Effects of low-dose radiation on oxidative stress and damage repair in HBE cells / 中国辐射卫生

@#<b>Objective</b> To investigate the effects of lowdose ionizing radiation (LDIR) on oxidative stress and damage repair in human bronchial epithelial (HBE) cells. <b>Methods</b> HBE cells were divided into 0, 50, 100, and 200 mGy groups, and cultured for 24 and 48 h after X-ray irradiation, respectively. The cell viability, levels of glutathione (GSH), malondialdehyde (MDA), and 8-hydroxy-2’-deoxyguanosine (8-OHdG), and transcriptional levels of DNA damage repair genes <i>PPP2R2D</i> and <i>TP53</i> were measured. <b>Results</b> At 24 h after irradiation, there was no significant difference in the cell viability between the dose groups and the control group (<i>P</i> > 0.05); all dose groups had significantly increased MDA level, dose-dependently decreased GSH level, dose-dependently increased 8-OHdG level, and significantly increased mRNA level of <i>PPP2R2D</i> gene (all <i>P</i> < 0.05); the mRNA expression level of <i>TP53</i> gene was significantly increased in the 50 mGy group (<i>P</i> < 0.05). At 48 h after irradiation, there were the highest cell viability, significantly decreased MDA and 8-OHdG levels, and significantly increased mRNA expression levels of <i>PPP2R2D</i> and <i>TP53</i> genes in the 50 mGy group compared with the control group (all <i>P</i> < 0.05); the GSH level in the 100 mGy group was significantly increased (<i>P</i> < 0.05). <b>Conclusion</b> LDIR, especially radiation at 50 mGy, can affect the oxidative-antioxidant level in HBE cells and the transcript-level differential expression of DNA damage repair genes.

Ensayo del cometa como bioindicador de inestabilidad genómica en pacientes diabéticos hemodializados / Comet assay as a bioindicator of genomic instability in hemodialysis diabetic patients

Introducción: Procesos como la mutagénesis, la carcinogénesis y la teratogénesis son producto de la interacción de agentes de origen endógeno como exógeno que interactúan con la molécula de ADN en forma crónica produciendo rupturas en la doble hélice, y en cromosomas completos resultando en la inestabilidad genómica. El estrés oxidativo al que se encuentran sometidas las células al formarse las especies reactivas de oxígeno (ROS) y también las especies reactivas de nitrógeno (RNS), que pueden provenir de radicales producidos a consecuencia de la diabetes o en estados iniciales de la enfermedad renal crónica o como respuesta a procesos inflamatorios en estados avanzados de estas patologías, actúan como agentes genotóxicos endógenos.Objetivos: Esta investigación tuvo como objetivo determinar el daño basal en la molécula de ADN de pacientes diabéticos hemodializados, a través del ensayo del Cometa, como un bioindicador de inestabilidad genómica., durante seis meses de tratamiento. Materiales y métodos: Se planteó un estudio longitudinal prospectivo de cohorte para comparar los diferentes niveles de daño antes y durante los primeros seis del tratamiento de hemodiálisis. Se evaluó con el test del cometa o electroforesis de células individuales, el daño basal en muestras de sangre venosa de pacientes diagnosticados con Diabetes de tipo II como control negativo y en pacientes diabéticos con enfermedad renal crónica antes de iniciar el tratamiento de diálisis y luego durante el tratamiento. Se utilizó el test de t- Student para muestras independientes y emparejadas. Resultados: Se observó un aumento significativo de daño basal y oxidativo en el material genético de pacientes diabéticos con enfermedad renal crónica, comparados con los controles negativos (p< 0.005) y se observó, además, que el daño celular aumenta con el tratamiento de hemodiálisis (p<0.005). Conclusión: Los resultados obtenidos en esta investigación permiten concluir que el estrés oxidativo tiene un efecto genotóxico y que el nivel de daño genético es un buen bioindicador del avance de la enfermedad renal crónica y que la hemodiálisis induce a un aumento de daño a nivel del material genético, aumentando el riesgo de carcinogénesis.

