DNA Damage In Leukocytes Research Articles

Assessment of DNA Damage in Leukocytes of Patients With Coronary Artery Disease by Comet Assay.

DNA damage in the peripheral blood leukocytes (PBL) of patients with coronary artery disease (CAD) was investigated using the sensitive alkaline single cell gel electrophoresis (SCGE)/comet assay.This case-control study consisted of CAD patients (n = 200; mean age, 59.04 ± 0.75 years) undergoing treatment at local hospitals and age-, sex-, and ethnicity-matched healthy controls (n = 200; mean age, 57.88 ± 0.96 years) from the general population.CAD patients had significantly (P < 0.001) increased DNA damage (tail DNA percent (T-DNA %) 22.45 ± 0.50 versus 5.81 ± 0.28; tail moment (TM) 89.35 ± 3.16 versus 9.98 ± 0.69; Olive tail moment (OTM) 60.50 ± 1.79 versus 10.94 ± 0.63; damage frequency (DF) 91.12 ± 0.93 versus 41.78 ± 2.04, damage index (DI) 173.68 ± 3.36 versus 48.53 ± 2.59) compared to controls. Patients with acute myocardial infarction (AMI) showed significantly higher DNA damage than patients with unstable angina (UA) (T-DNA % 24.05 ± 0.87 versus 21.06 ± 0.90; TM 100.02 ± 6.19 versus 81.61 ± 5.84; OTM 66.19 ± 3.20 versus 56.47 ± 3.33; DF 94.02 ± 0.84 versus 91.10 ± 1.16, DI 184.13 ± 5.33 versus 166.42 ± 5.89). Moreover, DNA damage was found to be significantly (P < 0.05) elevated in patients receiving ecosprin, ramipril, and metoprolol therapy compared to aspirin and nitrocontin.The increased DNA damage in CAD patients may be the consequence of disease and/or drug therapy. These observations are of concern because unrepaired DNA can lead to malignancy, and the likelihood of increasing mortality and morbidity rates in CAD patients.

Oxidative DNA damage and oxidative stress in lead-exposed workers.

There are many discrepancies among the results of studies on the genotoxicity of lead. The aim of the study was to explore lead-induced DNA damage, including oxidative damage, in relation to oxidative stress intensity parameters and the antioxidant defense system in human leukocytes. The study population consisted of 100 male workers exposed to lead. According to the blood lead (PbB) levels, they were divided into the following three subgroups: a group with PbB of 20-35 μg/dL (low exposure to lead (LE) group), a group with a PbB of 35-50 µg/dL (medium exposure to lead (ME) group), and a group with a PbB of >50 μg/dL (high exposure to lead (HE) group). The control group consisted of 42 healthy males environmentally exposed to lead (PbB < 10 μg/dL). A comet assay was used to measure the DNA damage in leukocytes. We measured the activity of superoxide dismutase (SOD), catalase, glutathione reductase (GR), glucose-6-phosphate dehydrogenase (G6PD), and glutathione-S-transferase (GST) as well as the concentration of malondialdehyde (MDA), and the value of the total antioxidant capacity. The level of PbB was significantly higher in the examined subgroups than in the control group. The percentage of DNA in the tail was significantly higher in the LE, ME, and HE subgroups than in the control group by 10% ( p = 0.001), 15% ( p < 0.001), and 20% ( p < 0.001), respectively. The activity of GR was significantly lower in the LE and ME subgroups than in the control group by 25% ( p = 0.007) and 17% ( p = 0.028), respectively. The activity of G6PD was significantly lower in the ME subgroup by 25% ( p = 0.022), whereas the activity of GST was significantly higher in the HE subgroup by 101% ( p = 0.001) than in the control group. Similarly, the activity of SOD was significantly higher in the LE and ME subgroups by 48% ( p = 0.026) and 34% ( p = 0.002), respectively. The concentration of MDA was significantly higher in the LE, ME, and HE subgroups than in the control group by 43% ( p = 0.016), 57% ( p < 0.001), and 108% ( p < 0.001), respectively. Occupational lead exposure induces DNA damage, including oxidative damage, in human leukocytes. The increase in DNA damage was accompanied by an elevated intensity of oxidative stress.

Oleuropein Prevents Azoxymethane-Induced Colon Crypt Dysplasia and Leukocytes DNA Damage in A/J Mice.

