8-OHdG Concentrations Research Articles

Dietary supplementation of quercetin nanoparticles enhances the growth performance hematological and immunological responses and resistance to Aeromonas hydrophila infection in Nile tilapia (Oreochromis niloticus) exposed to silver nanoparticles toxicity

The wide incorporation of silver nanoparticles (AgNPs) in aquaculture could result in releasing of these particles into the environment with environmental impacts and health hazards. Thus, this study aimed to investigate the impacts of the dietary supplementation of quercetin nanoparticles (QNPs) on Nile tilapia (Oreochromis niloticus) growth, antioxidants, and immunity besides its susceptibility to the infection with Aeromonas hydrophila with or without the aqueous exposure to AgNPs. First, the 96-h LC50 value for AgNPs in O. niloticus wa estimated to be 19.81 mg/L (the 1/10th of the 96 h LC50 of AgNPs = 1.98 mg/L). Then a total of 240 Nile tilapias (40.00 ± 0.45 g) were randomly distributed into 4 groups (each group contains 60 fish in 3 replicates of 20 fish). The 1st group (control) was fed on a basal diet without QNPs and AgNPs. The 2nd group (QNPs) received the basal diet supplemented with QNPs (400 mg/kg), the 3rd group (AgNPs) was exposed to 1/10th 96-h LC50 of AgNPs (1.98 mg/L) and fed on QNPs free diet, while the 4th group (AgNPs+ QNPs) was exposed to AgNPs (1.98 mg/L) and co-supplemented with QNPs (400 mg/kg). Besides, AgNPs resulted in marked elevation in the serum myeloperoxidase (MPO) 8-hydroxy-2-deoxyguanosine (8-OHdG) contents, and declines in lysozyme activity and the levels of nitric oxide (NO) and immunoglobulins (IgM and IgG) in the exposed fish (AgNPs group). These effects were accompanied with significant downregulation in the relative mRNA expressions of SOD, CAT, and GSH and upregulation in the expressions of INF-γ, TNF-α, and Il-1β. Feeding QNPs-enriched diet, alone or combined with AgNPs exposure, conversed most of these effects and restored some to the control levels. AgNPs exposure increased mortalities, lowered survival rates and altered Nile tilapia’s resistance to A. hydrophila infection in the AgNPs exposed fish, whereas co-supplementation with QNPs enhanced their resistance with less mortalities. In summary, the reported immunomodulation, and protective properties of QNPs dietary supplementation, strengthen its applicability as an effective and promising feed supplement to alleviate the AgNPs associated toxicity in fish.

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.

SAT515 Searching For Markers To Identify Angioinvasion In Papillary Thyroid Cancer

Abstract Disclosure: A. Buczyńska: None. M. Kościuszko: None. I. Sidorkiewicz: None. A. Wiatr: None. K. Siewko: None. A. Adamska: None. A. Krętowski: None. A. Popławska-Kita: None. The incidence of Papillary Thyroid Cancer (PTC) has increased significantly over last decades. Despite the great progress in PTC clinical management, the association of angioinvasion with tumor aggressiveness in PTC remains as significant clinical problem, suggesting worse patients prognosis. Therefore cancer metastasis occurs through cell detachment and angioinvasion, epithelial–mesenchymal transition (EMT) and cell migration, changes in cell morphology are initiated through Rho-GTPase-dependent actin cytoskeleton polymerization. 8-hydroxydeoxyguanosine (8-OHdG) is generated accordingly to increased oxidative stress, however has been characterized by paradoxical anti-oxidative, anti-inflammatory and anti-mutagenic effects following Rho-GTPase inhibition, which were noted in various cancer models. Since oxidative stress has been recognized as one of the main risk factors for thyroid cancer development and progression, the total oxidative and antioxidant capacities may also be potentially involved in the process of angioinvasion. Regardless, the identification of angioinvasion in PTC remains controversial mainly due to loose criteria in judging vascular invasion. Thus, searching for laboratory biomarkers of angioinvasion is of paramount importance.In this study, the potential screening utility of oxidative stress-related markers, such as total oxidative capacity (TOC), total antioxidant capacity (TAC) and 8-OHdG was assessed to identify angioinvasion in PTC patients.For the purpose od this study, 50 patients diagnosed with angioinvasive PTC (study group) and 50 patients with very low risk PTC (control group) were enrolled. The TOC, TAC and 8-OHdG concentrations were evaluated using enzyme-linked immunosorbent assay (ELISA). Following the received results, the TAC and 8-OHdG concentrations were decresed among study group comparing to control group (p<0.001; p<0.02, respectively). However, there were no differences in TOC among studied groups (p>0.05). The AUC values for TAC=0.76 and AUC for 8-OHdG= 0.70 (all, p<0.05) suggest their screening utility. The results indicate that angioinvasion process is associated with decreased antioxidant defense in PTC patients which may insight new medical targets in the future. Presentation Date: Saturday, June 17, 2023

Fluopicolide-Induced Oxidative Stress and DNA Damage in the Earthworm Eisenia foetida.