Introduction: Processes such as mutagenesis, carcinogenesis and teratogenesis are the product of the interaction of agents of endogenous and exogenous origin that interact with the DNA molecule in a chronic way producing ruptures in the double helix, and in complete chromosomes resulting in genomic instability. The oxidative stress to which the cells are subjected when reactive oxygen species (ROS) and reactive nitrogen species (RNS) are formed, which may come from radicals produced as a result of diabetes or in initial stages of chronic kidney disease or in response to inflammatory processes in advanced stages of these pathologies, act as endogenous genotoxic agents. Objectives: This research aimed to determine the basal damage in the DNA molecule of hemodialyzed diabetic patients, through the Comet assay, as a bioindicator of genomic instability, during six months of treatment. Materials and methods: For this research, a prospective longitudinal cohort study was proposed to compare the different levels of genetic damage before and during the first six of hemodialysis treatment. Baseline damage was evaluated with the comet test or single cell electrophoresis, in venous blood samples from patients diagnosed with Type II Diabetes as a negative control and in diabetic patients with chronic kidney disease before starting dialysis treatment and then during treatment. Results: A significant increase in basal and oxidative damage was observed in the genetic material of diabetic patients with chronic kidney disease, compared to negative controls (p< 0.005) and it was also observed that cell damage increases with hemodialysis treatment (p<0.005). The t-Student test was used for independent and paired samples. Conclusion: The results obtained in this research allow us to conclude that oxidative stress has a genotoxic effect and that the level of genetic damage is a good bioindicator of the progression of chronic kidney disease and that hemodialysis induces an increase in damage at the level of the genetic material, increasing the risk of carcinogenesis.

Naringin attenuates oxidative stress, inflammation, apoptosis, and oxidative DNA damage in acrylamide-induced nephrotoxicity in rats

@# Objective: To explore the possible effects of naringin on acrylamide-induced nephrotoxicity in rats. Methods: Sprague-Dawley rats weighing 200-250 g were randomly divided into five groups. The control group was given intragastric (i.g.) saline (1 mL) for 10 d. The acrylamide group was given i.g. acrylamide in saline (38.27 mg/kg titrated to 1 mL) for 10 d. The treatment groups were administered with naringin in saline (50 and 100 mg/kg, respectively) for 10 d and given i.g. acrylamide (38.27 mg/kg) 1 h after naringin injection. The naringin group was given i.g. naringin (100 mg/kg) alone for 10 d. On day 11, intracardiac blood samples were obtained from the rats when they were under anesthesia, after which they were euthanized. Urea and creatinine concentrations of blood serum samples were analyzed with an autoanalyzer. Enzyme-linked immunosorbent assay was used to quantify malondialdehyde, superoxide dismutase, glutathione, glutathione peroxidase, catalase, tumor necrosis factor-β, nuclear factor-κB, interleukin (IL)-33, IL-6, IL-1β, cyclooxygenase-2, kidney injury molecule-1, mitogen-activated protein kinase-1, and caspase-3 in kidney tissues. Renal tissues were also evaluated by histopathological and immunohistochemical examinations for 8-OHdG and Bcl-2. Results: Naringin attenuated acrylamide-induced nephrotoxicity by significantly decreasing serum urea and creatinine levels. Naringin increased superoxide dismutase, glutathione, glutathione peroxidase, and catalase activities and decreased malondialdehyde levels in kidney tissues. In addition, naringin reduced the levels of inflammatory and apoptotic parameters in kidney tissues. The histopathological assay showed that acrylamide caused histopathological changes and DNA damage, which were ameliorated by naringin. Conclusions: Naringin attenuated inflammation, apoptosis, oxidative stress, and oxidative DNA damage in acrylamide-induced nephrotoxicity in rats.

