Oxidative Stress Marker 8-OHdG Research Articles

Effects of WN1703 on Cardiovascular Function in Chronic Hyperuricemia Rats and Myocardial Injury Mechanism Exploration in H9C2 Cells.

Hyperuricemia, a prevalent condition, is typically preceded by disturbances in purine metabolism and is frequently associated with hyperlipidemia and other dysfunctions of metabolism. WN1703 demonstrated an inhibitory activity against xanthine oxidoreductase (XOR) that was comparable to febuxostat in our prior investigation. In this study, we assessed the cardiovascular safety of WN1703 in a chronic hyperuricemia rat model induced by potassium oxonate in combination with hypoxanthine. We investigated the changes in cardiovascular biomarkers in chronic hyperuricemia rats treated with febuxostat and WN1703, including creatine kinase (CK), CK-MB, B type natriuretic peptide (BNP), Corin protein (CRN), Neprilysin (NEP), myeloperoxidase (MPO), 8-hydroxy-2-deoxyguanosine (8-OHdG), tumor necrosis factor (TNF-α), interleukin-1β (IL-1β), and interleukin-8 (IL-8). Additionally, we validated the potential mechanism of cardiac injury induced by WN1703 in H9C2 cells, guided by cardiotoxicity predictions from the cardioToxCSM database and network pharmacology. We observed that excessively rapid urate-lowering, oxidative stress, and inflammation could disrupt myocardial functional homeostasis and increase the risk of cardiovascular injury in hyperuricemia rats, and WN1703 treatment effectively reduced the levels oxidative stress marker 8-OHdG and inflammatory factor TNF-α. Despite the absence of organic damage to the heart with prolonged treatment of febuxostat and WN1703, potential hazard of cardiovascular injury could be associated with the modulation of the TGFβ and RHO/ROCK signaling pathways by febuxostat and WN1703. This could offer new insights into the mechanisms underlying the adverse effects caused by XOR inhibitors.

Ocular Inflammation and Oxidative Stress as a Result of Chronic Intermittent Hypoxia: A Rat Model of Sleep Apnea.

Obstructive sleep apnea (OSA) is a sleep disorder characterized by intermittent complete or partial occlusion of the airway. Despite a recognized association between OSA and glaucoma, the nature of the underlying link remains unclear. In this study, we investigated whether mild OSA induces morphological, inflammatory, and metabolic changes in the retina resembling those seen in glaucoma using a rat model of OSA known as chronic intermittent hypoxia (CIH). Rats were randomly assigned to either normoxic or CIH groups. The CIH group was exposed to periodic hypoxia during its sleep phase with oxygen reduction from 21% to 10% and reoxygenation in 6 min cycles over 8 h/day. The eyes were subsequently enucleated, and then the retinas were evaluated for retinal ganglion cell number, oxidative stress, inflammatory markers, metabolic changes, and hypoxic response modulation using immunohistochemistry, multiplex assays, and capillary electrophoresis. Statistically significant differences were observed between normoxic and CIH groups for oxidative stress and inflammation, with CIH resulting in increased HIF-1α protein levels, higher oxidative stress marker 8-OHdG, and increased TNF-α. Pyruvate dehydrogenase kinase-1 protein was significantly reduced with CIH. No significant differences were found in retinal ganglion cell number. Our findings suggest that CIH induces oxidative stress, inflammation, and upregulation of HIF-1α in the retina, akin to early-stage glaucoma.

The effects of human amnion membrane-derived mesenchymal stem cells conditioned medium on ionizing radiation-induced premature ovarian failure and endoplasmic reticulum stress-related apoptosis mechanism