Fluopicolide is a new benzamide fungicide with a unique mechanism of action and is toxic to some non-target organisms. However, there is a lack of research on the chronic toxicity of fluopicolide to earthworms. In this study, in order to evaluate the chronic toxicity of fluopicolide to earthworms, the levels of reactive oxygen species (ROS) and malondialdehyde (MDA), the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione S-transferase (GST), and DNA oxidative damage (8-hyoxy-2-deoxyguanosine content) in earthworms were measured at 7, 14, 21, and 28 days after exposure to different concentrations (0, 0.1, 0.5, 1, 2.5, 5, and 10 mg/kg) of fluopicolide. In most treatment groups, the ROS levels increased significantly 7 days after exposure and then decreased gradually with an increase in exposure time, a certain dose-effect relationship. The antioxidant enzymes' activities (SOD and CAT) in most treatment groups were activated, showing an increasing trend at first and then a decreasing trend; however, the CAT activity in the high-concentration treatment group was inhibited 21 days after exposure. The GST activity and MDA content showed an increasing trend at first and then a decreasing trend, which was dependent on the dose. As a biomarker of DNA damage, the 8-OHdG content was positively correlated with the concentration of fluopicolide. The results showed that a low dose of fluopicolide could cause oxidative stress and DNA damage in earthworms.

Exposure to Benzo[a]pyrene and 1-Nitropyrene in Particulate Matter Increases Oxidative Stress in the Human Body.

Polycyclic aromatic hydrocarbons (PAHs) have been reported to cause oxidative stress in metabolic processes. This study aimed to evaluate the relationship between exposure to PAHs, including benzo[a]pyrene (BaP) and 1-nitropyrene (1-NP), in the atmosphere and oxidative stress levels in the human body. This study included 44 Korean adults who lived in Cheongju, Republic of Korea. Atmospheric BaP and 1-NP concentrations and urinary 6-hydroxy-1-nitropyrene (6-OHNP), N-acetyl-1-aminopyrene (1-NAAP), and 1-hydroxypyrene (1-OHP) concentrations were measured. The oxidative stress level was assessed by measuring urinary thiobarbituric acid-reactive substances (TBARS) and 8-hydroxydeoxyguanosine (8-OHdG) concentrations. Urinary TBARS and 6-OHNP concentrations significantly differed between winter and summer. BaP exposure was significantly associated with urinary 8-OHdG concentrations in summer. However, atmospheric 1-NP did not show a significant correlation with oxidative stress marker concentrations. Urinary 1-NAAP concentration was a significant determinant for urinary 8-OHdG concentration in summer. Oxidative stress in the body increases in proportion to inhalation exposure to BaP, and more 8-OHdG is produced in the body as the amount of 1-NP, which is metabolized to 1-AP or 1-NAAP, increases.

Leukocyte 8-hydroxy-2'-deoxyguanosine as an oxidative stress marker to predict cardiovascular events and death in chronic hemodialysis patients.

Hemodialysis patients have a markedly increased risk of cardiovascular (CV) morbidity and mortality. Oxidative stress plays a pathogenic role in the progression of atherosclerosis and CV disease among chronic hemodialysis patients. The 8-hydroxy-2'-deoxyguanosine (8-OHdG) content in leukocyte deoxyribonucleic acid (DNA) has been shown as a sensitive and well-known biomarker of oxidant-induced DNA damage in chronic hemodialysis patients. We conducted a retrospective cohort study to investigate the association of leukocyte 8-OHdG and CV events and deaths in patients of chronic hemodialysis. In this study, 217 chronic hemodialysis patients were recruited from 2016 to 2021. The 8-OHdG content of leukocyte DNA was measured by a high-performance liquid chromatography electrochemical detection method. Study outcomes were CV events as well as CV and all-cause deaths. The patients were followed until May 2021. The median follow-up period was 34.8 months. At the end of May 2021, 57 first CV events and 89 all-CV events occurred. Among the first and all CV events, 17 (29.8%) and 32 (36.0%) were fatal, respectively. Multivariate Cox regression analysis showed per 1/10 5 dG increment in leukocyte 8-OHdG values increased risk of CV events (adjusted hazard ratio [aHR], 1.19; 95% CI, 1.10-1.41; p < 0.001), CV death (aHR, 1.27; 95% CI, 1.03-1.72; p = 0.034), and all-cause death (aHR, 1.11; 95% CI, 1.01-1.30; p = 0.038). This is the first study to demonstrate that oxidative stress assessed by 8-OHdG levels of leukocyte DNA predicted CV events as well as CV and all-cause deaths among chronic hemodialysis patients.

Cytotoxicity induced by abamectin in hepatopancreas cells of Chinese mitten crab, Eriocheir sinensis: An in vitro assay

Toxic effects of abamectin on non-target aquatic organisms have been well documented due to its extensive use in both agricultural and aquacultural areas. However, knowledge of the abamectin induced cytotoxicity in crustacean hepatopancreas is still incomplete. In this study, we investigated the cytotoxic effects of abamectin on hepatopancreas cells of Chinese mitten crab, Eriocheir sinensis by an in vitro assay. The results showed that abamectin inhibited cell viability with elevated reactive oxygen species (ROS) and malondialdehyde (MDA) levels in a dose-dependent manner. Increased olive tail moment (OTM) values and 8-hydroxy-2′-deoxyguanosine (8-OHdG) contents indicate the DNA damage under abamectin exposure. The up-regulation of the typical apoptosis-related protein BCL2-associated X protein (Bax) and the down-regulation of B cell leukemia/lymphoma 2 (Bcl-2) demonstrate apoptosis in hepatopancreas cells. Meanwhile, the activities of both caspase-3 and caspase-9 were increased, indicating caspase-mediated apoptosis. In addition, qRT-PCR results showed the up-regulation of antioxidant genes superoxide dismutase (SOD) and catalase (CAT). The mRNA expression of Cap ‘n′ Collar isoform-C (CncC) and c-Jun NH2-terminal kinases (JNK) was also significantly increased, implying the involvement of the Nrf2/MAPK pathway in the antioxidative response. The alteration of innate immune-associated genes Toll-like receptor (TLR) and myeloid differentiation primary response gene 88 (Myd88) also indicates the influence of abamectin on immune status. In summary, the present study reveals the cytotoxicity of abamectin on hepatopancreas cells of E. sinensis and this in vitro cell culture model could be used for further assessment of pesticide toxicity.

