Deoxyguanosine In Urine Research Articles

Effects of topical doxycycline on serum prooxidant marker levels in periodontal disease: A pilot study

The aim of this study is to determine the changes in the serum levels of malondialdehyde and 8-hydroxy-2'-deoxyguanosine, as indicators of oxidative stress, in response to periodontal treatment adyuvanted with topical doxycycline. Methods: Thirty four patients with periodontal disease were studied (DOX group n=16; Control group n=18), determining the serum levels of malondialdehyde and 8-hydroxy-2'-deoxyguanosine in urine at baseline and three months after non-surgical periodontal treatment. Results: We observed a slight trend to decrease in 8-OHdG urine levels after periodontal treatment, being this decrease greater in the DOX group (t1: 9.64 ± 7.18 μg/g; t0: 9.84 ± 3.01 μg/g) than in the control group (t1: 8.79 ± 4.08 μg/g; t0: 8.82 ± 4.01 μg/g). However, these changes were not statistically significant. No changes in serum levels of MDA were observed after periodontal treatment. BOP was positively correlated with 8-OHdG, in the DOX group (r = 0.563, p = 0.018). Conclusion: Periodontitis, as a local inflammatory disease, can cause an increase in oxidative stress, thus opening the way to new therapeutic strategies, while exploring novel strategies for modulating the host response.

Fluorescent Aptasensor for Determination of 8-Oxo-2′-deoxyguanosine in Urine Using Carbon Dots and Amine-Functionalized Gold Nanoparticles

Fluorescent Aptasensor for Determination of 8-Oxo-2′-deoxyguanosine in Urine Using Carbon Dots and Amine-Functionalized Gold Nanoparticles

HBM4EU Chromates Study-Genotoxicity and Oxidative Stress Biomarkers in Workers Exposed to Hexavalent Chromium.

A study was conducted within the European Human Biomonitoring Initiative (HBM4EU) to characterize occupational exposure to Cr(VI). Herein we present the results of biomarkers of genotoxicity and oxidative stress, including micronucleus analysis in lymphocytes and reticulocytes, the comet assay in whole blood, and malondialdehyde and 8-oxo-2′-deoxyguanosine in urine. Workers from several Cr(VI)-related industrial activities and controls from industrial (within company) and non-industrial (outwith company) environments were included. The significantly increased genotoxicity (p = 0.03 for MN in lymphocytes and reticulocytes; p < 0.001 for comet assay data) and oxidative stress levels (p = 0.007 and p < 0.001 for MDA and 8-OHdG levels in pre-shift urine samples, respectively) that were detected in the exposed workers over the outwith company controls suggest that Cr(VI) exposure might still represent a health risk, particularly, for chrome painters and electrolytic bath platers, despite the low Cr exposure. The within-company controls displayed DNA and chromosomal damage levels that were comparable to those of the exposed group, highlighting the relevance of considering all industry workers as potentially exposed. The use of effect biomarkers proved their capacity to detect the early biological effects from low Cr(VI) exposure, and to contribute to identifying subgroups that are at higher risk. Overall, this study reinforces the need for further re-evaluation of the occupational exposure limit and better application of protection measures. However, it also raised some additional questions and unexplained inconsistencies that need follow-up studies to be clarified.

Determination of 8−hydroxy−2ˊ−deoxyguanosine in urine with “linear” mode sparked graphite screen-printed electrodes

The development of sensors for diagnostic purposes is of immense importance. Despite the number of proposed sensors showing attractive detection capabilities, the widespread use of these sensors is mainly hindered by selectivity issues and the elaborate tailoring of the sensing surface that eventually increases both the cost of the final sensor and the individual analysis cost. Herein, we report on the development of an advanced sensor for 8−hydroxy−2ˊ−deoxyguanosine (8−OHdG), an important biomarker for DNA oxidative damage. The sensor was developed on a low-cost graphite screen-printed electrode (SPE) by employing for the first time, an extremely fast SPE-to-graphite “linear” mode sparking process that enables the uniform modification of the whole electrode surface in less than 20 s. Graphite-sparked SPEs exhibited a linear relationship with the concentration of 8−OHdG over the range 2–50 nM, while the limit of detection (3σ) was 0.35 nM. The sensors showed a notable resistance to interference by 1000-fold excess of dopamine and ascorbic acid, and 100-fold excess of uric acid. A simple treatment of the samples, based on uricase, that eliminates the interference caused by uric acid under real-world conditions (>1000-fold excess) was optimized and proposed. The method was successfully applied to the determination of 8−OHdG in synthetic urine samples. Recovery was 95%.