ObjectivesPremature ovarian failure (POF) is defined as the cessation of menstrual periods for at least 4–6 months before the age of 40 years, accompanied by FSH values measuring over 40 IU/L for a month. Radiation therapy, one of the cancer treatment methods, is known to accelerate ovarian aging by reducing and eliminating the number of primordial follicles in the ovarian follicle pool. Ionizing radiation has been reported to cause POF. The objective of this study is to investigate the impact of mesenchymal stem cell conditioned medium (hAMSCs-CM), which is isolated from the amniotic membrane of human placenta, on premature ovarian failure (POF) caused by whole-body irradiation. The study will focus on the ER stress and apoptosis mechanisms in the process. Study DisaynA POF model was created by exposing rats to 7 Gy of whole-body irradiation. Serum-free hAMSCs-CM were then administered via the tail vein. Follicle count was performed on the ovaries, and immunohistochemistry was used to determine the expressions of GRP78, CHOP, IRE-1, caspase-12, caspase-9, caspase-3. TUNEL was also carried out, and levels of serum FSH, LH, E2, AMH, and oxidative stress marker 8-OHdG were measured. Results and ConclusionThe application of hAMSCs-CM has been found to have a positive impact on follicles affected by radiation. After treatment, the number of primordial, primary, secondary, and graafian follicles, which had previously decreased due to radiation, showed an increase. Furthermore, the number of atretic follicles, which had been increasing due to radiation, showed a decrease. ER is one of the targets affected by ionizing radiation. After ionizing radiation, the expressions of ER stress-related markers and apoptosis markers increased in the ovary. After hAMSCs-CM administration, the expressions of these markers and number of TUNEL-positive cells decreased. Following irradiation, anti-mullerian hormone (AMH) and estradiol (E2) levels decreased, while follicle stimulating hormone (FSH) and luteinizing hormone (LH) levels increased. After administration of hAMSCs-CM, AMH and E2 levels increased, while FSH and LH levels decreased.Amnion membrane-derived mesenchymal stem cell conditioned medium can play a therapeutic role in ionizing radiation-induced premature ovarian failure by reducing endoplasmic reticulum stress and apoptosis.

Sestrin 3 promotes oxidative stress primarily in neurons following epileptic seizures in rats

Epilepsy affects approximately 1% of the global population, with 30% of patients experiencing uncontrolled seizures despite treatment. Reactive oxygen species (ROS) and oxidative stress have been implicated in the pathogenesis of epilepsy. Sestrins are stress-inducible proteins that regulate the ROS response. In particular, Sestrin 3 (SESN3) has been implicated in ROS accumulation and the regulation of proconvulsant genes. To investigate the role of SESN3 in epilepsy, we studied its involvement in rat models of acute seizures and temporal lobe epilepsy. Our results showed that downregulation of SESN3 reduced the oxidative stress induced by seizure activity in neuronal cultures. After acute seizure activity, SESN3 protein levels temporarily increased as early as 3 h after the seizure, whereas kainic acid-induced status epilepticus led to a significant and persistent increase in SESN3 protein levels in the cortex and hippocampus for up to 2 weeks post-status epilepticus. In the chronic epilepsy phase, when spontaneous seizures emerge, SESN3 protein expression is significantly increased in both regions 6 and 12 weeks after status epilepticus. Interestingly, immunohistochemical staining showed a predominant increase in the oxidative stress marker 8-OHdG in neurons in both regions after an acute seizure, whereas following status epilepticus, the marker was detected in both neurons and astrocytes. Our findings suggest that SESN3 may contribute to the development and establishment of epilepsy, and could be a potential therapeutic target for more effective treatments.

MP74-03 LONG-TERM ADMINISTRATION OF A PDE-5 INHIBITOR PREVENTS THE DEVELOPMENT OF BLADDER EPITHELIAL ATP INCREASE AND DECREASED DETRUSOR CONTRACTILITY IN TYPE 2 DIABETIC RATS