Plasma 8-Hydroxy-2'-Deoxyguanosine, a Potential Valuable Biomarker for Atrial Fibrosis Is Influenced by Polymorphism of DNA Methylation Gene.

Previous studies revealed a relationship between 8-hydroxy-2'-deoxyguanosine (8-OHdG) and the occurrence/recurrence of atrial fibrillation (AF). This 2-part study aimed to validate whether DNA damage related to 8-OHdG is associated with left atrial (LA) fibrosis in AF patients quantified by voltage mapping (Part I), and to identify the underlying genetic components regulating the 8-OHdG level (Part II).Methods and Results: Plasma 8-OHdG determination, DNA extraction, and genotyping were conducted before catheter ablation. LA voltage mapping was performed under sinus rhythm. According to the percentage of low voltage area (LVA), patients were categorized as stage I (<5%), stage II (5-10%), stage III (10-20%), and stage IV (>20%). Part I included 209 AF patients. The 8-OHdG level showed an upward trend together with advanced LVA stage (stage I 8.1 [6.1, 10.5] ng/mL, stage II 8.5 [5.7, 14.1] ng/mL, stage III 14.3 [12.1, 16.5] ng/mL, stage IV 13.9 [10.5, 16.0] ng/mL, P<0.000). Part II included 175 of the 209 patients from Part I. Gene-set analysis based on genome-wide association study summary data identified that the gene set named 'DNA methylation on cytosine' was the only genetic component significantly associated with 8-OHdG concentration. Higher 8-OHdG levels may predict more advanced LVA of the LA in AF patients. DNA methylation is the putative genetic component underlying oxidative DNA damage in AF patients.

#6546 RENAL TUBULAR TOXICITY OF ORGANOPHOSPHATE FLAME RETARDANTS IN PATIENTS WITH CHRONIC KIDNEY DISEASE

Abstract Background and Aims Organophosphate flame retardants (OPFRs) are widely utilized flame retardants and considered less harmful than legacy brominated flame retardants. However, owing to their widespread utilization, OPFRs have led to extensive and persistent human exposure, with potentially hazardous effects on human health such as nephrotoxicity. Experimental and clinical studies have revealed that OPFR exposure is associated with renal tubular toxicity and renal impairment. However, the nephrotoxic mechanisms of OPFRs have not yet been clarified, and their impact on renal tubular injury has less been evaluated in patients with chronic kidney disease (CKD). In this cross-sectional observational study, we assessed the urinary OPFR concentrations in CKD patients to evaluate the associations between OPFR exposure and renal tubular injury in this population. Method Adult CKD patients in Taiwan (≥ 20 years of age and with non-dialysis-dependent CKD stage 3–5) were recruited from the Kaohsiung Chang Gung Memorial Hospital between January 2020 and May 2021. The first-void urine samples in the morning were collected to measure the concentrations of 10 common OPFR compounds using an ultra-performance liquid chromatography-tandem mass spectrometry (Waters, Milford, MA, USA). The urinary novel renal biomarkers were also measured using enzyme-linked immunosorbent assays (kidney injury molecule-1 [KIM1] and 8-hydroxy-2-deoxyguanosine [8-OHdG]; Abcam, Trumpington, Cambridge, UK). OPFRs with concentrations below a limit of quantitation (LOQ) were considered undetectable, and LOQ/√2 was assigned to the non-detected samples for analysis. The associations between urinary renal biomarkers and ΣOPFR concentrations (i.e., the sum of 10 OPFR compounds) were assessed via Spearman's correlation analysis. Simple linear regression analyses were conducted to evaluate the correlations between urinary renal biomarkers, ΣOPFR concentrations, and baseline patient characteristics. The effects of OPFR exposure on the urinary concentrations of KIM-1 and 8-OHdG in the enrolled CKD patients were examined in multiple linear regression analyses, adjusting for age, sex, body mass index, diabetes, hypertension, renal function, proteinuria, and covariates with a p-value &amp;lt; 0.1 in univariate analyses via the enter method. Results In this study, 163 CKD patients were enrolled for analysis (stage 3: n = 79 [49.47%]; stage 4: n = 48 [29.45%]; stage 5: n = 36 [22.08%]). The overall detection frequency of urinary OPFRs was 98.77% in the study cohort, with a median ΣOPFR of 2.04 μg/g Cr (interquartile range [IQR], 0.84–4.27). The median urinary KIM-1 and 8-OHdG concentrations were 185.89 ng/g Cr (IQR, 83.05–441.60) and 71.23 μg/g Cr (IQR, 37.87–149.73), respectively. In our analysis, urinary ΣOPFR concentrations were positively correlated with urinary KIM-1 and 8-OHdG concentrations (rs = 0.267 for KIM-1, p = 0.001; rs = 0.281 for 8-OHdG, p &amp;lt; 0.001) (Figure 1). In the multiple linear regression analyses, urinary ΣOPFR concentration was identified as an independent predictor positively associated with urinary renal biomarkers in the enrolled patients, with a 0.260 log ng/g Cr (95% confidence interval [CI], 0.140–0.380, p &amp;lt; 0.001) increase in urinary KIM1 and a 0.227 log μg/g Cr elevation (95% CI, 0.124–0.330, p &amp;lt; 0.001) in urinary 8-OHdG by per log μg/g Cr ΣOPFR (Figure 2). Conclusion OPFR exposure is common and associated with renal tubular injury as well as increased oxidative stress in CKD patients, which highlights its nephrotoxic potential in this vulnerable population.

