (H2AX phosphorylation-ser139, Olive Tail Moment data) and increases cell apoptosis in A549 cells exposed to IL-17A. Furthermore, OLP decreases the number of viable cells during proliferation, the migratory potential (Scratch test), and the single cell capacity to grow within colonies as a cancer phenotype in A549 cells exposed to IL-17A. In conclusion, we suggest that OLP might be useful to protect lung epithelial cells from oxidative stress, DNA damage, cell growth, and cell apoptosis. This effect might be exerted in lung diseases by the downregulation of IL-17A activities. Our results suggest a positive effect of the components of olive oil on human lung health.

Dapagliflozin suppresses diabetes-induced oxidative DNA damage and hypermethylation in mouse somatic cells

Diabetes mellitus is a complex metabolic disorder resulting from the interplay of environmental, genetic, and epigenetic factors that increase the risk of cancer development. However, it is unclear whether the increased cancer risk is due to poor glycemic control or the use of some antidiabetic medications. Therefore, we investigated the genetic and epigenetic changes in somatic cells in a mouse model of diabetes and studied whether multiple exposures to the antidiabetic medication dapagliflozin influence these changes. We also elucidated the mechanism(s) of these ameliorations. The micronucleus test and modified comet assay were used to investigate bone marrow DNA damage and methylation changes. These assays revealed that dapagliflozin is non-genotoxic in the tested regimen, and oxidative DNA damage and hypermethylation were significantly higher in diabetic mice. Spectrophotometry also evaluated oxidative DNA damage and global DNA methylation, revealing similar significant alterations induced by diabetes. Conversely, the dapagliflozin-treated diabetic animals significantly reduced these changes. The expression of some genes involved in DNA repair and DNA methylation was disrupted considerably in the somatic cells of diabetic animals. In contrast, dapagliflozin treatment significantly restored these disruptions and enhanced DNA repair. The simultaneous effects of decreased oxidative DNA damage and hypermethylation levels suggest that dapagliflozin can be used as a safe antidiabetic drug to reduce DNA damage and hypermethylation in diabetes, demonstrating its usefulness in patients with diabetes to control hyperglycemia and decrease the development of its subsequent complications.

Are bioplastics safe? Hazardous effects of polylactic acid (PLA) nanoplastics in Drosophila

The expanded uses of bioplastics require understanding the potential health risks associated with their exposure. To address this issue, Drosophila melanogaster as a versatile terrestrial in vivo model was employed, and polylactic acid nanoplastics (PLA-NPLs), as a proxy for bioplastics, were tested as a material model. Effects were determined in larvae exposed for 4 days to different concentrations (25, 100, and 400 μg/mL) of 463.9 ± 129.4 nm PLA-NPLs. Transmission electron microscopy (TEM) and scanning electron microscope (SEM) approaches permitted the detection of PLA-NPLs in the midgut lumen of Drosophila larvae, interacting with symbiotic bacteria. Enzymatic vacuoles were observed as carriers, collecting PLA-NPLs and enabling the crossing of the peritrophic membrane, finally internalizing into enterocytes. Although no toxic effects were observed in egg-to-adult survival, cell uptake of PLA-NPLs causes cytological disturbances and the formation of large vacuoles. The translocation across the intestinal barrier was demonstrated by their presence in the hemolymph. PLA-NPL exposure triggered intestinal damage, oxidative stress, DNA damage, and inflammation responses, as evaluated via a wide set of marker genes. Collectively, these structural and molecular interferences caused by PLA-NPLs generated high levels of oxidative stress and DNA damage in the hemocytes of Drosophila larvae. The observed effects point out the need for further studies aiming to deepen the health risks of bioplastics before adopting their uses as a safe plastic alternative.