You have accessJournal of UrologyCME1 Apr 2023MP74-03 LONG-TERM ADMINISTRATION OF A PDE-5 INHIBITOR PREVENTS THE DEVELOPMENT OF BLADDER EPITHELIAL ATP INCREASE AND DECREASED DETRUSOR CONTRACTILITY IN TYPE 2 DIABETIC RATS Kabuto Takafumi, So Inamura, Hisato Kobayashi, Xinmin Zha, Keiko Nagase, Minekatsu Taga, Masaya Seki, Nobuki Tanaka, Yoshinaga Okumura, Osamu Yokoyama, and Naoki Tearada Kabuto TakafumiKabuto Takafumi More articles by this author , So InamuraSo Inamura More articles by this author , Hisato KobayashiHisato Kobayashi More articles by this author , Xinmin ZhaXinmin Zha More articles by this author , Keiko NagaseKeiko Nagase More articles by this author , Minekatsu TagaMinekatsu Taga More articles by this author , Masaya SekiMasaya Seki More articles by this author , Nobuki TanakaNobuki Tanaka More articles by this author , Yoshinaga OkumuraYoshinaga Okumura More articles by this author , Osamu YokoyamaOsamu Yokoyama More articles by this author , and Naoki TearadaNaoki Tearada More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003348.03AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: We examined a series of pathological conditions of bladder wall in a type 2 diabetes mellitus (T2DM) model (Otsuka Long-Evans Tokushima Fatty [OLEFT] rats) and evaluated the effects of a long-term administration of the PDE-5 inhibitor tadalafil (TA) on these conditions. METHODS: Male OLETF and Long-Evans Tokushima Otsuka (LETO) rats were used as T2DM and control groups, respectively. TA was orally administered for 12 weeks (wks) from the age of 36 wks. Bladder blood flow and ATP, prostaglandin E2 (PGE2), and nerve growth factor (NGF) released from the bladder epithelium were measured at 36 and 48 wks of age. Vesicular nucleotide transporter (VNUT), hypoxia-inducible factor-1 alpha (HIF-1α), 8-hydroxy-2′-deoxyguanosine (HIF-1α), the oxidative stress marker 8-OHdG, and the mRNA and protein of pro-inflammatory cytokines and growth factors in the bladder wall were measured by RT-PCRs and ELISAs. Bladder strip contractions to KCl and carbachol were monitored in the OLETF rat bladder. RESULTS: The bladder blood flow in the OLETF rats was decreased at 48 wks compared to 36 wks. TA increased the bladder blood flow. Epithelial ATP was significantly increased in OLETF compared to LETO and decreased by TA in both LETO and OLETF. The bladder VNUT expression was significantly elevated in OLETF versus LETO at 36 wks; it was further enhanced at 48 wks, but a significant decrease occurred with TA in both rat strains. HIF-1α and 8-OHdG of OLETF were upregulated at 48 wks and decreased by TA. In OLETF, the expressions of IL-6, IL-8, bFGF, TNF-α, TGF-β, IGF-1, and IGF1R were increased at 48 wks versus 36 wks. TA decreased IL-6, TNF-α, IGF-1 and IGF1R. In OLETF, the contractile response of bladder strips to KCl and carbachol decreased at 48 wks versus 36 wks, but it recovered after TA administration. CONCLUSIONS: These data suggest that impaired bladder blood flow resulted in increased expressions of HIF-1α, 8-OhdG, and various pro-inflammatory cytokines and growth factors In T2DM. As a result, the bladder epithelial ATP release was enhanced, possibly via VNUT upregulation. A long-term administration of a PDE-5 inhibitor could prevent the development of storage and voiding dysfunction associated with T2DM. This study is the first to suggest that epithelium-derived ATP may be involved in urine storage dysfunction in T2DM and tadalafil inhibits ATP release and improves bladder contraction. Source of Funding: None © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e1069 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Kabuto Takafumi More articles by this author So Inamura More articles by this author Hisato Kobayashi More articles by this author Xinmin Zha More articles by this author Keiko Nagase More articles by this author Minekatsu Taga More articles by this author Masaya Seki More articles by this author Nobuki Tanaka More articles by this author Yoshinaga Okumura More articles by this author Osamu Yokoyama More articles by this author Naoki Tearada More articles by this author Expand All Advertisement PDF downloadLoading ...

Biomarkers in patients with suspected obstructive sleep apnea and obstructive lung disease: Associations among polysomnographic, demographic and spirometric parameters

PURPOSE: The purpose of this study was to characterize the associations between inflammatory and oxidative stress biomarkers, demographic, polysomnographic and spirometric parameters in patients with suspected obstructive sleep apnea (OSA) and/or obstructive airway disease. METHODS: This was a cross-sectional exploratory study of patients referred to the University of British Columbia Sleep Clinic who had a diagnostic polysomnogram for suspected OSA. All patients had samples collected for measurements of IL-10, IL-6, e-selectin, endostatin, VCAM-1, ICAM-1, PDGF, thrombospondin-2, 8-OHdG, 8-isoprostane and superoxide dismutase. Spearman correlation and multiple linear regression were used to identify predictors of biomarkers. RESULTS: A total of 63 patients were included: 65% male, mean age 53 years and body mass index (BMI) 33 kg/m2. Inflammatory biomarkers were associated with female sex (IL-6, coefficient 0.51, p = 0.032), FEV1 (IL-6, coefficient −0.02, p = 0.013) and BMI (VCAM-1, coefficient 0.009, p = 0.051). The oxidative stress marker, 8-OHdG, was associated with hypoxemia in rapid eye movement (REM) sleep (coefficient 0.006, p = 0.02). Age and BMI were both independently associated with percentage of time spent below SpO2 90%. REM sleep and patients with overlap conditions and OSA had greater degree of REM and nonrapid eye movement (NREM) sleep hypoxemia than control group. Lastly, there were no differences in oxidative or inflammatory biomarkers between control, OSA, obstructive airway disease and overlap groups though the number of patients in each group were small. CONCLUSION: Female sex, lower FEV1 and increased BMI were independent predictors of increased inflammatory biomarker levels. The oxidative stress marker 8-OHdG was associated with hypoxemia indices of REM. Larger studies are warranted to delineate biomarker profiles in patients with overlap conditions.