Association of Oxidative Damage Measured by 8-hydroxyguanosine Formation with Altered Risks to Hepatocellular Carcinoma in Malaysian Study Population

@#Introduction: Oxidative damage is an important factor contributing to ageing and many degenerative diseases. It can be detected by the DNA base damage, which is formation of 8-oxo-7,8-dihydro-2’deoxyguanosine (8-oxodG). The 8-oxodG is an important indicator of oxidative stress and has been competently specified as a recognized initiator of the carcinogenic process and premutagenic injury in mammalian cells. Aims: In this preliminary study, we investigated the possible association of oxidative DNA damage in hepatocellular carcinoma (HCC) patients in comparison with Malaysian healthy controls taking into account the different races and genders in both groups. Method: DNA of peripheral white blood cells was isolated from 91 HCC patients and 304 controls. The level of oxidative DNA damage was determined by ELISA procedure. Results: Quantitative measurement of 8-oxodG was higher in HCC patients at mean value of 3.30 ± 2.32 ng/ml. In controls, the average value is 1.57 ± 1.92 ng/ml. Comparison between gender showed that there was a significant difference observed in the level of 8-oxodG between male and female in controls, where p = 0.003. The level of 8-oxodG was higher in male than in female controls. There was a significant difference in the average value of 8-oxodG level between the controls and HCC patients where p<0.001. However, no significant difference in the level of 8-oxodG value was observed when compared between Malays and the non-Malays. Conclusion: HCC patients showed greater oxidative damage to DNA as compared to controls and this suggests oxidative DNA damage may contribute to the pathogenesis of HCC.

Design, synthesis and biological evaluation of five-membered heterocyclopyrimidines as MTH1 inhibitors / 中国药科大学学报

@#Based on the reported inhibitors TH287, 17 five-membered heterocyclopyrimidine derivatives were designed and synthesized by cyclization, scaffold hopping, bioisosterism and molecular docking technology. The bioassays determined by malachite green method demonstrated that the target compounds displayed good inhibitory activity against MTH1. Among them, the IC50 value of 7 compounds was less than 1 μmol/L, suggesting that these compounds may be candidates for further investigation.

Expression and significance of 8-OHdG in primary pterygium / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM:To detect oxidative DNA damage marker 8-hydroxy-2-deoxyguanosine(8-OHdG)in primary pterygium and normal conjunctival tissues, explore the role of oxidative DNA damage in the pathogenesis of pterygium. <p>METHODS: Totally 35 primary pterygium specimens were collected during surgery and 5 normal conjunctival specimens which above the normal temporal bulbar conjunctiva were collected. The expressions of 8-OHdG in pterygium tissues were detected by immunohistochemical method and compared with the normal conjunctival tissues. The difference of 8-OHdG expression between the two groups was compared. <p>RESULTS: There were 24(69%)pterygium specimens positive for 8-OHdG staining, limited to the nuclei of the epithelial layer. No substantial staining was visible in the subepithelial fibrovascular layers. All normal controls were negative for 8-OHdG staining. The difference of 8-OHdG expression between the two groups was statistically significant(<i>P</i>=0.007). <p>CONCLUSION: The increased levels of 8-OHdG in the pterygium tissues indicate that oxidative DNA damage maybe play an important role in the pathogenesis of pterygium.

Expression of 8-oxodG in Oral Leukoplakia / 沈阳医学院学报

Objective:To study the expression of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) in oral leukoplakia for clarifying the role of oxidative DNA damage in the development of oral leukoplakia. Methods:Immunofluorescence labeling method was used to examine the expression of 8-oxodG,a marker of oxidative DNA damage,and the expression of tumor suppressor gene, P53 protein in oral epithelium of normal oral mucosa and biopsy specimens of leukoplakia. Results:In specimens of oral leukoplakia, HE staining showed infiltration of inflammatory cells, hyperkeratosis and epithelial dysplasia. Immunofluorescence labeling study demonstrated that the accumulation of 8-oxodG apparently increased in the oral epithelium of patients with leukoplakia,whereas little or no immunoreactivity was observed in normal oral mucosa. Expression of P53 protein was also observed in oral epithelium of patients with oral leukoplakia. The immunoreactivity of 8-oxodG and P53 was stronger in patients with oral leukoplakia than that in normal oral mucosa (P<0.01) . Moreover,the immunoreactivity increased with the development of disease (r=0.773, P<0.01) . Conclusions:The oxidative DNA damage contributes to the development of oral leukoplakia. 8-oxodG may be a risk predictive marker for oral leukoplakia.