Yeast polysaccharide mitigated oxidative injury in broilers induced by mixed mycotoxins via regulating intestinal mucosal oxidative stress and hepatic metabolic enzymes

This study was aimed to investigate the effects of yeast polysaccharides (YPS) on growth performance, intestinal health, and aflatoxin metabolism in livers of broilers fed diets naturally contaminated with mixed mycotoxins (MYCO). A total of 480 one-day-old Arbor Acre male broilers were randomly allocated into a 2×3 factorial arrangement of treatments (8 replicates with 10 birds per replicate) for 6 wk to assess the effects of 3 levels of YPS (0, 1, or 2 g/kg) on the broilers fed diets contaminated with or without MYCO (95 μg/kg aflatoxin B1, 1.5 mg/kg deoxynivalenol, and 490 μg/kg zearalenone). Results showed that mycotoxins contaminated diets led to significant increments in serum malondialdehyde (MDA) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels, mRNA expressions of TLR4 and 4EBP1 associated with oxidative stress, mRNA expressions of CYP1A1, CYP1A2, CYP2A6, and CYP3A4 associated with hepatic phase Ⅰ metabolizing enzymes, mRNA expressions of p53 associated with hepatic mitochondrial apoptosis, and AFB1 residues in the liver (P < 0.05); meanwhile dietary MYCO decreased the jejunal villus height (VH), villus height/crypt depth (VH/CD), the activity of serum total antioxidant capacity (T-AOC), mRNA expressions of jejunal HIF-1α, HMOX, and XDH associated with oxidative stress, mRNA expressions of jejunal CLDN1, ZO1, and ZO2, and mRNA expression of GST associated with hepatic phase Ⅱ metabolizing enzymes of broilers (P < 0.05). Notably, the adverse effects induced by MYCO on broilers were mitigated by supplementation with YPS. Dietary YPS supplementation reduced the concentrations of serum MDA and 8-OHdG, jejunal CD, mRNA expression of jejunal TLR2, and 4EBP1, hepatic CYP1A2, and p53, and the AFB1 residues in the liver (P < 0.05), and elevated the serum T-AOC and SOD, jejunal VH, and VH/CD, and mRNA expression of jejunal XDH, hepatic GST of broilers (P < 0.05). There were significant interactions between MYCO and YPS levels on the growth performance (BW, ADFI, ADG, and F/G) at d 1 to 21, d 22 to 42, and d 1 to 42, serum GSH-Px activity, and mRNA expression of jejunal CLDN2 and hepatic ras of broilers (P < 0.05). In contrast with MYCO group, the addition of YPS increased BW, ADFI, and ADG, the serum GSH-Px activity (14.31%-46.92%), mRNA levels of jejunal CLDN2 (94.39%-103.02%), decreased F/G, and mRNA levels of hepatic ras (57.83%-63.62%) of broilers (P < 0.05). In conclusion, dietary supplements with YPS protected broilers from mixed mycotoxins toxicities meanwhile keeping normal performance of broilers, presumably via reducing intestinal oxidative stress, protecting intestinal structural integrity, and improving hepatic metabolic enzymes to minimize the AFB1 residue in the liver and enhance the performance of broilers.

Shorter telomere length in children with autism spectrum disorder is associated with oxidative stress.

Autism spectrum disorder (ASD) is a highly heterogeneous neurodevelopmental disorder caused by a complex interaction between genetic and environmental risk factors. The balance between antioxidant capacity and oxidative stress (OS) induced free radicals may be crucial during the pathophysiological development of ASD. In this study, 96 children with ASD who met the diagnostic and statistical manual of mental disorders were collected, and the number of children in the typical development (TD) group was matched by 1:1. Digital PCR (dPCR) for telomere length (TL) expression in ASD in peripheral blood leukocytes. Urine levels of 8-hydroxy-2-deoxyguanosine (8-OHdG) content were measured by tandem triple quadrupole mass spectrometry and corrected by urinary creatinine levels. The levels of superoxide dismutase (SOD), catalase (CAT), and capacity (AOC) were detected by kits. The TL of the ASD group was shorter than the TD group (p < 0.01) and had some accurate predictive significance for the identification of ASD (AUC = 0.632, 95% CI: 0.533-0.710, p = 0.002). Both 8-OHdG content and SOD activity in the ASD group were significantly higher than those in the TD group (p < 0.05). Shortened TL (Monofactor: 2.20 (1.22, 3.96), p = 0.009; Multifactor: 2.22 (1.22, 4.00), p = 0.008) and reduced CAT activity (Monofactor: 2.31 (1.28, 4.17), p = 0.006; Multifactor: 2.31 (1.28, 4.18), p = 0.006) are risk factors for the development of ASD, while reduced 8-OHdG content (Monofactor: 0.29 (0.14, 0.60), p = 0.001; Multifactor: 0.27 (0.13, 0.57), p = 0.001) and reduced SOD activity (Monofactor: 0.55 (0.31, 0.98), p = 0.042; Multifactor: 0.54 (0.30, 0.98), p = 0.042) are protective factors for the development of ASD. In this study, TL and OS were significantly different between the ASD group and the TD group. As guanine-rich telomere sequences were likely damaged by oxygen free radicals, creating OS, which is a factor in the incidence and progression of ASDs. In conclusion, oxidative damage occurs in the bodies of children with ASD, which may lead to sustained disease progression and severe clinical manifestations. We assume that timely supplementation of antioxidants is very likely to be a potential treatment for early intervention in children with ASD. Identification and detection of OS-related biomarkers may contribute to early diagnosis and timely interventions in young patients with ASD.