Pain Modulation from the Locus Coeruleus in a Model of Hydrocephalus: Searching for Oxidative Stress-Induced Noradrenergic Neuroprotection.

Pain transmission at the spinal cord is modulated by noradrenaline (NA)-mediated actions that arise from supraspinal areas. We studied the locus coeruleus (LC) to evaluate the expression of the cathecolamine-synthetizing enzyme tyrosine hydroxylase (TH) and search for local oxidative stress and possible consequences in descending pain modulation in a model of hydrocephalus, a disease characterized by enlargement of the cerebral ventricular system usually due to the obstruction of cerebrospinal fluid flow. Four weeks after kaolin injection into the cisterna magna, immunodetection of the catecholamine-synthetizing enzymes TH and dopamine-β-hydroxylase (DBH) was performed in the LC and spinal cord. Colocalization of the oxidative stress marker 8-OHdG (8-hydroxyguanosine; 8-OHdG), with TH in the LC was performed. Formalin was injected in the hindpaw both for behavioral nociceptive evaluation and the immunodetection of Fos expression in the spinal cord. Hydrocephalic rats presented with a higher expression of TH at the LC, of TH and DBH at the spinal dorsal horn along with decreased nociceptive behavioral responses in the second (inflammatory) phase of the formalin test, and formalin-evoked Fos expression at the spinal dorsal horn. The expression of 8-OHdG was increased in the LC neurons, with higher co-localization in TH-immunoreactive neurons. Collectively, the results indicate increased noradrenergic expression at the LC during hydrocephalus. The strong oxidative stress damage at the LC neurons may lead to local neuroprotective-mediated increases in NA levels. The increased expression of catecholamine-synthetizing enzymes along with the decreased nociception-induced neuronal activation of dorsal horn neurons and behavioral pain signs may indicate that hydrocephalus is associated with alterations in descending pain modulation.

Testis‐Specific Thioredoxins TXNDC2, TXNDC3, and TXNDC6 Are Expressed in Both Testicular and Systemic DLBCL and Correlate with Clinical Disease Presentation

DLBCL is the most common type of non-Hodgkin lymphoma with a substantial group of patients suffering a poor prognosis. Therefore more specific markers are required for better understanding of disease biology and treatment. This study demonstrates that testis-specific antioxidant enzymes TXNDC2, TXNDC3, and TXNDC6 alongside oxidative stress marker 8-OHdG are expressed in both testicular and systemic DLBCL, and their presence or absence has correlations with clinical risk factors such as the number of extranodal effusion, the appearance of B-symptoms, and treatment response. Biopsy samples were collected from 28 systemic and 21 testicular male DLBCL patients. The samples were histostained with TXNDC2, TXNDC3, TXNDC6, and 8-OHdG, then graded by a hematopathologist blinded to clinical data. Immunoelectron microscopy was used as a second method to confirm the reliability of the acquired immunohistochemistry data. The absence of nuclear TXNDC2 expression in testicular DLBCL cells correlated with worse primary treatment response, cytoplasmic TXNDC3 expression in testicular and systemic DLBCL associated with lower frequency of B-symptoms, and TXNDC6 expression in cytoplasm in systemic DLBCL had a clinical significance with higher LD levels suggesting a role in the biological nature of these lymphomas. Overall, TXNDC3 cytoplasmic expression is correlated with a more positive outcome in both testicular and systemic DLBCL, while TXNDC6 cytoplasmic expression is associated with a negative outcome in systemic DLBCL.

Effects of Connexin 32-Mediated Lung Inflammation Resolution During Liver Ischemia Reperfusion.