Previous studies have shown that the precursor of olive oil secoiridoids, Oleuropein (OL) has several in vitro chemopreventive properties. OL inhibits proliferation and induces apoptosis in breast, thyroid, prostate, and colorectal cancer (CRC) cells. Much less is known about the effects of OL on animal models of carcinogenesis. In this study, we investigated the ability of OL to prevent the azoxymethane (AOM)-induced colon cancer upset and DNA damage in mice. Animals, fed with a basal diet either enriched or not with OL (125 mg/kg), were injected with AOM (10 mg/kg, once a week for 6 weeks) and sacrificed after either 7 weeks for histological analysis of colon crypt dysplasia and evaluation of DNA damage in leukocytes or 17 weeks for counting the macroscopically observable colon tumors. An OL-enriched diet prevented the AOM-induced preneoplastic lesions in different colon segments, reducing the severity of crypt dysplasia and DNA damage in peripheral leukocytes. In addition, OL significantly reduced the AOM-induced tumor incidence from 57% to 14% (P < .05, chi-square test) in the medial colon segment. This study shows that OL is able to prevent CRC and DNA damage in mice treated with the carcinogen AOM. These results stimulate further human cancer prevention studies with OL-enriched food supplements that are actually available on the market.

Effect of in vivo and in vitro exposure to electrostatic field on some hematological parameters in rats.

The aim of this study was to investigate the effect of the external electrostatic field (ESF) on some hematological parameters in rats. Both in vivo and in vitro experiments were carried out. In in vivo investigations, rats were exposed to ESF (200 kV/m) during short (1 h) and long periods (6 days, 6 h daily). For in vitro study, the blood of intact rats was exposed to ESF for 1 h. Blood hematology was measured using validated ABX Micros ESV 60 Veterinary Hematology Analyzer. DNA damage in blood leucocytes was detected by means of comet assay. ESF effect on blood cell count was mainly manifested in white blood cells (WBC) and platelets. Damage of WBC was shown both in vitro and in vivo despite alterations in the count. This means the observed increase in WBC count in some cases might be a result of WBC compensatory mobilization from the bone marrow. Red blood cell (RBC) count and related parameters were slightly affected by ESF. Nevertheless, alterations in the shape and size of RBC were manifested. All ESF effects were extinguished in 14 days after the end of exposure. Bioelectromagnetics. 37:513-526, 2016. © 2016 Wiley Periodicals, Inc.

Dihydroxyselenolane (DHS) supplementation improves survival following whole-body irradiation (WBI) by suppressing tissue-specific inflammatory responses

Dihydroxyselenolane (DHS), a simple water-soluble organoselenium compound, was evaluated for radioprotection in BALB/c mice after whole-body irradiation (WBI) (8Gy 60Co, 1Gy/min), by monitoring 30-d post-irradiation survival and biochemical/histological changes in radiosensitive organs. Intraperitoneal administration of DHS at 2mg/kg for five consecutive days before irradiation and three times per week during the post-irradiation period showed maximum benefit (40% improvement in 30 d post-irradiation survival). DHS treatment, despite inducing expression of glutathione peroxidases (GPx1, GPx2, and GPx4) in spleen and intestine, did not protect against radiation-induced acute (10-day) haematopoietic and gastrointestinal toxicities. DHS treatment significantly reduced radiation-induced DNA damage in peripheral leukocytes and inflammatory responses in intestine, lung, and circulation. The anti-inflammatory effect of DHS was associated with reductions in lipid peroxidation, expression of pro-inflammatory genes such as Icam-1, Ccl-2, and iNos-2, and subsequent infiltration of inflammatory cells. Irradiated mice treated with DHS survived until day 30 post-irradiation and showed restoration of spleen cellularity and intestinal villi, but had moderately increased systemic and tissue-specific inflammatory responses. Another organoselenium compound, selenomethionine, evaluated in parallel with DHS at the same dose and treatment schedule, showed comparable radioprotective effects. The mechanism of radioprotection by DHS is mainly via suppression of inflammatory responses.