Overview of 8-hydroxy-2?-deoxyguanosine (8-ohdg) as DNA Damage Biomarker in Infants Who Live Near Gold Mines, Yogyakarta, Indonesia

Background: People living near gold mines have risks of Hg exposure. Hg as free radical will react to bodybiomolecules. Susceptible biomolecules are nucleic acid or DNA. With DNA damage biomarker using8-hydroxy-2?-deoxyguanosine(8-OhdG).Purpose: This research will give an overview of 8-OHdG in mother and infants living near gold mines.Research Method: This Observational Longitudinal research measures Hg level in mothers’ hair and urine,breast milk, cord blood, also infants’ hair and urine. Level of 8-hydroxy-2?-deoxyguanosine (8-OHdG) inurine is measured with Elisa Kit. Mercury Analyzerwas used to measure Hg.Results: Average of Hg in maternal hair and urine, cord blood, breast milk also infants’ hair and urine werehigh above Threshold Limit Value (TLV) by WHO. Showing occurrence of Hg accumulation in mothers.Infant Hg exposure has occurred during prenatal transferred through cord blood and postnatal through breastmilk. Average of 8-OHdG in maternal and infant urine were high above normal average level of peopleunexposed to Hg, i.e 2.28 nm/ml which shows occurrence of DNA damage.Conclusion: Maternal and infant Hg were high above TLV. Level of 8-OHdG in maternal and infant urinewere high above 8-OHdG level of people unexposed to Hg, indicating DNA damage inducted by mercury.

Nanosized zinc, epigenetic changes and its relationship with DMBA induced breast cancer in rats

Abstract The aim of the research was to compare the impact of nano- and micro-sized-zinc on the kinetics of changes in the level of 3-methyladenine, 7-methylguanine, 7-methylguanosine, O-methylguanosine, 1-methyladenosine, N6-methyl-2’-deoxyguanosine in urine of rats with breast cancer. Female Sprague-Dawley rats divided into 3 groups were used in the study. Animals were fed only a control diet or diets supplemented with the nano and micro-sized zinc particles. To induce the mammary cancer (adenocarcinoma), rats were treated with 7,12-dimethylbenz[a]anthracene (DMBA). Modified nucleosides were determined by a validated high performance liquid chromatography coupled to mass spectrometry method. In the first stage of investigations a synergistic activity of nanosized Zn with DMBA on the growth of the neoplastic process was found. During that time a statistically significant increase in the levels of all six examined markers in the rats’ urine was observed. However, as the experiment continued, the supplementation with nanosized zinc caused inhibition of tumour growth, being followed by regression and remission of tumours, as well as, a statistically significant systematic reduction of the levels of methyl derivatives in the urine. Biopsy images indicated grade 1 tumours with multiple inflammatory infiltrates in the group treated with zinc nanoparticles, whereas, in the other groups, moderately-differentiated grade 2 adenocarcinoma was identified. It was found that the biological activity of zinc depends on the size of applied particles, as the treatment with zinc microparticles has not had much effect on cancer progression.

Electrochemical Determination of 8-Nitroguanine and 8-Hydroxy-2`-Deoxyguanosine in Urine and Whole Blood Using Stochastic Sensors

Three stochastic sensors based on reduced graphene oxide (reduced nanographene oxide, reduced graphene oxide decorated with TiO2 and nanoparticles of Au or Ag) paste modified with a complex of protoporphyrin IX with zinc, are reported for the electroanalysis of 8-nitroguanine and 8-hydroxy-2`-deoxyguanosine in whole blood and urine samples. The highest sensitivity for the assay of the biomarkers was recorded for the sensor based on reduced graphene oxide decorated with TiO2 and gold nanoparticles. Recoveries higher than 96.00% were recorded with relative standard deviation (%) values lower than 1.00% when the sensors were used for the determination of biomarkers in both urine and whole blood samples, demonstrating that the proposed stochastic sensors may be reliably applied for the molecular recognition and quantitative determination of the two biomarkers used in the diagnosis of leukemia and gastric cancer.