Hepatic ischemia reperfusion (HIR) leads to a lung inflammatory response and subsequent pulmonary barrier dysfunction. The gap junction communication protein connexin 32 (Cx32), which is widely expressed in the lungs, participates in intercellular signaling. This study determined whether the communication protein Cx32 could affect pulmonary inflammation caused by HIR. Mice were randomly allocated into four groups (n = 8/group): (i) Cx32+/+ sham group; (ii) Cx32+/+ HIR model group; (iii) Cx32-/- sham group; and (iv) Cx32-/- HIR model group. Twenty-four hours after surgery, lung tissues were collected for bright field microscopy, western blot (Cx32, JAK2, p-JAK2, STAT3, p-STAT3), and immunofluorescence (ZO-1, 8-OHDG) analyses. The collected bronchoalveolar fluid was tested for levels of interleukin-6 (IL-6), matrix metalloproteinase 12 (MMP-12), and antitrypsin (α1-AT). Lung mmu-miR-26a/b expression was detected using a PCR assay. Increased expression of Cx32 mRNA and protein was noted in the lungs after HIR. Cx32 deletion significantly aggravated pulmonary function from acute lung injury induced by HIR. In addition, Cx32 deletion decreased the protein level of ZO-1 (pulmonary function) and increased the level of the oxidative stress marker 8-OHDG in the lungs. Moreover, in the Cx32-/- HIR model group, the levels of IL-6 and MMP-12 in bronchoalveolar lavage fluid were significantly increased leading to activation of the JAK2/STAT3 pathway, and decreased α1-AT levels. Furthermore, we found mmu-miR-26a/b was significantly downregulated in the Cx32-/- HIR model group. HIR leads to acute lung inflammatory injury. Cx32 deletion aggravates hepatic-derived lung inflammation, partly through blocking the transferring of mmu-miR-26a/b and leading to IL-6-related JAK2/STAT3 pathway activation.

Orthodontic force-induced oxidative stress in the periodontal tissue and dental pulp elicits nociception via activation/sensitization of TRPA1 on nociceptive fibers

Orthodontic patients complain of pain for the first few days after insertion of appliances. Mechanical force has been reported to produce oxidants in periodontal ligament (PDL) cells. It has not been studied whether orthodontic force-induced oxidative stress elicits nociception. Herein, we focused on the role of the oxidant-sensitive channel TRPA1 on nociception in orthodontic pain. In a rat model of loaded orthodontic force between the maxillary first molar and incisor, the behavioral signs of orofacial nociception, facial rubbing and wiping, increased to a peak on day 1 and gradually diminished to the control level on day 5. Administration of free radical scavengers (Tempol and PBN) and TRPA1 antagonist (HC-030031) inhibited nociceptive behaviors on day 1. In the PDL, the oxidative stress marker 8-OHdG was highly detected on day 1 and recovered on day 5 to the sham-operated level. The dental pulp showed similar results as the PDL. TRPA1 mRNA was abundantly expressed in the trigeminal ganglion relative to PDL tissue, and there were TRPA1-immunopositive neuronal fibers in the PDL and pulp. In dissociated trigeminal ganglion neurons, H2O2 at 5 mM induced a Ca2+ response that was inhibited by HC-030031. Although H2O2 at 100 μM did not yield any response, it enhanced the mechanically activated TRPA1-dependent Ca2+ response. These results suggest that oxidative stress in the PDL and dental pulp following orthodontic force activates and/or mechanically sensitizes TRPA1 on nociceptive fibers, resulting in orthodontic nociception. Later, the disappearance of nociception seems to be related to a decrease in oxidative stress, probably due to tissue remodeling.

Fibroblast growth factor 23 does not directly influence skeletal muscle cell proliferation and differentiation or ex vivo muscle contractility.

Skeletal muscle dysfunction accompanies the clinical disorders of chronic kidney disease (CKD) and hereditary hypophosphatemic rickets. In both disorders, fibroblast growth factor 23 (FGF23), a bone-derived hormone regulating phosphate and vitamin D metabolism, becomes chronically elevated. FGF23 has been shown to play a direct role in cardiac muscle dysfunction; however, it is unknown whether FGF23 signaling can also directly induce skeletal muscle dysfunction. We found expression of potential FGF23 receptors ( Fgfr1-4) and α-Klotho in muscles of two animal models (CD-1 and Cy/+ rat, a naturally occurring rat model of chronic kidney disease-mineral bone disorder) as well as C2C12 myoblasts and myotubes. C2C12 proliferation, myogenic gene expression, oxidative stress marker 8-OHdG, intracellular Ca2+ ([Ca2+]i), and ex vivo contractility of extensor digitorum longus (EDL) or soleus muscles were assessed after treatment with various amounts of FGF23. FGF23 (2-100 ng/ml) did not alter C2C12 proliferation, expression of myogenic genes, or oxidative stress after 24- to 72-h treatment. Acute or prolonged FGF23 treatment up to 6 days did not alter C2C12 [Ca2+]i handling, nor did acute treatment with FGF23 (9-100 ng/ml) affect EDL and soleus muscle contractility. In conclusion, although skeletal muscles express the receptors involved in FGF23-mediated signaling, in vitro FGF23 treatments failed to directly alter skeletal muscle development or function under the conditions tested. We hypothesize that other endogenous substances may be required to act in concert with FGF23 or apart from FGF23 to promote muscle dysfunction in hereditary hypophosphatemic rickets and CKD.