Oxidation of DNA and RNA in young patients with newly diagnosed bipolar disorder and relatives

Excessive oxidative stress-generated nucleoside damage seems to play a key role in bipolar disorder (BD) and may present a trait phenomenon associated with familial risk and is one of the putative mechanisms explaining accelerated atherosclerosis and premature cardiovascular diseases (CVD) in younger patients with BD. However, oxidative stress-generated nucleoside damage has not been studied in young BD patients and their unaffected relatives (UR). Therefore, we compared oxidative stress-generated damage to DNA and RNA in young patients newly diagnosed with BD, UR, and healthy control individuals (HC). Systemic oxidative stress-generated DNA and RNA damage levels were compared by analyzing urinary levels of 8-oxo-7,8-dihydro-2′-deoxyguanosine and 8-oxo-7,8-dihydroguanosine in participants aged 15–25 years, including 133 patients newly diagnosed with BD, 57 UR, and 83 HC. Compared with HC, damage to DNA was 21.8% higher in BD patients (B = 1.218, 95% CI = 1.111–1.335, p = <0.001) and 22.5% higher in UR (B = 1.225, 95% CI = 1.090–1.377, p = <0.002), while damage to RNA was 14.8% higher in BD patients (B = 1.148, 95% CI = 1.082–1.219, p = <0.001) and 14.0% higher in UR (B = 1.140, 95% CI = 1.055–1.230, p = < 0.001) in models adjusted for sex and age after correction for multiple comparison. Levels did not differ between patients with BD and UR. Our findings support higher oxidative stress-generated nucleoside damage being a trait phenomenon in BD associated with familial risk and highlight the importance of early diagnosis and treatment to prevent illness progression and development of premature CVD.

Dose-dependent exposure to indoxyl sulfate alters AHR signaling, sirtuins gene expression, oxidative DNA damage, and bone mineral status in rats

Indoxyl sulfate (IS), an agonist of aryl hydrocarbon receptors (AhR), can accumulate in patients with chronic kidney disease, but its direct effect on bone is not clear. The present study investigated the effect of chronic exposure to low (100 mg/kg b.w.; 100 IS) and high (200 mg/kg b.w.; 200 IS) dose of IS on bone AhR pathway, sirtuins (SIRTs) expression, oxidative DNA damage and bone mineral status in Wistar rats. The accumulation of IS was observed only in trabecular bone tissue in both doses. The differences were observed in the bone parameters, depending on the applied IS dose. The exposure to 100 IS increased AhR repressor (AhRR)-CYP1A2 gene expression, which was associated with SIRT-1, SIRT-3 and SIRT-7 expression. At the low dose group, the oxidative DNA damage marker was unchanged in the bone samples, and it was inversely related to the abovementioned SIRTs expression. In contrast, the exposure to 200 IS reduced the expression of AhRR, CYP1A, SIRT-3 and SIRT-7 genes compared to 100 IS. The level of oxidative DNA damage was higher in trabecular bone in 200 IS group. Femoral bone mineral density was decreased, and inverse relations were noticed between the level of trabecular oxidative DNA damage and parameters of bone mineral status. In conclusion, IS modulates AhR-depending signaling affecting SIRTs expression, oxidative DNA damage and bone mineral status in a dose dependent manner.

Genoprotective role of pembrolizumab liposome in isolated lymphocytes from head and neck squamous cell carcinoma patients compared to those from healthy individuals in vitro

Pembrolizumab has shown significant anticancer effects against various human cancers. The present study investigated the effects of pembrolizumab liposome and nano (naked) forms in treated lymphocytes from head and neck squamous cell carcinoma (HNSCC) patients compared to healthy individuals. The level of oxidative DNA damage induced by hydrogen peroxide (H2O2) was also investigated. A concentration of 10 µg/ml of pembrolizumab liposome was used to treat the lymphocytes in the Comet and micronucleus assays based on the preliminary dosage optimization tests. To determine the cellular pathways involved in the protective role of pembrolizumab against H2O2, several proteins involved in apoptosis (P53, P21 and Bcl-2) were assessed. Pembrolizumab significantly reduced DNA damage and decreased the number of micronuclei in lymphocytes from HNSCC patients (p < 0.01) compared with healthy individuals. The 10 µg/ml of pembrolizumab liposome significantly reduced the oxidative stress induced by H2O2 and was effective in healthy and HNSCC groups using the Comet and micronucleus assays (p < 0.001). To our knowledge, this is the first report of pembrolizumab in liposome and naked forms exhibiting a protective effect on DNA damage in the treatment of HNSCC patients.