Oxidative DNA Damage in Gestational Diabetes Mellitus: Correlation with Antioxidants in an Iraqi Cohort.

This study aimed to evaluate the degree of oxidative stress in gestational diabetes mellitus when compared to non-diabetic pregnant women. Methodology: This cross-sectional study included 73 participants (29 gestational diabetic women and 44 control pregnant women) attending the Maternal and Childhood Unit, Al- Husayniya Medical Centre, Baghdad, Iraq. The data was analyzed using SPSS (Version 14) and Microsoft Excel (Office2007, Microsoft). All values were expressed as mean±standard deviation (M±SD). Results: Serum 8-Hydroxy-2-Deoxyguanosine was significantly (P < .001) greater in the gestational diabetes mellitus group compared to control group (57.2±17.6 ng/dl versus 19.8±7.8ng/dl respectively). The increase in 8-Hydroxy-2-Deoxyguanosine was associated with a significant (P < .001) elevation in serum malondialdehyde level (2.1±0.8 nmol/ml versus 1±0.4 nmol/ml) and a significant (P =.05) reduction in plasma reduced glutathione in the gestational diabetes mellitus group compared to the control group (20.6±5 mg/dl compared to 24.1±4.4 mg/dl). A significant change in total cholesterol (5.4±1.1mmol/L) and low density lipoprotein cholesterol (3.3±0.9mmol/L) were also noted in gestational diabetes mellitus group compared to the control group (4.7±1.3mmol/L and 2.8±1mmol/L respectively) at P =.05. Conclusion: An increase in 8-Hydroxy-2-Deoxyguanosine is associated with higher levels of malondialdehyde and a significant reduction in reduced glutathione in gestational diabetes mellitus group, suggesting that significant oxidative stress associated with lipid peroxidation is occurring. Measuring these markers is useful in monitoring gestational diabetes mellitus to prevent the negative outcomes of gestational diabetes mellitus such as increased risk of diabetes and fetal morbidity.

Evaluating Markers of Oxidative Stress in Managing Gestational Diabetes Mellitus: A Cross Sectional Study in Iraq.

Aims: The objective of the present study was to evaluate the association of oxidative stress markers and antioxidants in gestational diabetes when compared to non-diabetic pregnant women. Methodology: This is a cross-sectional study, conducted in Al-Husayniya Medical Centre, Baghdad, Iraq and included 73 participants attending the Maternal and Childhood Unit for the period between January 2008 and May 2010. Results: Serum 8-Hydroxy-2-Deoxyguanosine was significantly greater in the gestational diabetes mellitus group compared to control group (57.2±17.6ng/dl versus 19.8±7.8ng/dl respectively, P<.05). The increase in 8-Hydroxy-2-Deoxyguanosine was associated with a significant elevation in serum total cholesterol and high density lipoprotein cholesterol and a significant reduction in serum superoxide dismutase in the gestational diabetes mellitus group compared to the control group at P<.05. A significant negative correlation was noted between 8-Hydroxy-2-Deoxyguanosine and superoxide dismutase among all the participants included in this study (r=0.66 at P<.05). Conclusions: The current study proves the importance of measuring markers of oxidative stress (expressed by serum 8-Hydroxy-2-Deoxyguanosine & serum lipids) and antioxidants (expressed by serum superoxide dismutase) in managing cases of gestational diabetes mellitus and provides a useful way of assessing the disease progression and/or remission in response to the treatment.