Oxidative stress and repetitive element methylation changes in artisanal gold miners occupationally exposed to mercury.

Mercury (Hg) exposure is a public health concern due to its persistence in the environment and its high toxicity. Such toxicity has been associated with the generation of oxidative stress in occupationally exposed subjects, such as artisanal gold miners. In this study, we characterize occupational exposure to Hg by measuring blood, urine and hair levels, and investigate oxidative stress and DNA methylation associated with gold mining. To do this, samples from 53 miners and 36 controls were assessed. We show higher levels of oxidative stress marker 8-OHdG in the miners. Differences in LINE1 and Alu(Yb8) DNA methylation between gold miners and control group are present in peripheral blood leukocytes. LINE1 methylation is positively correlated with 8-OHdG levels, while XRCC1 and LINE1 methylation are positively correlated with Hg levels. These results suggest an effect of Hg on oxidative stress and DNA methylation in gold miners that may have an impact on miners’ health.

Polycyclic aromatic hydrocarbons exposure, oxidative stress, and asthma in children.

Polycyclic aromatic hydrocarbons (PAHs) are known for their carcinogenic and teratogenic properties. However, little is known about the effect of PAH on our immune and respiratory systems. Hence, we investigated associations (1) between PAH exposure and IgE levels and asthma in children and (2) between PAH exposure and the oxidative stress marker 8OHdG potentially involved in disease pathogenesis stratifying by (3) sex-based differences. A total of 453 kindergarten children were recruited and provided samples. Urine biomarker of PAH exposure (1-OHP levels) was measured by UPLC-MS/MS and a marker of oxidative stress (8OHdG) was measured by ELISA. Serum IgE were assessed and information on asthma was collected. Associations between 1-OHP levels, 8OHdG, IgE and asthma were analyzed by multivariate linear and logistic regression. A mediation analysis was conducted to evaluate whether the risk of increased IgE and asthma related to PAH exposure is explained by 8OHdG changes. Urine 1-OHP levels were positively related to 8OHdG levels (per ln-unit: β = 0.30kU/l, p = 0.002). Similar results were also found for 1-OHP levels with IgE levels (per ln-unit: β = 0.27 kU/l, p = 0.027). 1-OHP levels (per ln-unit) were significantly associated with asthma, with an OR (95% CI) of 1.42 (1.18-1.70). In addition, 1-OHP levels were associated with asthma. It is estimated that 35% of the effect of PAH exposure on asthma is mediated by 8OHdG levels. Exposure to PAH may enhance oxidative stress and may induce asthma. The effect of PAH exposure on asthma may be mediated by oxidative stress.

Assessment of genotoxicity of pyrethrin in cultured human lymphocytes

Pyrethrin is an insecticide that is obtained from the Chrysanthemum flower (Pyrethrum). In this study, we examined the genotoxic effects of pyrethrin on cultured human lymphocytes using sister chromatid exchanges (SCEs) and 8-hydroxy deoxyguanosine (8-OHdG) assays. Cultures were treated with different concentrations of pyrethrin (25, 50, and 100 μg/mL), which was dissolved in in dimethyl sulfoxide (DMSO). The results showed that treatment of cultured lymphocytes with pyrethrin at 50 μg/mL and 100 μg/mL induced significant elevation in SCEs (p < 0.05). In addition, the 100 μg/mL concentration significantly affected both mitotic and proliferative indices (p < 0.05). Finally, pyrethrin induced significant elevation in the oxidative stress marker 8-OHdG in a dose-dependent manner (p < 0.001). In conclusion, the results suggest that pyrethrin is genotoxic as measured by two independent assays on genetic toxicity.