Antioxidant, genoprotective and immunomodulatory potential of Vitex negundo leaves in experimental arthritis

Vitex negundo is a medicinal plant used in Indian and folklore medicines to cure various ailments including arthritis. In the present study, the hydroethanolic extract of V. negundo leaves (VNE) were evaluated for antioxidant, genoprotective and immunomodulatory activity in Freund’s complete adjuvant (FCA) induced arthritis. VNE was evaluated for in vitro antioxidant activity using various parameters including plasmid nicking assay. VNE (200 mg/kg body weight) was orally administered to FCA induced arthritic rats to evaluate its genoprotective effects on peripheral blood leukocytes using the alkaline comet assay. Furthermore, the effects of VNE treatment on serum proinflammatory mediators such as tumor necrosis factor-α (TNF-α) and interleukin -1α (IL-1α) and the hematological parameters such as total RBC count, hematocrit and hemoglobin were measured in arthritic rats. The results showed that VNE exhibited potential in vitro antioxidant and DNA protecting activities in a concentration dependent manner. The phytoconstituents of VNE showed a strong and positive correlation with the antioxidant properties. DNA damage in the peripheral blood leukocytes of arthritic animals was significantly decreased after VNE treatment. VNE showed inhibition of serum proinflammatory cytokines (TNF-α and IL-1α) however, the inhibition was statistically not-significant. The arthritic animals showed significant increase in hemolysis, which was restored by VNE treatment. The results of the present study indicate that VNE may be a source of antioxidant, genoprotective with immunomodulatory activity, which may be attributed to its antioxidant phytoconstituents.

Genotoxic Effect of Methotrexate on Bone Marrow Chromosomes and DNA of Male Albino Mice (Mus Musculus)

Aim of the work-Methotrexate (MTX), a structural analogue of folic acid, is an antineoplastic and antirheumatic agent which is used in a variety of clinical schedules and combination therapy regimens in man. Material and methods- Sixty mice of nearly the same age were randomly categorized into four groups (one control and three treated groups with different doses of methotrexate). Mice of the treated groups 1, 2 and 3 were intraperitoneally injected with a single dose of methotrexate (2.5, 5 or 10 mg/kg b. wt. respectively) at the first day of the experiment. All the control and the treated animals were sacrificed after 24, 48 or 72 hour by cervical dislocation post treatment. Results-Methotrexate treatment induced structural and numerical chromosomal aberrations in male mice bone marrow cells which were significantly increased (P< 0.001) by dose and time. Structural aberrations were chromosomal gap, fragment, break, centromeric attenuation, deletion, centric fusion, ring formation, end to end association and beaded chromosomes. Numerical aberration was polyploidy. Also, methotrexate treatment decreased the mitotic index in bone marrow cells of all the treated mice in comparison with the control group by increasing dose and time of treatment. Comet assay results indicated that treatment with methotrexate significantly increased (P< 0.001) DNA damage in the blood leukocytes in dose and time dependent manner. Conclusion- It can be concluded that methotrexate induced genetic damage on the chromosomes and DNA content of male albino mice even after single treatment with low doses.

Safety and feasibility of fasting in combination with platinum-based chemotherapy.

BackgroundShort-term starvation prior to chemotherapy administration protects mice against toxicity. We undertook dose-escalation of fasting prior to platinum-based chemotherapy to determine safety and feasibility in cancer patients.Methods3 cohorts fasted before chemotherapy for 24, 48 and 72 h (divided as 48 pre-chemo and 24 post-chemo) and recorded all calories consumed. Feasibility was defined as ≥ 3/6 subjects in each cohort consuming ≤ 200 kcal per 24 h during the fast period without excess toxicity. Oxidative stress was evaluated in leukocytes using the COMET assay. Insulin, glucose, ketones, insulin-like growth factor-1 (IGF-1) and IGF binding proteins (IGFBPs) were measured as biomarkers of the fasting state.ResultsThe median age of our 20 subjects was 61, and 85 % were women. Feasibility criteria were met. Fasting-related toxicities were limited to ≤ grade 2, most commonly fatigue, headache, and dizziness. The COMET assay indicated reduced DNA damage in leukocytes from subjects who fasted for ≥48 h (p = 0.08). There was a non-significant trend toward less grade 3 or 4 neutropenia in the 48 and 72 h cohorts compared to 24 h cohort (p = 0.17). IGF-1 levels decreased by 30, 33 and 8 % in the 24, 48 and 72 h fasting cohorts respectively after the first fasting period.ConclusionFasting for 72 h around chemotherapy administration is safe and feasible for cancer patients. Biomarkers such as IGF-1 may facilitate assessment of differences in chemotherapy toxicity in subgroups achieving the physiologic fasting state. An onging randomized trial is studying the effect of 72 h of fasting.Trial registrationNCT00936364, registered propectively on July 9, 2009.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-016-2370-6) contains supplementary material, which is available to authorized users.