8-Hydroxy-2'-deoxyguanosine and malondialdehyde in plasma and their association with disease severity in 20 cats with chronic kidney disease.

Oxidative stress is associated with the development and progression of chronic kidney disease (CKD) in humans. The aim of this study was to evaluate the concentrations of oxidative stress markers, 8-hydroxy-2'-deoxyguanosine (8-OHdG) and malondialdehyde (MDA), in the plasma and urine of cats with different stages of CKD. Plasma and urine samples were collected from cats with CKD that were referred to the Veterinary Medical Center of the University of Tokyo between April 2019 and October 2022. Plasma and urine samples were collected from healthy cats (n = 6 at most), cats with stage 2 CKD (n = 8) and stage 3-4 CKD (n = 12), and cats with idiopathic cystitis (disease control, n = 5). Plasma and urine concentrations of 8-OHdG and MDA were measured using ELISA and thiobarbituric acid reactive substances assay kits, respectively. The median plasma 8-OHdG concentrations were 0.156 ng/ml (<0.125-0.210 ng/ml) in the healthy group, <0.125 ng/ml (range <0.125 ng/ml) in the idiopathic cystitis group, 0.246 ng/ml (range 0.170-0.403 ng/ml) in cats with stage 2 CKD and 0.433 ng/ml (range 0.209-1.052 ng/ml) in cats with stage 3-4 CKD. Concentrations in stage 3-4 CKD were significantly higher than those in the healthy and disease control groups. Plasma MDA concentrations were low in the healthy and disease control groups and significantly higher in cats with stage 3-4 CKD. In every cat with CKD, plasma 8-OHdG and MDA concentrations were positively correlated with plasma creatinine concentrations (8-OHdG, rs = 0.68; MDA, rs = 0.67). Urinary 8-OHdG/urinary creatinine (u-CRE) and urinary MDA/u-CRE levels did not differ significantly between the groups; however, it was difficult to evaluate them because of the small sample size. This report shows that plasma 8-OHdG and MDA concentrations increase with the severity of feline CKD. These markers may be useful for assessing oxidative stress in cats with CKD.

Role and mechanism of SIRT1 in regulating Nrf2/HO-1 signaling pathway in septic liver injury

To investigate the role and mechanism of silent information regulator 1 (SIRT1) in regulating nuclear factor E2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway in oxidative stress and inflammatory response to sepsis-induced liver injury. A total of 24 male Sprague-Dawley (SD) rats were randomly divided into sham operation (Sham) group, cecal ligation and puncture (CLP) group, SIRT1 agonist SRT1720 pretreatment (CLP+SRT1720) group and SIRT1 inhibitor EX527 pretreatment (CLP+EX527) group, with 6 rats in each group. Two hours before operation, SRT1720 (10 mg/kg) or EX527 (10 mg/kg) were intraperitoneally injected into the CLP+SRT1720 group and CLP+EX527 group, respectively. Blood was collected from the abdominal aorta at 24 hours after modeling and the rats were sacrificed for liver tissue. The serum levels of interleukins (IL-6, IL-1β) and tumor necrosis factor-α (TNF-α) were detected by enzyme-linked immunosorbent assay (ELISA). The serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were detected by microplate method. Hematoxylin-eosin (HE) staining was used to observe the pathological injury of rats in each group. The levels of malondialdehyde (MDA), 8-hydroxydeoxyguanosine (8-OHdG), glutathione (GSH) and superoxide dismutase (SOD) in liver tissue were detected by corresponding kits. The mRNA and protein expressions of SIRT1, Nrf2 and HO-1 in liver tissues were detected by real-time quantitative polymerase chain reaction (RT-qPCR) and Western blotting. Compared with the Sham group, the serum levels of IL-6, IL-1β, TNF-α, ALT and AST in the CLP group were significantly increased; histopathological results showed that liver cords were disordered, hepatocytes were swollen and necrotic, and a large number of inflammatory cells infiltrated; the contents of MDA and 8-OHdG in liver tissue increased, while the contents of GSH and SOD decreased; and the mRNA and protein expressions of SIRT1, Nrf2 and HO-1 in liver tissues were significantly decreased. These results suggest that sepsis rats have liver dysfunction, and the levels of SIRT1, Nrf2, HO-1 and antioxidant protein in liver tissues were decreased, while the levels of oxidative stress and inflammation were increased. Compared with the CLP group, the levels of inflammatory factors and oxidative stress were significantly decreased in the CLP+SRT1720 group, the mRNA and protein expressions of SIRT1, Nrf2 and HO-1 were significantly increased [IL-6 (ng/L): 34.59±4.21 vs. 61.84±3.78, IL-1β (ng/L): 41.37±2.70 vs. 72.06±3.14, TNF-α (ng/L): 76.43±5.23 vs. 130.85±5.30, ALT (U/L): 30.71±3.63 vs. 64.23±4.59, AST (U/L): 94.57±6.08 vs. 145.15±6.86, MDA (μmol/g): 6.11±0.28 vs. 9.23±0.29, 8-OHdG (ng/L): 117.43±10.38 vs. 242.37±11.71, GSH (μmol/g): 11.93±0.88 vs. 7.66±0.47, SOD (kU/g): 121.58±5.05 vs. 83.57±4.84, SIRT1 mRNA (2-ΔΔCt): 1.20±0.13 vs. 0.46±0.02, Nrf2 mRNA (2-ΔΔCt): 1.21±0.12 vs. 0.58±0.03, HO-1 mRNA (2-ΔΔCt): 1.71±0.06 vs. 0.48±0.07, SIRT1 protein (SIRT1/β-actin): 0.89±0.04 vs. 0.58±0.03, Nrf2 protein (Nrf2/β-actin): 0.87±0.08 vs. 0.51±0.09, HO-1 protein (HO-1/β-actin): 0.93±0.14 vs. 0.54±0.12, all P < 0.05], these results indicated that SIRT1 agonist SRT1720 pretreatment could improve liver injury in sepsis rats. However, pretreatment with SIRT1 inhibitor EX527 showed the opposite effect [IL-6 (ng/L): 81.05±6.47 vs. 61.84±3.78, IL-1β (ng/L): 93.89±5.83 vs. 72.06±3.14, TNF-α (ng/L): 177.67±5.12 vs. 130.85±5.30, ALT (U/L): 89.33±9.52 vs. 64.23±4.59, AST (U/L): 179.59±6.44 vs. 145.15±6.86, MDA (μmol/g): 11.39±0.51 vs. 9.23±0.29, 8-OHdG (ng/L): 328.83±11.26 vs. 242.37±11.71, GSH (μmol/g): 5.07±0.34 vs. 7.66±0.47, SOD (kU/g): 59.37±4.28 vs. 83.57±4.84, SIRT1 mRNA (2-ΔΔCt): 0.34±0.03 vs. 0.46±0.02, Nrf2 mRNA (2-ΔΔCt): 0.46±0.04 vs. 0.58±0.03, HO-1 mRNA (2-ΔΔCt): 0.21±0.03 vs. 0.48±0.07, SIRT1 protein (SIRT1/β-actin): 0.47±0.04 vs. 0.58±0.03, Nrf2 protein (Nrf2/β-actin): 0.32±0.07 vs. 0.51±0.09, HO-1 protein (HO-1/β-actin): 0.19±0.09 vs. 0.54±0.12, all P < 0.05]. SIRT1 can inhibit the release of proinflammatory factors and alleviate the oxidative damage of hepatocytes by activating Nrf2/HO-1 signaling pathway, thus playing a protective role against CLP-induced liver injury.