The plasma 8-OHdG levels and oxidative stress following cholecystectomy: a randomised multicentre study of patients with minilaparotomy cholecystectomy versus laparoscopic cholecystectomy

Objective: The aim of the study was to evaluate the role of 8-OHdG (8-hydroxy-2′-deoxyguanosine) detecting oxidative stress response following cholecystectomy in a randomised multicentre study of patients with minilaparotomy cholecystectomy (MC) versus laparoscopic cholecystectomy (LC).Methods: Initially, 106 patients with non-complicated symptomatic gallstone disease were randomised into MC (n = 56) or LC (n = 50) groups. Plasma levels of the oxidative stress marker 8-OHdG measured at three time points; before (PRE), immediately after (POP1) and 6 h after operation (POP2).Results: The demographic variables and the surgical data were similar in the study groups. The plasma oxidative stress marker 8-OHdG concentrations following surgery in the MC versus LC patients were quite similar. There was no significant correlation between the individual values of the11-point numeric rating pain scale (NRS) versus the plasma 8-OHdG post-operatively in the MC and LC patients. However, there was a statistically significant correlation between the individual values of the plasma 8-OHdG (PRE) versus IL-10 (PRE) for the MC and LC patients (r = 0.214, p = 0.037). There was also a statistically significant correlation between the individual values of the plasma 8-OHdG (POP2) versus IL-1β (POP2) for the MC and LC patients (r = 0.25, p = 0.01).Conclusion: Our results suggest that the oxidative stress marker 8-OHdG concentrations following surgery in MC versus LC patients were quite similar. A new finding with possible clinical relevance is a correlation between the individual plasma values of the 8-OHdG versus anti-inflammatory interleukin IL-10 and 8-OHdG versus IL-1β (proinflammatory) in the MC and LC patients suggesting that inflammation and oxidative stress are related.

Remote Ischemic Preconditioning Reduces Cerebral Oxidative Stress Following Hypothermic Circulatory Arrest in a Porcine Model

Remote ischemic precondition has become prominent as one of the most promising methods to mitigate neurological damage following ischemic insult. The purpose of this study was to investigate whether the effects of remote ischemic preconditioning can be seen in the markers of oxidative stress or in redox-regulating enzymes in a porcine model. A total of 12 female piglets were randomly assigned to 2 groups. The study group underwent an intervention of 4 cycles of 5-minute ischemic preconditioning on the right hind leg. All piglets underwent 60-minute hypothermic circulatory arrest. Oxidative stress marker 8-hydroxydeoxyguanosine (8-OHdG) was measured from blood samples with enzyme-linked immunosorbent assay. After 7 days of follow-up, samples from the brain, heart, kidney, and ovary were harvested for histopathologic examination. The immunohistochemical stainings of hypoxia marker hypoxia-inducible factor-1-α, oxidative stress marker 8-OHdG, DNA repair enzyme 8-oxoguanine glycosylase, and antioxidant response regulators nuclear factor erythroid 2-related factor 2 and protein deglycase were analyzed. The level of 8-OHdG referred to baseline was decreased in the sagittal sinus׳ blood samples in the study group after a prolonged deep hypothermic circulatory arrest at 360 minutes after reperfusion. Total histopathologic score was 3.8 (1.8-6.0) in the study group and was 4.4 (2.5-6.5) in the control group (P = 0.72), demonstrating no statistically significant difference in cerebral injury. Our findings demonstrate that the positive effects of remote ischemic preconditioning can be seen in cellular oxidative balance regulators in an animal model after 7 days of preconditioned ischemic insult.

1,4-benzoquinone-induced STAT-3 hypomethylation in AHH-1 cells: Role of oxidative stress

Benzene, a known occupational and environmental contaminant, is associated with increased risk of leukemia. The objectives of this study were to elucidate the regulatory mechanism of the hypomethylated STAT3 involved in benzene toxicity in vitro. As 1,4-benzoquinone (1,4-BQ) is one of benzene’s major toxic metabolites, AHH-1 cells were treated by 1,4-BQ for 24h with or without pretreatment of the antioxidant a-LA or the methyltransferase inhibitor, 5-aza-2′ deoxycytidine (5-aza). The cell viability was investigated using the 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. ROS was determined via 2′,7′-dichlorodihydrofluorescein diacetate (DCFDA) flow cytometric assays. The level of oxidative stress marker 8-OHdG was measured by enzyme-linked immunosorbent assay. Methylation-specific PCR was used to detect the methylation status of STAT3. Results indicated the significantly increasing expression of ROS and 8-OHdG which accompanied with STAT3 hypomethylation in 1,4-BQ-treated AHH-1 cells. α-LA suppressed the expression of both ROS and 8-OHdG, simultaneously reversed 1,4-BQ-induced STAT3 hypomethylation. However, although the methylation inhibitor, 5-aza reduced the expression level of ROS and 8-OHdG, but had no obvious inhibiting effect on STAT3 methylation level. Taken together, oxidative stress are involved 1,4-BQ-induced STAT3 methylation expression.