Aqueous Extract Analysis of Lens Epithelial Cells: Unraveling the Link between Oxidative DNA Damage and Malondialdehyde in Senile Cataract

Background and Aims: The purpose of this study was to examine the level of oxidative stress in people with cataracts, based on previous studies that indicated its role in causing DNA damage and cataract formation. The study also sought to determine the correlation between the degree of DNA damage and the concentration of malondialdehyde, a marker of lipid peroxidation, in patients with senile cataracts. Methods: The study involved 30 senile cataract patients aged 50-80 years and 12 cadaveric donors of corneal tissue who died in road accidents. They were selected from the ophthalmology ward of Acharya Vinoba Bhave Hospital. The aim was to measure DNA damage in human lens epithelial cells (HLECs) by Comet assay and malondialdehyde levels in the aqueous extract of HLECs. Results: The study found that the oxidative DNA damage level of human lens epithelial cells is not correlated with the malondialdehyde levels in the aqueous extract of HLECs in senile cataract patients. Conclusions: The study did not support the hypothesis that oxidative stress is a major factor in the development of cataracts. The results suggest that other mechanisms, such as genetic factors, environmental factors may be more relevant in the pathogenesis of cataracts.

Piperlongumine mediates amelioration of osteoarthritis via inhibition of chondrocyte senescence and inflammation in a goat ex vivo model

In osteoarthritis (OA), chondrocytes manifest senescence, which results in a vicious signaling loop that aids the progression of the disease. More specifically, inflammation-associated senescence is one of the major regulators of the initiation and progression of OA. Therefore, we targeted senescence through inflammation with a pharmacological approach for OA amelioration. In this study, we first confirmed the suitability of the IL1β-induced goat ex vivo OA model (emphasizing 3R's principle) for the screening of senotherapeutics, namely, ABT-263, ABT-737, and Piperlongumine (PL), wherein PL showed a positive outcome in the preliminary studies. Thereafter, we determined the cytocompatible concentrations of PL using live/dead staining. Further, treatment of ex vivo OA cartilage with PL exhibited a concentration-dependent increase in the retention of key cartilage matrix components. We then examined the effect of PL on chondrocyte senescence and observed a decreased expression of major senescence markers in the PL-treated groups. Interestingly, PL treatment reduced the expression of major downstream effectors of the chondrocyte senescence pathway in a concentration-dependent manner at both gene and protein levels. Moreover, IL1β-induced elevated levels of oxidative stress and DNA damage in cartilage explants were rescued by all the tested concentrations of PL. In addition, PL also reduced the expression of major inflammatory markers of OA in the goat ex vivo OA model. Finally, we proposed a model for the mechanism of action of PL in the treatment of OA. Overall, PL showed a promising outcome as a senotherapeutic for the amelioration of OA in the goat ex vivo OA model.

Differential Modulation of Markers of Oxidative Stress and DNA Damage in Arterial Hypertension.