Developmental toxicity of black phosphorus quantum dots in zebrafish (Danio rerio) embryos

Nanomaterials have attracted much attention in the biomedical field. Black phosphorus quantum dots (BPQDs) have shown great potential in biomedical applications, but their potential risks to biosafety and environmental stability have not been fully evaluated. In the present study, zebrafish (Danio rerio) embryos were exposed to 0, 2.5, 5 and 10 mg/L BPQDs from 2 to 144 h post-fertilization (hpf) to explore developmental toxicity. The results showed that exposure to BPQDs for 96 h induced developmental malformations (tail deformation, yolk sac edema, pericardial edema, and spinal curvature) in zebrafish embryos. ROS and antioxidant enzyme activities (CAT, SOD, MDA and T-AOC) were substantially altered and the acetylcholinesterase (AChE) enzyme activity was significantly decreased in the BPQDs exposed groups. Locomotor behavior was inhibited after BPQDs exposure for 144 h in zebrafish larvae. A significant increase in 8-OHdG content indicates DNA oxidative damage in embryos. In addition, obvious apoptotic fluorescence signals were detected in the brain, spine, yolk sac and heart. At the molecular level, the mRNA transcript levels of key genes related to skeletal development (igf1, gh, MyoD and LOX), neurodevelopment (gfap, pomca, bdnf and Mbpa), cardiovascular development (Myh6, Nkx2.5, Myl7, Tbx2b, Tbx5 and Gata4) and apoptosis (p53, Bax, Bcl-2, apaf1, caspase-3 and caspase-9) were abnormal after BPQDs exposure. In conclusion, BPQDs induced morphological malformations, oxidative stress, locomotor behavior disorders, DNA oxidative damage and apoptosis in zebrafish embryos. This study provides a basis for further study on the toxic effects of BPQDs.

The influence of the co-exposure to polycyclic aromatic hydrocarbons and toxic metals on DNA damage in brazilian lactating women and their infants: A cross-sectional study using machine learning approaches

Polycyclic aromatic hydrocarbons (PAHs) and toxic metals are widely spread pollutants of public health concern. The co-contamination of these chemicals in the environment is frequent, but relatively little is known about their combined toxicities. In this context, this study aimed to evaluate the influence of the co-exposure to PAHs and toxic metals on DNA damage in Brazilian lactating women and their infants using machine learning approaches. Data were collected from an observational, cross-sectional study with 96 lactating women and 96 infants living in two cities. The exposure to these pollutants was estimated by determining urinary levels of seven mono-hydroxylated PAH metabolites and the free form of three toxic metals. 8-Hydroxydeoxyguanosine (8-OHdG) levels in the urine were used as the oxidative stress biomarker and set as the outcome. Individual sociodemographic factors were also collected using questionnaires. Sixteen machine learning algorithms were trained using 10-fold cross-validation to investigate the associations of urinary OH-PAHs and metals with 8-OHdG levels. This approach was also compared with models attained by multiple linear regression. The results showed that the urinary concentration of OH-PAHs was highly correlated between the mothers and their infants. Multiple linear regression did not show a statistically significant association between the contaminants and urinary 8OHdG levels. Machine learning models indicated that all investigated variables did not present predictive performance on 8-OHdG concentrations. In conclusion, PAHs and toxic metals were not associated with 8-OHdG levels in Brazilian lactating women and their infants. These novelty and originality results were achieved even after applying sophisticated statistical models to capture non-linear relationships. However, these findings should be interpreted cautiously because the exposure to the studied contaminants was considerably low, which may not reflect other populations at risk.