Simultaneous determination of seven metabolites of organophosphate esters and 8-hydroxy-2'-deoxyguanosine in urine by high-performance liquid chromatography-tandem mass spectrometry with homemade mixed column purification

A method based on high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) with a small homemade mixed column was developed for the simultaneous determination of seven metabolites of organophosphate esters (OPEs) and 8-hydroxy-2'-deoxyguanosine (8-OHdG), an DNA oxidative damage marker, in urine. The urine samples were extracted by acetonitrile and enriched by the self-made column. All the samples were separated by gradient elution with acetonitrile-0.2% (v/v) ammonia solution, and then analyzed by an electrospray ionization source in negative ion multiple reaction monitoring mode. The results showed that the eight targets had good linearities in the range of 0.1-200 μg/L. The recoveries of the seven metabolites of OPEs and 8-OHdG in urine samples were in the ranges of 52.36% to 114.56% and 88.63% to 97.72%, respectively. The established method was successfully applied for the determination of the abovementioned eight target compounds in real urine samples, with the mass concentrations of the seven metabolites of OPEs and 8-OHdG being 6.24-46.07 μg/L and 5.90-16.71 μg/L, respectively. In addition, significant correlations were found between 8-OHdG and the total content of the seven metabolites of OPEs. The established method is simple, sensitive, accurate, and reproducible, and it provides reliable technical support for a more comprehensive evaluation of the level of human exposure to OPEs and the resulting health hazards.

Measurement of 8-oxo-7,8-dihydro-2′-deoxyguanosine in urine by an improved ELISA

Measurement of 8-oxo-7,8-dihydro-2′-deoxyguanosine in urine by an improved ELISA

C-X-C Chemokine Receptor Type 4 Plays a Crucial Role in Mediating Oxidative Stress-Induced Podocyte Injury.

Oxidative stress plays a role in mediating podocyte injury and proteinuria. However, the underlying mechanism remains poorly understood. In this study, we investigated the potential role of C-X-C chemokine receptor type 4 (CXCR4), the receptor for stromal cell-derived factor 1α (SDF-1α), in mediating oxidative stress-induced podocyte injury. In mouse model of adriamycin nephropathy (ADR), CXCR4 expression was significantly induced in podocytes as early as 3 days. This was accompanied by an increased upregulation of oxidative stress in podocyte, as demonstrated by malondialdehyde assay, nitrotyrosine staining and secretion of 8-hydroxy-2'-deoxyguanosine in urine, and induction of NOX2 and NOX4, major subunits of NADPH oxidase. CXCR4 was also induced in human kidney biopsies with proteinuric kidney diseases and colocalized with advanced oxidation protein products (AOPPs), an established oxidative stress trigger. Using cultured podocytes and mouse model, we found that AOPPs induced significant loss of podocyte marker Wilms tumor 1 (WT1), nephrin, and podocalyxin, accompanied by upregulation of desmin both in vitro and in vivo. Furthermore, AOPPs worsened proteinuria and aggravated glomerulosclerosis in ADR. These effects were associated with marked activation of SDF-1α/CXCR4 axis in podocytes. Administration of AMD3100, a specific inhibitor of CXCR4, reduced proteinuria and ameliorated podocyte dysfunction and renal fibrosis triggered by AOPPs in mice. In glomerular miniorgan culture, AOPPs also induced CXCR4 expression and downregulated nephrin and WT1. Innovation and Conclusion: These results suggest that chemokine receptor CXCR4 plays a crucial role in mediating oxidative stress-induced podocyte injury, proteinuria, and renal fibrosis. CXCR4 could be a new target for mitigating podocyte injury, proteinuria, and glomerular sclerosis in proteinuric chronic kidney disease. Antioxid. Redox Signal. 27, 345-362.

Anti-cancer properties of olive oil secoiridoid phenols: a systematic review of in vivo studies.

Epidemiological studies suggest that olive oil intake is associated to a reduced risk of cancer. Recently, the chemopreventive activity of olive oil has been attributed to its unique phenolic compounds represented by phenolic alcohols, hydroxytyrosol (3,4-dihydroxyphenylethanol: 3,4-DHPEA) and tyrosol (p-hydroxyphenylethanol: p-HPEA), and their secoiridoid derivatives 3,4-DHPEA-EA (oleuropein aglycon), p-HPEA-EA (ligstroside aglycon), 3,4-DHPEA-EDA, p-HPEA-EDA (oleocanthal), and oleuropein. Several studies have demonstrated that these compounds are able to inhibit proliferation and induce apoptosis in different tumor cell lines. These in vitro effects have been recently summarized in several reviews. The aim of this systematic review was to evaluate the in vivo anti-cancer activities of secoiridoid phenols as evidenced by either animal models of carcinogenesis or human intervention trials. From the literature research through "PubMed" and "Web of Science", 16 animal studies and 5 human intervention trials were identified and included in the review. Most of the animal studies have confirmed the ability of these compounds to inhibit the carcinogenesis process at both initiation and promotion/progression phases. All human intervention trials have investigated the effects of olive oil phenols on DNA damage. Among the five selected studies, three have shown a significant preventive effect on oxidative DNA damage in terms of reduction of 8-oxo-7,8-dihydro-2'-deoxyguanosine in urine, in mitochondria DNA of mononuclear cells and in lymphocyte DNA. The other two studies failed to see an effect on the urinary excretion of either etheno-DNA adducts or oxidation products of guanine. Further investigations are necessary to clarify the real chemopreventive potential of olive oil secoiridoid phenols on humans performing intervention studies on populations at high cancer risk.