Patients with arterial hypertension have an increased risk of developing tumors, particularly renal cell carcinoma. Arterial hypertension is linked to DNA damage via the generation of oxidative stress, in which an upregulated renin-angiotensin-aldosterone system plays a crucial role. The current study investigated surrogates of oxidative stress and DNA damage in a group of hypertensive patients (HypAll, n = 64) and subgroups of well (HypWell, n = 36) and poorly (HypPoor, n = 28) controlled hypertensive patients compared to healthy controls (n = 8). In addition, a longitudinal analysis was performed with some of the hypertensive patients. Markers for oxidative stress in plasma (SHp, D-ROM, and 3-nitrotyrosine) and urine (8-oxodG, 15-F2t-isoprostane, and malondialdehyde) and markers for DNA damage in lymphocytes (γ-H2AX and micronuclei) were measured. In HypAll, all markers of oxidative stress except malondialdehyde were increased compared to the controls. After adjustment for age, this association was maintained for the protein stress markers SHp and 3-nitrotyrosine. With regard to the markers for DNA damage, there was no difference between HypAll and the controls. Further, no significant differences became apparent in the levels of both oxidative stress and DNA damage between HypWell and HypPoor. Finally, a positive correlation between the development of blood pressure and oxidative stress was observed in the longitudinal study based on the changes in D-ROM and systolic blood pressure. In conclusion, we found increased oxidative stress in extensively treated hypertensive patients correlating with the level of blood-pressure control but no association with DNA damage.

Effect of Barley Grass on Antioxidant Capacity and DNA Damage in Diabetic Rats

Objective: Worldwide, phytotherapy methods acquire great importance, and studies in this field are increasing their importance each day. This study, it was aimed to examine total antioxidant, oxidant status, oxidative DNA damage, glucose and hemoglobin A1c levels and the effects of barley grass juice on these parameters in rats with diabetes mellitus.&#x0D; Material and Method: Four groups were formed for the study and 6 male rats weighing 250-350 g were used in each group. Control Group; physiological saline was injected via intraperitoneal., Diabetic Group; created using streptozotocin, Barley Grass Group; Barley grass juice (3 ml/rat/day) was given orally for 4 weeks, Diabetic and Barley Grass Group; was injected streptozotocin and barley grass juice was given by oral for 4 weeks.&#x0D; Results: It was determined that barley grass juice decreased blood sugar, glucose, hemoglobin A1c, total oxidative status and oxidative stress index values, increased total anti-oxidative status value, and body weights in streptozotocin-induced diabetes. In addition, it was determined that the addition of barley grass juice provided a significant protective effect and improvement in these parameters.&#x0D; Conclusion: Based on these findings, we can say that barley grass juice has an antidiabetic-antioxidant effect and weight gain in diabetes mellitus

High urinary oxidative DNA damage in wild chimpanzees ranging in proximity of agricultural fields in Sebitoli area, Uganda.

Agriculture expansion is a major cause of habitat loss and exposure to phytochemical pollution for non-human primates. In addition to endocrine disruption, exposure to pesticides may have other sublethal physiological consequences for animals, such as generation of oxidative damage to macromolecules. In this study, we analyzed the pesticides contained in the river water across the home range of wild chimpanzees (Pan troglodytes) in Sebitoli area located on the Northern part of Kibale National Park (Uganda). We tested whether levels of three urinary markers of oxidative damage vary among individuals in relation to their ranging patterns, as a proxy for pesticide exposure intensity. To better characterize the foraging habitat use, the trophic level, and the energetic status of study individuals, we also quantified urinary levels of carbon and nitrogen stable isotope signatures and of C-peptide. Among the 511 pesticides screened, 18 compounds including herbicides, insecticides, and fungicides were found in the water sampled in the Western part of the home range of chimpanzees. In this area, chimpanzees used to feed on maize crops. By contrast, in the Eastern part where crop feeding was never observed, we found only seven pesticides. According to their ranging patterns and thus crop feeding frequency, the 139 urine samples collected from 43 Sebitoli chimpanzees were categorized as belonging to low, medium, and high exposure level. Chimpanzees from the high exposure zone had higher oxidative DNA damage (8-OHdG) than chimpanzees from both the low and medium exposure groups, who had similar levels of oxidative DNA damage. In addition, individuals with higher C-peptide tended to have significantly higher oxidative DNA damage and lipid peroxides. The three exposure groups had similar levels of urinary 8-isoprostanes and of urinary lipid peroxides. These results were robust for any potential confounding effect of other variables because neither age category nor sex or isotope levels were significantly associated with markers of oxidative damage. Our study points to genotoxic effects as one potential sublethal consequence of ranging in proximity of agricultural fields owing to exposure to pesticides or other unidentified sources of stress. Given our phylogenetic proximity, this information is relevant for the conservation of this species which is endangered and also sentinel for human health.