Pulmonary Functions, Oxidative Stress and DNA Damage in Workers of a Copper Processing Industry.

Background:Occupational exposure to excessive level of copper results in many adverse health effects.Objective:To measure pulmonary function, oxidative stress, and extent of DNA damage in workers of a copper processing industry.Methods:30 men working in a copper processing industry and 30 men matched for age and socioeconomic status (comparison group) were included in this study. Pulmonary function test parameters were measured for all participants. Serum malondialdehyde (MDA), ferric reducing ability of plasma (FRAP), glutathione (GSH) content in RBCs and 8-OHdG were assayed by ELISA. Extent of DNA damage in leucocytes was assayed by comet assay.Results:Pulmonary function parameters, FVC, FEV1, PEFR, and MVV measured in workers were significantly (p<0.05) lower than those observed in the comparison group. Compared to the comparison group, MDA was significantly (p=0.002) increased in studied workers; TAOC (p=0.017), and GSH (p=0.020) were significantly lower in workers than the comparison group. There was significant DNA damage in leucocytes in workers compared to the comparison group (difference in olive tail moment p<0.001). PEFR, FEF25-75%, and MEF50% were negatively correlated with MDA.Conclusion:The observed DNA damage would be due to increased oxidative stress resulting from excessive exposure to copper.

Changes of oxidative/antioxidative parameters and DNA damage in firefighters wearing personal protective equipment during treadmill walking training.

[Purpose] The purpose of this study was to investigate the influence of personal protective equipment on the oxidant/antioxidant parameters and DNA damage in firefighters during training and recovery. [Subjects and Methods] Twelve male nonsmoking volunteer firefighters (35.1 ± 7.2 years) underwent two maximal treadmill training (9 METs, 6 km/h), within 2 weeks, one in regular clothes and one in personal protective equipment weighing 22.1 kg. Blood samples were obtained before, right after, and 40 min after training. Plasma conjugated dienes, total radical trapping antioxidant potential, erythrocytes antioxidant enzymes activities, and leukocyte DNA damage were measured. [Results] Wearing personal protective equipment during treadmill walking training resulted in increases of plasma conjugated dienes, total radical trapping antioxidant potential, and leukocyte DNA resistance to oxidative stress, which were recovered after in 40 min of rest. Erythrocyte antioxidant enzymes activities remained unchanged during the training either with regular clothes or personal protective equipment. [Conclusion] These results suggest that wearing personal protective equipment during firefighting work could induce oxidative stress, which was enough to produce DNA damage in leukocytes.

DNA Protection against Oxidative Damage Using the Hydroalcoholic Extract of Garcinia mangostana and Alpha‐Mangostin

Garcinia mangostana, popularly known as “mangosteen fruit,” originates from Southeast Asia and came to Brazil about 80 years ago where it mainly grows in the states of Pará and Bahia. Although mangosteen or its extracts have been used for ages in Asian folk medicine, data on its potential genotoxicity is missing. We, therefore, evaluated genotoxicity/mutagenicity of hydroethanolic mangosteen extract [HEGM, 10 to 640 μg/mL] in established test assays (Comet assay, micronucleus test, and Salmonella/microsome test). In the Comet assay, HEGM-exposed human leukocytes showed no DNA damage. No significant HEGM-induced mutation in TA98 and TA100 strains of Salmonella typhimurium (with or without metabolic activation) was observed and HEGM-exposed human lymphocytes had no increase of micronuclei. However, HEGM suggested exposure concentration-dependent antigenotoxic potential in leukocytes and antioxidant potential in the yeast Saccharomyces cerevisiae. HEGM preloading effectively protected against H2O2-induced DNA damage in leukocytes (Comet assay). Preloading of yeast with HEGM for up to 4 h significantly protected the cells from lethality of chronic H2O2-exposure, as expressed in better survival. Absence of genotoxicity and demonstration of an antigenotoxic and antioxidant potential suggest that HEGM or some substances contained in it may hold promise for pharmaceutical or nutraceutical application.