Effect of inhaled N-acetylcysteine monotherapy on lung function and redox balance in idiopathic pulmonary fibrosis.

An oxidant-antioxidant imbalance is considered to be involved in the pathogenesis of idiopathic pulmonary fibrosis (IPF). Therefore, administration of antioxidants, such as N-acetylcysteine (NAC), may represent a potential treatment option for IPF patients. The aim of this study was to evaluate the effect of inhaled NAC monotherapy on lung function and redox balance in patients with IPF. A retrospective observational study was done, involving 22 patients with untreated early IPF (19 men; mean [±S.D.] age, 71.8 [±6.3]y). At baseline and at 6 and 12 months after initiating inhaled NAC monotherapy, we assessed forced vital capacity (FVC) and measured the levels of total glutathione, oxidized glutathione (GSSG), and the ratio of reduced to oxidized glutathione in whole blood (hereafter referred to as the ratio), and of 8-hydroxy-2'-deoxyguanosine in urine. To evaluate response to treatment, we defined disease progression as a decrease in FVC of ≥5% from baseline and stable disease as a decrease in FVC of <5%, over a period of 6 months. Change in FVC in the stable group at 6 and 12 months were 95±170mL and -70±120mL, while those in the progressive group at 6 and 12 months were -210±80mL, -320±350mL, respectively. The serial mean change in GSSG from baseline decreased as the ratio of reduced to oxidized glutathione increased in patients with stable disease, while it increased as this ratio decreased in patients with progressive disease. Receiver operating characteristic curve analysis revealed that a baseline GSSG level of ≥1.579μM was optimal for identifying treatment responders. Inhaled NAC monotherapy was associated with improved redox imbalance in patients with early IPF.

A novel DPP-4 inhibitor teneligliptin scavenges hydroxyl radicals: In vitro study evaluated by electron spin resonance spectroscopy and in vivo study using DPP-4 deficient rats

AimsRecently various dipeptidyl peptidase-4 (DPP-4) inhibitors have emerged because of their high effectiveness and safety. In spite of their common effect of DPP-4 inhibition, the chemical structures are diverse. Here we show that the structure of teneligliptin, a novel DPP-4 inhibitor, has a scavenging activity on hydroxyl radical (·OH). Methods·OH and superoxide (O2−) were detected by electron spin resonance (ESR) spectroscopy. ·OH and O2− were generated in vitro by the Fenton reaction and a hypoxanthine-xanthine oxidase system, respectively. The level of free radicals was estimated from the ESR signal intensity. The product via teneligliptin and ·OH reaction was identified by thin layer chromatography and mass spectrometry analysis. In vivo effect was also evaluated using DPP-4 deficient rats with streptozotocin-induced diabetes. ResultsESR spectroscopy analysis showed that teneligliptin did not scavenge O2−, but scavenged ·OH in a dose dependent manner. Its activity was greater than that of glutathione. The reaction product appeared to have an oxygen-atom added structure to that of teneligliptin, which was identical to the most abundant metabolite of teneligliptin in human plasma. Furthermore, using DPP-4 deficient rat, teneligliptin did not affect plasma glucose levels or body weight, but normalized increased levels of 8-hydroxy-2′-deoxyguanosine in urine, kidney and aorta of diabetic rats, supporting that teneligliptin may have a ·OH scavenging activity in vivo independently of DPP-4 inhibition. ConclusionsTeneligliptin is not only effective as DPP-4 inhibitor, but may also be beneficial as ·OH scavenger, which may be useful in the prevention of diabetic complications.