Association between dyslipidemia and 8-OHdG/Cr among a population exposed to chronic arsenic / 中华流行病学杂志

Objective To explore the association between dyslipidemia and the level of 8-OHdG/Cr in urine among a population exposed to chronic arsenic.Methods Four hundred and seven subjects were randomly selected in an arsenic-affected area in Inner Mongolia.After blood biochemical examination,all the subjects were divided into 4 groups based on the results of total cholesterol (TC),triglycerides (TG),high density lipoprotein cholesterol (HDL-C) and low density lipoprotein cholesterol (LDL-C).The groups consisted of hypercholesterolemia,HDL-C ratio anomaly,combined hypercholesterolemia and HDL-C ratio anomaly,as well as a normal lipid group.Urine samples were collected and 8-OHdG/Cr was measured using the ELISA method.A generalized linear mixed model was used to analyze the association between dyslipidemia and 8-OHdG/Cr.Results The levels of 8-OHdG/Cr as 55.73 (39.90-79.94) ng/mg,58.08 (44.94-69.91) ng/mg,65.28 (49.29-92.95) ng/mg and 51.43 (36.86-68.57)ng/mgin the HDL-C ratio anomaly,hypercholesterolemia,combined hypercholesterolemia and HDL-C ratio anomaly groups and the control group,respectively,which showed significant differences on the levels of 8-OHdG/Cr in the four groups (P=0.006).From the linear regression analysis results showed that the 8-OHdG/Cr level incombined hypercholesterolemia and HDL-C ratio anomaly group was higher (4.25 ± 0.55 ng/mg) than in the control group (3.96 ± 0.55 ng/mg) (P=0.018).After adjusting for important covariates,there was a linear trend between the levels of 8-OHdG/Cr and dyslipidemia (P=0.016).Conclusion Data from our study showed a linear relation between hypercholesterolemia,HDL-C ratio anomaly and the 8-OHdG/Cr level,suggesting that dyslipidemia was associated with oxidative DNA damage among those arsenic-affected people.

Change in serum level of 8-hydroxy-deoxyguanosine during corticosteroid treatment in patients with active Graves' ophthalmopathy / 中华内分泌代谢杂志

The change in serum level of 8-hydroxy-deoxyguanosine (8-OHdG),an oxidative stress biomarker,in patients with active Graves' ophthalmopathy (GO) during corticosteroid treatment was observed.The serum level of 8-OHdG was significantly increased in patients with active GO as compared with that of normal controls and patients with Graves' disease (P ＜ 0.05).After systemic corticosteroid treatment,patients with GO showed significantly lowered 8-OHdG level as compared with that before treatment and patients with Graves' disease.These changes in serum 8-OHdG level were accompanied by decreases in clinical activity score (P ＜ 0.05) during corticosteroid treatment.Oxidative stress may play a role in the pathogenesis of GO.Serum 8-OHdG level may be used as an objective and quantitative parameter in patients with GO during immunosuppressive treatment.

Lipid peroxidation and DNA damage in different stages of acute renal failure.

Introduction: Oxidative stress is an imbalance between the formation of Reactive oxygen species and protective antioxidant defense. It is known that oxidative stress increases the Acute renal failure. Measurement of oxidative stress parameters may be a simple tool for monitoring the progression of acute renal failure. Aim: The aim of this study was to evaluate oxidative stress in acute renal failure patients by Lipid peroxidation product Malondialdehyde (MDA), Total antioxidant capacity (TAC) and oxidative DNA damage product and compare its level among the patients of varying severity as per RIFLE classification. Materials and methods. We conducted a cross sectional study to compare oxidative stress parameters. Blood samples were collected from 62 patients with ARF, admitted to the Vinayaka Mission’s Medical College & Hospital, Salem from March 2009 to July 2010. We further subdivided the patients according to RIFLE classification. Results: The levels of MDA, Index of oxidative status MDA/TAC and DNA damage product 8 OH deoxy guanosine were significantly higher among failure group when compared to risk and injury. Total antioxidant capacity and super oxide dismutase (SOD) were found to be decreased.