Triclosan is associated with breast cancer via oxidative stress and relative telomere length.

Triclosan (TCS), a widely prescribed broad-spectrum antibacterial agent, is an endocrine-disrupting chemical. The relationship and biological mechanisms between TCS exposure and breast cancer (BC) are disputed. We aimed to examine the correlation between urinary TCS exposure and BC risk and estimated the mediating effects of oxidative stress and relative telomere length (RTL) in the above association. This case-control study included 302 BC patients and 302 healthy individuals in Wuhan, China. We detected urinary TCS, three common oxidative stress biomarkers [8-hydroxy-2-deoxyguanosine (8-OHdG), 8-iso-prostaglandin F2α (8-isoPGF2α), 4-hydroxy-2-nonenal-mercapturic acid (HNE-MA)], and RTL in peripheral blood mononuclear cells. Significant associations were observed between log-transformed urinary concentrations of TCS, 8-OHdG, HNE-MA, 8-isoPGF2α, RTL, and BC risk, with the odds ratios (95% confidence intervals) being 1.58 (1.32-1.91), 3.08 (1.55-6.23), 3.39 (2.45-4.77), 3.99 (2.48-6.54), and 1.67 (1.35-2.09), respectively. Continuous TCS exposure was significantly positively correlated with RTL, HNE-MA, and 8-isoPGF2α (all p<0.05) but not with 8-OHdG (p = 0.060) after adjusting for covariates. The mediated proportions of 8-isoPGF22α and RTL in the relationship between TCS and BC risk were 12.84% and 8.95%, respectively (all p<0.001). In conclusion, our study provides epidemiological evidence to confirmed the deleterious effects of TCS on BC and indicated the mediating effect of oxidative stress and RTL on the correlation between TCS and BC risk. Moreover, exploring the contribution of TCS to BC can clarify the biological mechanisms of TCS exposure, provide new clues for the pathogenesis of BC, which is of great significance to improving public health systems.

Rapid extraction and analysis of oxidative stress and DNA damage biomarker 8-hydroxy-2'-deoxyguanosine (8-OHdG) in urine: Application to a study with pregnant women.

Oxidative stress is an important toxicity and genotoxicity mechanism of many chronic adverse health outcomes. This study developed a sensitive extraction method for urine matrix (based on lyophilization, without the need for pre-cleaning by solid phase extraction), coupled to LC-MS/MS analysis of the biomarker 8-hydroxy-2'-deoxyguanosine (8-OHdG). The methodology was validated in urine samples from a cohort of Spanish pregnant women collected during the first, second and third trimester of pregnancy, and urine samples collected within 24h after delivery (n=85). A detection and quantification limit of 0.01 and 0.05μg/L, respectively, were established. The median 8-OHdG concentration was 2.18μg/L (range 0.33-7.79); and the corresponding creatinine-adjusted concentrations ranged from 1.04 to 13.12 with median of 4.48μg 8-OHdG/g creatinine. The concentrations of non-adjusted 8-OHdG significantly decreased (p<0.05) in the 3rd trimester and post-delivery urine samples when compared to the 1st trimester levels. 8-OHdG concentrations were further studied in placenta samples matching the same urine samples (n=26), with a median value of 1.3ng 8-OHdG/g of tissue. Placental 8-OHdG concentrations were correlated with urinary levels of non-adjusted 8-OHdG in the 3rd trimester. Considering the small cohort size, results must be interpreted with caution, however statistical analyses revealed elevated urinary non-adjusted 8-OHdG levels in the 1st trimester of mothers that delivered boys compared to those who delivered girls (p<0.01). Increased urinary non-adjusted 8-OHdG concentrations at the time of delivery were significantly associated with clinical records (any type of clinical record during pregnancy; p<0.05). The novel extraction and analytical method for the assessment of 8-OHdG is applicable for sensitive analysis of multiple analytes or biomarkers in urine matrix. This method could also be applied for other matrices such as blood or tissues. Our findings show that 8-OHdG in urine of pregnant women could predict oxidative stress in placenta and can be related to characteristics such as maternal obesity, mode of delivery and newborn sex.

Electroacupuncture promotes expression of glutathione related regulatory enzymes in ovary tissue of rats with diminished ovarian reserve