Leukocyte DNA damage after reduced and conventional absorbed radiation doses using 3rd generation dual-source CT technology

PurposeComputed tomography (CT) scans are an important source of ionizing irradiation (IR) in medicine that can induce a variety of DNA damage in human tissues. With technological improvements CT scans at reduced absorbed doses became feasible presumably lowering genotoxic side effects. Materials and methodsFor measuring DNA damage we performed γH2AX foci microscopy in peripheral blood mononuclear cells (PBMC) after exposure to reduced and conventional absorbed radiation doses using 3rd generation dual-source CT (DSCT) technology. ResultsCT scans performed at reduced absorbed doses of 3mGy induced significant lower levels (p<0.0001) of DNA damage (0.05 focus per cell±0.01 [mean±standard error of mean]) at 5min after IR compared to conventional absorbed doses of 15mGy (0.30 focus per cell±0.03). With ongoing DNA repair background γH2AX foci levels (0.05 focus per cell) were approached at 24h after CT with both protocols. ConclusionOur results provide evidence that reduced absorbed doses mediated by adjusted tube current in 3rd generation DSCT induce lower levels of DNA damage in PBMC compared to conventional absorbed doses suggesting a lower genotoxic risk for state-of-the-art tube current reduced CT protocols.

Oxidative Status and DNA Damage Following Analgesic Treatment in Patients with Acute Pancreatitis.

This study is designed to investigate the effect of three different analgesics, used to treat pain in AP, on oxidative stress, DNA damage in mononuclear leukocytes, and on oxidative status. This parallel design randomized controlled trial is composed of three treatment arms, intravenous paracetamol, intravenous dexketoprofen, and intravenous tramadol. A total of 107 patients were diagnosed with acute pancreatitis within the study period in the ED. Seventyseven of them were included in the study; 26 patients for the paracetamol group, 24 patients for the dexketoprofen group, and 27 patients for the tramadol group. The mean age of study subjects was 52.73 ± 15.38 and 66% (n = 51) of them were men. At the beginning of the study (before treatment), mean levels of DNA damage, TOS, and OSI levels were significantly higher and TAS was significantly lower in the acute pancreatitis groups than in the control group. DNA damage and OSI in HAPS-positive patients were found to be significantly greater than HAPS-negative patients (p = 0.046). DNA damage and oxidative stress were compared between the three groups. There were no differences between the groups in terms of DNA damage (p = 0.42) and also for the oxidatif stress parameters (OSI,TAS,TOS had p-values of p = 0.26, p = 0.78, p = 0.35, respectively). There is no difference between the effects of paracetamol, dexketoprofen, and tramadol, which are commonly used to manage acute pain in AP, on DNA damage in human T-lymphocytes and on serine parameters of oxidative status.

Oxidative DNA Damage to Sperm Cells and Peripheral Blood Leukocytes in Infertile Men.

BackgroundOxidative DNA damage is associated with male infertility. The aim of this study was to evaluate the oxidative DNA damage of sperm cells and blood leukocytes and to determine the levels of MDA and NO levels in seminal and blood plasma of idiopathic infertile men.Material/MethodsThe study enrolled 52 patients, including 30 infertile and 22 fertile men. MDA, NO, and 8-OHdG/106dG were estimated using spectrophotometry and high-pressure liquid chromatography (HPLC)-based methods in seminal and blood plasma. The association with the sperm parameters was assessed, particularly sperm counts and motility.ResultsThe mean sperm concentration and sperm motility of the fertile men were significantly higher than that of the infertile men. The mean MDA and NO concentration in the seminal and blood samples of the infertile men were higher than that of fertile men. Also, the mean numbers of sperm cells and leukocytes 8-OHdG/106dG of the infertile men were significantly higher than that of fertile men (p=0.04 and p<0.001, respectively). Sperm motility and sperm count were negatively correlated with leukocyte and sperm cell 8-OHdG/106dG ratio. However, progressive motility was significantly negatively correlated with sperm cell and leukocyte 8-OHdG/106dG ratio (R=−0.357, p=0.026; R=−0.388, p=0.024, respectively).ConclusionsOxidative stress is an important factor in male infertility. Therefore, biochemical detection of 8-OHdG/106dG in sperm cells and blood leukocytes may be an additional tool in the diagnosis of male infertility.