Development of a model for studying the developmental consequences of oxidative sperm DNA damage by targeting redox-cycling naphthoquinones to the Sertoli cell population.

Oxidative stress can be induced in the testes by a wide range of factors, including scrotal hyperthermia, varicocele, environmental toxicants, obesity and infection. The clinical consequences of such stress include the induction of genetic damage in the male germ line which may, in turn, have serious implications for the health and wellbeing of the progeny. In order to confirm the transgenerational impact of oxidative stress in the testes, we sought to develop an animal model in which this process could be analysed. Our primary approach to this problem was to induce Sertoli cells (robust, terminally differentiated, tissue-specific testicular cells whose radioresistance indicates significant resistance to oxidative stress) to generate high levels of reactive oxygen species (ROS) within the testes. To achieve this aim, six follicle-stimulating hormone (FSH) peptides were developed and compared for selective targeting to Sertoli cells both in vitro and in vivo. Menadione, a redox-cycling agent, was then conjugated to the most promising FSH candidate using a linker that had been optimised to enable maximum production of ROS in the targeted cells. A TM4 Sertoli cell line co-incubated with the FSH-menadione conjugate in vitro exhibited significantly higher levels of mitochondrial ROS generation (10-fold), lipid peroxidation (2-fold) and oxidative DNA damage (2-fold) than the vehicle control. Additionally, in a proof-of-concept study, ten weeks after a single injection of the FSH-menadione conjugate in vivo, injected male mice were found to exhibit a 1.6 fold increase in DNA double strand breaks and 13-fold increase in oxidative DNA damage to their spermatozoa while still retaining their ability to initiate a pregnancy. We suggest this model could now be used to study the influence of chronic oxidative stress on testicular function with emphasis on the impact of DNA damage in the male germ line on the mutational profile and health of future generations.

Hepatotoxic effect of dietary phytoestrogens on juvenile cultured Russian sturgeon (Acipenser gueldenstaedtii)

In the last two decades, much controversy has grown over the use of soybean products in aquafeeds, especially for carnivorous fish like sturgeons. One point of discussion is the effect of soybean phytoestrogens on fish health. There are many aspects of phytoestrogen utilization in aquafeeds, therefore, the aim of this study is to verify if common legume phytoestrogens can affect juvenile cultured sturgeon erythrocyte and hepatocyte genotoxicity and cause liver pathology. Russian sturgeons were fed from 100 till 365 dph11Days post hutching. with daidzein, genistein, and coumestrol supplemented diets in concentrations: 10, 0.05 and 0.001 g kg−1 of feed, respectively. The SCGE22Single Cell Gel Electrophoresis (comet assay). method combined with qPCR of three genes involved in DNA repair and genome maintenance, namely cyp1a1, gaad45a and p53 were analyzed. The results were compared with histopathological evaluation of liver tissue. In fish fed with coumestrol supplemented diet, DNA strand damage was the highest in both erythrocytes and hepatocytes, however, simultaneously the lowest level of oxidative DNA damage was found. Additionally, slightly elevated expression of the p53 gene was observed along with a decreased number of apoptotic hepatocytes, which suggests that low concentration of coumestrol may support DNA repair mechanisms in the liver. Although, daidzein showed a preventive effect only against fibrosis. Isoflavones did not show a significant effect on DNA damage in studied cells. Genistein was found to increase macro- and microvesicular steatosis, portal hepatitis and fibrosis, indicating its negative role in the development of liver injuries. Daidzein alleviated some sturgeon liver damage, especially macrovesicular steatosis and interface hepatitis. However, it increased hepatocyte apoptosis, which may suggest daidzein potentially inducing liver injury, though not manifested by other histopathological lesions. Therefore, it can be concluded that at given concentrations, the tested phytoestrogens did not show clearly hepatoprotective effect in sturgeons.