To observe the effect of electroacupuncture (EA) on ovarian function and expression of glutathione (GSH) related regulatory enzymes γ-glutamylcysteine synthetase (γ-GCS), glutathione reductase (GR) protein and gene in rats with diminished ovarian reserve (DOR), so as to explore its mechanisms underlying up-regulation of antioxidant stress ability. A total of 30 female SD rats with normal estrous cycle were randomly divided into blank control, model and EA groups, with 10 rats in each group. The DOR model was established by gavage of tripterygium wilfordii polyglycoside suspension (50 mg·kg-1·d-1) for 14 consecutive days, while the rats in the blank group were given equal volume of 0.9% sodium chloride solution. One hour after daily gavage, EA (1.0 mA, 100 Hz) was applied alternately to bilateral "Shenshu"(BL23), and "Zhongwan"(CV12)+"Guanyuan"(CV4) for 10 min, for 14 consecutive days. Estrous cycles of rats in each group were observed and recorded daily during intervention.After the intervention, H.E.staining was used to observe histopathological changes of the ovarian tissue. The contents of serum sex hormones ［follicle stimulating hormone (FSH), anti-mullerian hormone (AMH), estradiol (E2)］ and oxidative damage markers ［8-hydroxydeoxyguanosine (8-OHDG) and nitrotyrosine (NTY)］ were determined by ELISA. The contents of GSH and oxidized glutathione (GSSG) in the liver tissue were determined by colorimetry, and their ratios were calculated. Immunohistochemistry and real-time fluorescence quantitative PCR were used to detect the immunoactivity and gene expression levels of γ-GCS and GR in the ovarian tissues, respectively. Compared with the blank group, the model group had a marked increase in the disorder rate of estrous cycle, serum FSH, 8-OHDG and NTY contents (P<0.01) and a considerable decrease in the levels of serum AMH and E2, liver GSH and GSSG contents and GSH/GSSG ratio, ovarian optical density and cell number as well as the expression of γ-GCS and GR mRNAs (P<0.05, P<0.01). After EA intervention, the increase of the disorder rate of estrous cycle, serum FSH, 8-OHDG and NTY contents and the decrease of serum AMH and E2, liver GSH and GSSG contents and GSH/GSSG ratio, ovarian optical density and cell number of γ-GCS and GR as well as the expression of γ-GCS genes were all reversed (P<0.01, P<0.05). H.E. staining showed degenerative changes of the ovarian tissue, fewer follicles at every level and increase of atretic follicles, disarrangement and layer number decrease of granulosa cells, and atrophy of corpus luteum in the model group, which were relatively milder in the EA group. EA can improve ovarian function, and reduce oxidative stress damage in DOR rats, which may be associated with its functions in up-regulating the expression of γ-GCS and GR protein and gene in the ovarian tissue.

Levels of DNA, Protein, Lipid Oxidation and Apoptosis Biomarkers in Semen of Men with Hyperviscous Semen: A Cross-Sectional Study.

Semen hyperviscosity is a threatening cause of abnormal spermatozoa and infertility in men. We aimed to evaluate oxidative stress, antioxidants depletion and sperm apoptosis as main reasons for poor quality of spermatozoa in men with hyperviscous semen. In this cross-sectional study, ejaculate specimens were collected from fertile (n=102) and infertile men with hyperviscous semen (n=123) and without semen hyperviscosity (n=143). Total antioxidant capacity (TAC), glutathione (GSH), malondialdehyde (MDA), protein carbonyl (PC), 8-hydroxydeoxyguanosine (8-OHdG), and were measured in semen samples to estimate oxidative stress status. Gene expression pattern of BAX, CASPASE-9, CASPASE-3, and BCL2 was assessed to estimate sperm apoptosis. The average of sperm count, normal morphology, normal motility, and sperm vitality in men with hyperviscous semen was significantly lower than infertile subjects without hyperviscous semen (P<0.01). Men with hyperviscous semen exhibited higher levels of PC (8.34 ± 1.03 nmol/mg vs. 6.01 ± 0.93 nmol/mg, P=0.008), MDA (1.14 ± 0.27 nmol/ ml vs. 0.89 ± 0.22 nmol/ml, P=0.031), 8-OHdG (259.71 ± 24.59 ng/ml vs. 197.13 ± 18.47 ng/ml, P=0.009), but lower TAC contents (1250.44 ± 66.23 μM/L vs. 1784.31 ± 89.87 μM/L, P=0.018) and GSH (3.82 ± 1.05 μM vs. 5.89 ± 0.87 μM, P=0.021) than men with non-viscous semen. The expression of BAX, CASPASE-3 and CASPASE-9 genes in men with hyperviscous semen was significantly increased by 1.39-fold (P=0.041), 1.47-fold (P=0.046), 1.29-fold (P=0.048), respectively, as compared with the infertile subjects without hyperviscous semen. However, BCL2 expression in infertile men without hyperviscous semen was higher compared to those with hyperviscous semen (1.36-fold, P=0.044). Hyperviscous semen is markedly associated with depletion of seminal plasma antioxidants, sperm membrane lipid peroxidation, DNA and protein oxidation, and sperm apoptosis. Antioxidant therapy might be considered as a valuable strategy to protect sperm cells against oxidative damage in cases with seminal fluid hyperviscosity.

Impact of modernization on oxidative stress among indigenous populations in northern Laos.

To explore the impact of modernization on oxidative stress during a momentous health transition process, we investigated differences in oxidative stress among the indigenous populations of villages in northern Laos with different levels of modernization. We conducted a cross-sectional study of 380 adults in three villages with different levels of modernization. Three biomarkers related to oxidative stress were measured: urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) and 8-isoprostane concentrations (both measured by liquid chromatography-tandem mass spectrometry), and blood telomere length (measured with qPCR). We examined associations between village-level modernization and oxidative stress-related biomarkers in a multilevel analysis including a random effect and covariates. The geometric means of urinary 8-OHdG and 8-isoprostane concentrations were 2.92 and 0.700 μg/g creatinine, respectively, in our study population. Higher urinary 8-OHdG concentrations and shorter telomeres were observed in participants from the more modernized villages, whereas urinary 8-isoprostane concentrations did not differ significantly among villages. Our findings imply that modernization-induced changes in lifestyle may increase oxidative DNA damage. Baseline levels of oxidative lipid damage are expected to be high in the indigenous populations of northern Laos. Assessments of oxidative stress may provide valuable insights into the mechanisms of health transition in specific populations.