Modulatory effect of plasma folate and polymorphisms in one-carbon metabolism on catecholamine methyltransferase (COMT) H108L associated oxidative DNA damage and breast cancer risk.

The present study was aimed to investigate the modulatory role of plasma folate and eight putatively functional polymorphisms of one-carbon metabolism on catecholamine methyltransferase (COMT)-mediated oxidative DNA damage and breast cancer risk. Plasma folate and 8-oxo-2’-deoxyguanosine (8-oxodG) were estimated by commercially available kits, while polymorphisms were screened by PCR-RFLP and PCR-AFLP methods. COMT H108L polymorphism showed independent association with breast cancer (OR: 1.73, 95% CI: 1.31-2.30). No significant interaction was observed between folate status and COMT genotype. Multifactor dimensionality reduction (MDR) analysis gave evidence for the significant epistatic (gene-gene) interactions (p<0.0001) of COMT H108L with reduced folate carrier 1 (RFC1) G80A, thymidylate synthase (TYMS) 5’-UTR 3R2R, TYMS 3’-UTR ins6/del6. Increased plasma 8-oxodG were observed in cases compared to controls (mean ± SE: 5.59 ± 0.60 vs. 3.50 ± 0.40 ng/ml, p<0.004). Plasma folate deficiency alone was not a significant predictor of 8-oxodG elevation. The genotype combinations namely, RFC1 G80A/methionine synthase reductase (MTRR) A66G, RFC1 G80A/SHMT C1420T/TYMS 3R2R and serine hydroxymethyltransferase (SHMT) C1420T/TYMS 3R2R/methionine synthase (MTR) A2756G/COMT H108L were strong predictors of 8-oxodG elevation in the order of risk. To conclude, the current study provides substantial evidence for a cross talk between one-carbon metabolism and COMT catalysis that might influence oxidative DNA damage and breast cancer risk.

Effect of surgical stress on nuclear and mitochondrial DNA from healthy sections of colon and rectum of patients with colorectal cancer.

Surgical resection at any location in the body leads to stress response with cellular and subcellular change, leading to tissue damage. The intestine is extremely sensitive to surgical stress with consequent postoperative complications. It has been suggested that the increase of reactive oxygen species as subcellular changes plays an important role in this process. This article focuses on the effect of surgical stress on nuclear and mitochondrial DNA from healthy sections of colon and rectum of patients with colorectal cancer. Mitochondrial DNA copy number, mitochondrial common deletion and nuclear and mitochondrial 8-oxo-2′-deoxyguanosine content were measured. Both the colon and rectal tissue were significantly damaged either at the nuclear or mitochondrial level. In particular, mitochondrial DNA was more damaged in rectum than in colon. The present investigation found an association between surgical stress and nuclear and mitochondrial DNA damage, suggesting that surgery may generate an increase in free radicals, which trigger a cascade of molecular changes, including alterations in DNA.

Inhibitory effect of antioxidants on the benz[a]anthracene-induced oxidative DNA damage in lymphocyte.

Benz[a]anthracene is a ubiquitous environmental contaminant formed during the incomplete combustion of organic material. Some of the metabolites of benz[a]anthracene are known to be toxic and carcinogenic. In this investigation, benz[a]anthracene-induced oxidative damage to lymphocyte DNA was evaluated with the Comet assay (single cell gel electrophoresis). The level of oxidative DNA damage caused by benz[a]anthracene increased in a dose-dependent manner (24, 49) and oxidative DNA damage was significantly inhibited by 5 and 10 μg ml-1 ascorbate, 5 μg ml-1 polyphenols, as well as 5 and 10 μg ml-1 curcumin. Moreover, traditional Korean medicinal herbs such as Acanthopanax and ginseng significantly reduced DNA damage. The results demonstrate that antioxidant supplementation to lymphocytes inhibits oxidative DNA damage in vitro, supporting an inhibitory effect against oxidative DNA damage, probably due to reduction of reactive oxygen species production induced by benz[a]anthracene.