Genotoxic effects of chromium oxide nanoparticles and microparticles in Wistar rats after 28 days of repeated oral exposure

The nanotechnology industry has advanced rapidly in the last 10 years giving rise to the growth of the nanoparticles (NPs) with great potential in various arenas. However, the same properties that make NPs interesting raise concerns because their toxicity has not been explored. The in vivo toxicology of chromium oxide (Cr2O3)-NPs is not known till date. Therefore, this study investigated the 28-day repeated toxicity after 30, 300 and 1000 mg/kg body weight (bw)/day oral treatment with Cr2O3-NPs and Cr2O3 microparticles (MPs) in Wistar rats. The mean size of Cr2O3-NPs and Cr2O3-MPs was 34.89 ± 2.65 nm and 3.76 ± 3.41 μm, respectively. Genotoxicity was assessed using comet, micronucleus and chromosomal aberration (CA) assays. The results revealed a significant increase in DNA damage in peripheral blood leucocytes and liver, micronuclei and CA in bone marrow after exposure of 300 and 1000 mg/kg doses of Cr2O3-NPs and Cr2O3-MPs only at 1000 mg/kg bw/day. Cr biodistribution was observed in all the tissues in a dose-dependent manner. The maximum amount of Cr was found in the kidneys and least in the brain of the treated rats. More of the Cr was excreted in the faeces than in the urine. Furthermore, nanotreated rats displayed much higher absorption and tissue accumulation. These findings provide initial data of the probable genotoxicity and biodistribution of NPs and MPs of Cr2O3 generated through repeated oral treatment.

DNA damage in a patient with Systemic Lupus Erythematosus and Nephropathy- A Case Report

Objectives: Systemic Lupus Erythematosus (SLE) is a complex, multisystem autoimmune inflammatory disease. The inflammatory response in SLE exacerbates oxidative stress which tends to promote lipid peroxidation, protein oxidation and damage to DNA. Documentation of manifestation of DNA damage in SLE patients is scarce and related studies have not come to attention from this part of the world, therefore the present study showcases a case report on SLE. Methods: Assessment of DNA damage in peripheral blood leukocytes and oxidative stress biomarkers in blood sera of a 12y-old male presenting with SLE and nephropathy (on dialysis therapy) was made. Results: Basal DNA damage in PBL scored as percent DNA in tail was higher (51.48%) compared to levels (40.38%) in an age-and sex-matched healthy control. Quantitative measures of DNA damage revealed DF of 96 vs. 94 and DI of 317 vs . 208 in the case and the control, respectively. Serum lipid peroxidation as estimated from MDA level was 3x higher (1.759mol/l) compared to its level in a healthy control (0.571mol/l). OSI was slightly higher in the patient (0.134 arbitrary units) compared to that in the control (0.132 arbitrary units). The atherogenic indices were higher in the present case compared to ratios in the control. Conclusion: The results from the case report on increased oxidative stress, dyslipidemia, genetic damage and atherogenic indices support observations from earlier studies and imply onset of other complications in patients with SLE. The assessment of various blood-based biomarkers (as carried out in the present case) in SLE patients may assist in disease diagnosis, prognosis and optimal disease management.

Yacon (Smallanthus sonchifolius) and Lactobacillus acidophilus CRL 1014 reduce the early phases of colon carcinogenesis in male Wistar rats

The modifying effects of aqueous yacon extract (AYE) and Lactobacillus acidophilus CRL 1014 against colon carcinogenesis induced by 1,2-dimethylhydrazine (DMH) in male Wistar rats were investigated. Animals were allocated into five groups: G1: untreated group; G2: DMH-treated group; G3: DMH+L. acidophilus-treated group; G4: DMH+AYE-treated group; G5: DMH+L. acidophilus and AYE-treated group. A significant reduction (p<0.05) in leukocyte DNA damage and in colonic cell proliferation was observed after the first DMH administration in G3 (probiotic), G4 (prebiotic) and G5 (synbiotic) groups. In this moment, a significant increase (p<0.05) in colonic apoptosis was also observed in G3 (probiotic) and G5 (synbiotic) groups. In special, at five months after DMH administrations, a significant reduction (p<0.05) in ACF development was observed in G3 (probiotic), G4 (prebiotic) and G5 (synbiotic) groups. Incidence of colon tumors was lower at five months in G4 (prebiotic) and G5 (synbiotic) groups but not in eight months after DMH administrations. In conclusion, the findings suggest that the oral treatments have potential effects as a chemopreventive agent against colon carcinogenesis on an early stage of tumor development.