Rapid and intermediate N-acetylators are less susceptible to oxidative damage among 4,4′-methylenebis(2-chloroaniline) (MBOCA)-exposed workers

In this study, we explored the association between a marker of oxidative stress, 8-hydroxydeoxyguanosine (8-OHdG), and genetic polymorphism of the carcinogen-metabolizing enzyme N-acetyltransferase 2 (NAT2) among 4,4'-methylenebis(2-chloroaniline) (MBOCA)-exposed workers. The study population was recruited from four MBOCA-producing factories, and included 57 MBOCA-exposed workers and 101 unexposed control workers. Personal characteristics were collected by questionnaire. Plasma 8-OHdG levels were measured by LC/MS/MS. NAT2 alleles were measured by polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP). NAT2 polymorphism influenced the plasma 8-OHdG levels of MBOCA-exposed workers, but not of non-exposed workers. No difference between exposed and control groups was found for the crude 8-OHdG levels among rapid, intermediate, and slow acetylators. After adjusting for gender, age, smoking, and alcohol consumption habit, the 8-OHdG concentration in the MBOCA-exposed workers was 0.18pg/ml (95% CI -1.80 to -0.12) lower than the control group among rapid and intermediate acetylators. However, the difference between exposed and control groups was not significant for slow acetylators. Gene-environment interactions could play a role in the carcinogenesis of occupational MBOCA exposure. We suggest that the impact of the NAT2 acetylator status is low, if at all, on the generation of the oxidative stress marker 8-OHdG in the investigated exposed group.

Effect of mitochondrial transcription factor a overexpression on motor neurons in amyotrophic lateral sclerosis model mice

Increasing evidence indicates that oxidative stress is an important mechanism underlying motor neuron (MN) degeneration in amyotrophic lateral sclerosis (ALS). Mitochondrial DNA (mtDNA) is highly susceptible to oxidative damage and has little potential for repair, although mitochondrial transcription factor A (TFAM) plays essential roles in maintaining mitochondrial DNA by reducing oxidative stress, promoting mtDNA transcription, and regulating mtDNA copy number. To analyze a possible therapeutic effect of TFAM on ALS pathology, double transgenic mice overexpressing G93A mutant SOD1 (G93ASOD1) and human TFAM (hTFAM) were newly generated in the present study. Rotarod scores were better in G93ASOD1/hTFAM double-Tg mice than G93ASOD1 single-Tg mice at an early symptomatic stage, 15 and 16 weeks of age, with a 10% extension of the onset age in double-Tg mice. The number of surviving MNs was 30% greater in double-Tg mice with end-stage disease, at 19 weeks, with remarkable reductions in the amount of the oxidative stress marker 8-OHdG and the apoptotic marker cleaved caspase 3 and with preserved COX1 expression. Double-immunofluorescence study showed that hTFAM was expressed specifically in MNs and microglia in the spinal cords of double-Tg mice. The present study suggests that overexpression of TFAM has a potential to reduce oxidative stress in MN and delay onset of the disease in ALS model mice. © 2012 Wiley Priodicals, Inc.

The metabolisms of agaritine, a mushroom hydrazine in mice

The mushroom hydrazine agaritine was measured in mouse plasma and urine using LC/MS/MS, which is highly specific. Agaritine concentration peaked 20 min after oral administration to mice (4.0 and 40 mg/kg). The concentration gradually decreased and returned to the basal level in 100 min. The maximum concentration, the time to the maximum concentration, and the half life were 0.37 μg/ml plasma, 0.33 h, and 0.71 h, respectively after administration of agaritine at 40 mg/kg body weight. One agaritine metabolite was found in the plasma and the urine from agaritine-administered mice. The structure of metabolites of agaritine by γ-GT was next investigated using LC/MS. HMPH proved to be generated from agaritine. The oxidative stress marker 8-OHdG was detected in agaritine-administered mouse urine. After administration, the 8-OHdG level immediately tripled, and then decreased to the control level over 48 h. Its level then elevated again and remained high for 11 days. These results suggest that agaritine quickly metabolizes and disappears in the plasma, whereas DNA damage lasts for a long time after a single administration of agaritine to mice.