ANTIOXIDANT SUPPLEMENTATION DECREASES THE AMOUNT OF URINARY 8-OHdG EXCRETION INDUCED BY A SINGLE BOUT OF EXERCISE / 体力科学

The purpose of this study was to investigate the intensity of exercise load which increases urinary 8-hydroxydeoxyguanosine (8-OHdG) excretion and the effect of antioxidant supplementation on urinary 8-OHdG excretion after a single bout of exercise. The subjects included 6 healthy males with the following characteristics : age ; 24.0±1.1 years, height ; 174.0±8.5 cm, weight ; 71.5±15.4 kg, BMI ; 23.2±3.4 kg/m². The urinary concentration of 8-OHdG was measured by the two-column-switching high-performance liquid chromatography (HPLC) method. After 7 days of supplementation, the time course of the urinary 8-OHdG excretion was observed following treadmill running at 70% VO₂max.Significant increases in the urinary 8-OHdG excretion were detected at 2 h (p<0.01) and 4 h (p<0.05) after exercise.After 7 days of supplementation, a significant increase in the urinary 8-OHdG excretion was detected 1 h after exercise (p<0.05); however, it returned to the initial level 2 h after exercise. Therefore, oxidative DNA damage induced by a single bout of exercise was diminished by antioxidant supplementation.

The Effects of Purple Grape Juice Supplementation on Improvement of Antioxidant Status and Lymphocyte DNA Damage in Korean Smokers

The purpose of this project was to evaluate whether daily fruit juice consumption could reduce the DNA damage in healthy subjects. The study was performed using 67 healthy volunteers (29 smokers, 38 nonsmokers) who were supplemented with 480 ml of grape juice for 8 weeks. Eight weeks of grape juice consumption did not change any anthropometric parameters. Lymphocyte DNA damage before the study was significantly greater (p < 0.05) in smoker than nonsmoker, but, grape juice consumption significantly reduced DNA damage in both smoker (26%) and nonsmoker (17%) to the level where there was no difference remained between the two groups after the intervention trial. This preventive effect of grape juice against DNA damage was not affected by sex of the subjects in non-smokers. Plasma alpha-carotene, lycopene and gamma-totopherol was significantly increased after the trial in smokers, while erythrocyte catalase was significantly increased in both smokers and nonsmokers. Total radical-trapping antioxidant potential (TRAP) level in all subjects was significantly reduced after the intervention, while GSH-Px activity was increased only in nonsmokers. These results suggests that daily consumption of grape juice may protect DNA damage in peripheral lymphocytes, and supports the hypothesis that grape juice might exert their effect partially via a decrease in oxidative damage to DNA in humans partly by improving their antioxidative defense system.

Effect of Deer Antler Drink Supplementation on Blood Pressure, Blood Glucose and Lymphocyte DNA Damage in Type 2 Diabetic Patients

Deer Antler has been known for its traditional oriental medicinal properties and has been widely used to promote growth, boost immune function, treat blood loss and chronic joint pain. Recent study showed imported (New Zealand) Deer Antler was beneficial in reducing the side effects of cancer treatments. However, there was no intervention study conducted on the effect of Korean Deer Antler on reducing the oxidative stress to patients with diabetes. One of the sensitive ways to measure endogenous oxidative stress is by measuring cellular DNA damage using single cell gel electrophoresis (COMET assay). This study was conducted to investigate the possible beneficial effect of commercial Deer Antler drink (provided by Chung-yang Deer Farm) on lymphocyte DNA damage and blood glucose of diabetic patients. Ten patients (4 men, 6 women) participated in the study and consumed 2 pouches of Deer Antler drink every day for 20 days. Blood was collected on the morning before and after the intervention for lymphocyte isolation and blood glucose analysis. Both systolic and diastolic blood pressure showed a tendency to decrease but did not reach statistical significance after the trial. Blood glucose level was not affected by the supplementation. After the intervention, over 50% reduction were noted in the cellular DNA damage, expressed as tail length (TL) and tail moment (TM; tail length x percent tail DNA). Although we did not obtain beneficial effect on lowering blood glucose levels in the patients, this results suggest that Deer Antler may initially act in protecting endogenous DNA damage in short-term experiment.