Age dynamics of DNA damage and CpG methylation in the peripheral blood leukocytes of mice

Certain types of DNA damage are known to accumulate with age. Here we present the quantitative data describing the extent of the spontaneous DNA damage in 144 SHK mice of various ages. In each animal, we assessed double strand breaks, single strand breaks and alkali-labile sites, as well as amounts of oxidized purines, oxidized pyrimidines and misincorporated uracils. In addition, overall levels of genome DNA methylation were evaluated. The amounts of oxidized pyrimidines were correlated with age in males only, while the amounts of double strand breaks (DSB) in DNA samples were correlated with age in females only (R=0.26; p<0.035). No age-related accumulation of single-strand breaks (SSB) was observed. The hypomethylation of DNA was significant in aging females, but not in aging males. Various types of DNA damage were correlated to each other. In attempt to develop more stable indicator of age-dependent alterations in DNA, the DNA Damage Level Differential (DDLD) indices was developed for comet assaying of peripheral blood leukocytes. As expected, DDLD index was shown to be better correlated with age than any single quantitative measure reflecting certain type of DNA damage. A variability of effectiveness of various kinds of DNA repair in individual animals was larger than expected. This conclusion may have a substantial impact on subsequent studies of the mutagens and other kinds of environmental stressors in animal populations. Nor DDLD neither individual quantitative measures of DNA damage were capable of prediction post-sampling survival time.

Protective effect of antioxidants on DNA damage in leukocytes from X-linked adrenoleukodystrophy patients

Toxic metabolites accumulation and oxidative stress have been associated to the pathophysiology of X-linked adrenoleukodystrophy (X-ALD), an inborn error of peroxisome metabolism. Parameters of oxidative damage to proteins and lipids in X-ALD patients were already described in literature; however, DNA injuries were not studied yet. Considering that, the aims were to investigate DNA damage by comet assay in heterozygotes and symptomatic X-ALD patients, to look for associations between DNA damage and lipid peroxidation as measured by urinary 15-F2t-isoprostane; and to evaluate the in vitro effect of N-acetyl-l-cysteine (NAC), trolox (TRO) and rosuvastatin (RSV) on DNA damage in leukocytes from symptomatic patients. Symptomatic patients presented higher DNA damage levels than those found in heterozygotes and controls; heterozygotes and controls showed similar results. In order to investigate the in vitro antioxidant effect on DNA damage, whole blood cells from symptomatic patients were incubated with NAC (1 and 2.5mM), TRO (25 and 75μM) and RSV (0.5, 2 and 5μM) before DNA damage analysis. NAC, TRO and RSV, at all tested concentrations, were all capable to reduce DNA damage in symptomatic X-ALD patients until control levels. Finally, DNA damage correlated with urinary isoprostanes and plasmatic levels of TBA-RS and DCFH-DA, allowing to hypothesize that DNA damage might be induced by lipid peroxidation in symptomatic patients. The present work yields experimental evidence that NAC, TRO and RSV reduce the in vitro DNA injury in symptomatic X-ALD patients, what may suggest that the administration of these antioxidants might be considered as an adjuvant therapy for X-ALD.

Increased DNA damage and oxidative stress among silver jewelry workers.

Silver has long been valued as a precious metal, and it is used to make ornaments, jewelry, high-value tableware, utensils, and currency coins. Human exposures to silver and silver compounds can occur oral, dermal, or by inhalation. In this study, we investigated genotoxic and oxidative effects of silver exposure among silver jewelry workers. DNA damage in peripheral mononuclear leukocytes was measured by using the comet assay. Serum total antioxidative status (TAS), total oxidative status (TOS), total thiol contents, and ceruloplasmin levels were measured by using colorimetric methods among silver jewelry workers. Moreover, oxidative stress index (OSI) was calculated. Results were compared with non-exposed healthy subjects. The mean values of mononuclear leukocyte DNA damage were significantly higher than control subjects (p < 0.001). Serum TOS, OSI, and ceruloplasmin levels were also found to be higher in silver particles exposed group than those of non-exposed group (p < 0.001, p < 0.001, p < 0.01, respectively). However, serum TAS levels and total thiol contents of silver exposed group were found significantly lower (p < 0.05, p < 0.001, respectively). Exposure to silver particles among silver jewelry workers caused oxidative stress and accumulation of severe DNA damage.