Construction of Models To Predict the Effectiveness of E-Waste Control through Capture of Volatile Organic Compounds and Metals/Metalloids Exposure Fingerprints: A Six-Year Longitudinal Study.

The significant health implications of e-waste toxicants have triggered the global tightening of regulation on informal e-waste recycling sites (ER) but with disparate governance that requires effective monitoring. Taking advantage of the opportunity to implement e-waste control in the Guiyu ER since 2015, we investigated the temporal variations in levels of oxidative DNA damage, 25 volatile organic compound metabolites (VOCs), and 16 metals/metalloids (MeTs) in urine in 918 children between 2016 and 2021 to demonstrate the effectiveness of e-waste control in reducing population exposure risks. The hazard quotients of most MeTs and levels of 8-hydroxy-2'-deoxyguanosine in children decreased significantly during this time, indicating that e-waste control effectively reduces the noncarcinogenic risks of MeT exposure and levels of oxidative DNA damage. Using mVOC-derived indexes as a feature, a bagging-support vector machine algorithm-based machine learning model was constructed to predict the extent of e-waste pollution (EWP). The model exhibited excellent performance with accuracies >97.0% in differentiating between slight and severe EWP. Five simple functions established using mVOC-derived indexes also had high accuracy in predicting the presence of EWP. These models and functions provide a novel human exposure monitoring-based approach for assessing e-waste governance or the presence of EWP in other ERs.

#2629 ROS-SCAVENGING BLOCKS GLUCOSE INDUCED OXIDATIVE PERITONEAL CELL DAMAGE IN VITRO

Abstract Background and Aims Peritoneal dialysis (PD) is an effective method of renal replacement therapy (RRT). The long-term use of PD as RRT is limited due to adverse effects of high glucose-based PD fluids (PDFs) to the structure and function of the peritoneal membrane. Our group recently elucidated one pathological mechanism showing that glucose-based PDFs enhance oxidative DNA-damage in PD patients due to reduced thioredoxin (TRX) activity trigged by thioredoxin-interacting-protein (TXNIP) upregulation (Oberacker et al., 2022). Therefore, the aim of this in vitro study was to investigate drug treatments to mitigate oxidative stress and oxidative DNA-damage due to glucose-dependent induction of TXNIP expression. Method Using a mesotheliomal cell line (NCl-H28, ATCC) we performed in vitro studies mitigating reactive oxygen species (ROS) production and oxidative DNA damage as well. Cells were treated for three and eight hours with high-glucose media (1.5%, 2.3% and 4.25% glucose; glucose concentrations were adapted to PDFs from Fresenius Medical Care) compared to control media (normal glucose concentration). mRNA expression of TXNIP, TRX and further redox-related genes like superoxide dismutases (SODs) or catalase were analyzed by qPCR. Since TRX is negatively regulated by TXNIP, we investigated TRX activity in cell lysates. ROS production was monitored using a bioluminescent assay and immunofluorescence using the redox dye CellRoxGreen as well. The content of oxidative DNA-damage was investigated by immunofluorescence. Furthermore, we have preliminary analysis using primary human peritoneal mesothelial cells derived from PD effluent (PDF). Results We demonstrated a dose-dependent upregulation of round 1.5 fold TXNIP expression on mRNA level. However, no change in the expression of TRX, SODs and catalase could be observed. Interestingly, we observed a 20% reduction in TRX activity upon glucose stimulation compared to cells treated with control media. These findings are consistent with the previously published data on human peritoneal biopsies. Beyond, we demonstrated a dose-dependent increase in ROS production and increase in oxidative DNA-damage. However, ROS production and oxidative DNA damage could be prevented upon pre-incubation with the ROS-scavenger N-acetylcysteine (NAC). Conclusion Here, we show that enhanced levels of ROS and oxidative DNA damage due to glucose induced TXNIP expression could be diminished using ROS scavengers. These findings show that further antioxidative substances may be potential drugs, which could also be potential drug candidates for use in clinical practice to treat PD patients.