Plasma, Tissue Thiobarbituric Acid Reactive Substance and Lymphocyte Oxidative DNA Damage in Mouse Fed Gamma Irradiated Diet

Food irradiation has been steadily increasing in many countries in line with increasing international trade and concerns about naturally occurring harmful contaminants in food. Although irradiation provides an excellent safeguard for the consumer by destroying almost 100% of harmful bacteria, it is necessary to ensure the safety of irradiated foods. This study was performed to investigate the effect of an irradiated diet on lipid peroxidation in the plasma, liver, small intestinal mucosa, and lymphocyte DNA damage in mice. Eight-week old ICR mice were assigned to two groups to receive either non-irradiated or irradiated (10 kGy) diets containing 20.38% fish powder and 6.06% sesame seeds for 4 weeks. The resulting changes in the degrees of lipid peroxidation were evaluated based on the level of plasma and liver thiobarbituric acid reactive substance (TBARS), transmission electron micrograph of jejunal mucosa, and free radical-induced oxidative DNA damage in lymphocytes, as measured by alkaline comet assay (single cell gel electrophoresis). The peroxide values of the gamma irradiated diet were measured every week, and the sample for comet assay was taken at the end of the four week experimental period. There was no significant difference in food efficiency ratio between the two groups. The peroxide values of the diet were immediately increased to 35.5% after gamma irradiation and kept on increasing during storage. After 4 weeks, no differences in tissue or plasma TBARS value were observed between the two groups, but epithelial cells of jejumum showed osmiophillic laminated membranous structures, considered as myelin figures,. The oxidative DNA damage expressed as tail moment (TM) increased 30% in the blood lymphocytes of the mice fed the irradiated diet. In conclusion, the comet assay sensitively detected differences in lymphocyte DNA damage after feeding with the irradiated diet for 4 weeks. However, in order to ensure the safety of irradiated foods, it would be more useful to conduct a long-term feeding regimen using an irradiated diet and examine the level of lipid peroxidation and the state of oxidative stress in a greater range of organs.

Reduction of TNF alpha-induced oxidative DNA damage product, 8-hydroxy-2'-deoxyguanosine, in L929 cells stably transfected with small heat shock protein

Previous studies have demonstrated that oxidative stress involving generation of reactive oxygen species (ROS) is responsible for the cytotoxic action of TNF alpha. Protective effect of small heat shock proteins (small HSP) against diverse oxidative stress conditions has been suggested. Although overexpression of small hsp was shown to provide an enhanced survival of TNF alpha-sensitive cells when challenged with TNF alpha, neither the nature of TNF alpha-induced cytotoxicity nor the protective mechanism of small HSP has not been completely understood. In this study, we have attempted to determine whether TNF alpha induces oxidative DNA damage in TNF alpha-sensitive L929 cells. We chose to measure the level of 8-hydroxy-2'-deoxyguanosine (8 ohdG), which has been increasingly recognized as one of the most sensitive markers of oxidative DNA damage. Our results clearly demonstrated that the level of 8 ohdG increased in L929 cells in a TNF alpha dose-dependent manner. Subsequently, we asked whether small HSP has a protective effect on TNF alpha-induced oxidative DNA damage. To accomplish this goal, we have stably transfected L929 cells with mouse small hsp cDNA (hsp25) since these cells are devoid of endogenous small hsps. We found that TNF alpha-induced 8 ohdG was decreased in cells overexpressing exogenous small hsp. We also found that the cell killing activity of TNF alpha was decreased in these cells as measured by clonogenic survival. Taken together, results from the current study show that cytotoxic mechanism of TNF alpha involves oxidative damage of DNA and that overexpression of the small hsp reduces this oxidative damage. We suggest that the reduction of oxidative DNA damage is one of the most important protective mechanisms of small HSP against TNF alpha.