Effects of Silodosin, a Selective α1A-Adrenoceptor Antagonist, on Bladder Blood Flow and Bladder Function in a Rat Model of Atherosclerosis Induced Chronic Bladder Ischemia without Bladder Outlet Obstruction

We investigated the effects of the selective α1A-adrenoceptor antagonist silodosin on bladder blood flow and bladder function in a rat model of atherosclerosis induced chronic bladder ischemia without bladder outlet obstruction. The chronic bladder ischemia model was prepared by creating balloon endothelial injury of the bilateral iliac arteries in male rats. Using an osmotic pump, chronic bladder ischemia rats received silodosin subcutaneously at a rate of 0.1 or 0.3 mg/kg per day, or vehicle for 8 weeks. All groups received a 2% cholesterol diet throughout the experiment. For each α1-adrenoceptor subtype mRNA expression in bladder microvessels was examined by in situ hybridization. Bladder blood flow was measured using a laser speckle blood flow imager. Malondialdehyde in bladder tissue and 8-hydroxy-2'-deoxyguanosine in urine were measured as markers of oxidative stress. A metabolic cage study and cystometry were performed in conscious rats. The expression of all α1-adrenoceptor subtype mRNA was observed in rat bladder microvessels. Silodosin abrogated the decreased bladder blood flow in the empty bladder and during bladder distention that were evident in rats with chronic bladder ischemia. Levels of oxidative stress markers in these rats were significantly decreased by silodosin administration. Silodosin ameliorated bladder dysfunction in rats with chronic bladder ischemia in the metabolic cage study and on cystometry. Results suggest that in ischemic conditions α1-adrenoceptor antagonists such as silodosin may improve bladder function by restoring bladder blood flow.

A highly sensitive automated flow immunosensor based on kinetic exclusion analysis for determination of the cancer marker 8-hydroxy-2′-deoxyguanosine in urine

A highly sensitive automated flow immunosensor has been developed and validated for the measurement of the cancer marker 8-hydroxy-2′-deoxyguanosine (8-OHdG) in urine. The sensor employed the kinetic-exclusion analytical technology using the KinExA™ 3200 instrument. Various concentrations of 8-OHdG were incubated with a fixed amount of mouse anti-8-OHdG monoclonal antibody until the binding reaction reached equilibrium. These solutions were then passed rapidly over a bovine serum albumin conjugate of 8-hydroxyguanosine (8-OHG–BSA) coated onto polymethylmethacrylate beads contained in the observation cell of the KinExA instrument. The free anti-8-OHdG antibody was bound to the immobilized 8-OHG–BSA, however the unbound reagents were removed from the beads bed by flushing the system with phosphate-buffered saline. Fluorescent-labeled secondary antibody was passed rapidly over the beads bed, and the fluorescence was recorded during the flow of the secondary antibody through the beads. A calibration curve was generated by plotting the fluorescence signals that were retained on the beads as a function of 8-OHdG concentrations. The assay limit of detection was 0.05 ng ml−1 and the working range of the assay was 0.05–5 ng ml−1. The analytical recovery of urine-spiked 8-OHdG was 96.05–106.55 ± 3.00–6.40%. The precision of the sensor was satisfactory; relative standard deviation values were 3.28–4.89 and 4.40–6.89% for the intra- and inter-assay precision, respectively. The analytical performance of the proposed sensor was found to be superior to the conventional enzyme-linked immunosorbent assay for 8-OHdG. The proposed sensor is anticipated to have a great value in measurement of 8-OHdG where a more confident result is needed.

Ferulsinaic Acid Modulates SOD, GSH, and Antioxidant Enzymes in Diabetic Kidney.

The efficacy of Ferulsinaic acid (FA) to modulate the antioxidant enzymes and to reduce oxidative stress induced-diabetic nephropathy (DN) was studied. Rats were fed diets enriched with sucrose (50%, wt/wt), lard (30%, wt/wt), and cholesterol (2.5%, wt/wt) for 8 weeks to induce insulin resistance. After a DN model was induced by streptozotocin; 5, 50 and 500 mg/kg of FA were administrated by oral intragastric intubation for 12 weeks. In FA-treated diabetic rats, glucose, kidney/body weight ratio, creatinine, BUN, albuminurea, and creatinine clearance were significantly decreased compared with non treated diabetic rats. Diabetic rats showed decreased activities of SOD and GSH; increased concentrations of malondialdehyde and IL-6 in the serum and kidney, and increased levels of 8-hydroxy-2′-deoxyguanosine in urine and renal cortex. FA-treatment restored the altered parameters in a dose-dependent manner. The ultra morphologic abnormalities in the kidney of diabetic rats were markedly ameliorated by FA treatment. Furthermore, FA acid was found to attenuate chronic inflammation induced by both Carrageenan and dextran in rats. We conclude that FA confers protection against injuries in the kidneys of diabetic rats by increasing activities of antioxidant enzymes and inhibiting accumulation of oxidized DNA in the kidney, suggesting a potential drug for the prevention and therapy of DN.

A system consisting of cation‐exchange chromatography, combined surface‐activated chemical and electrospray ionization, and ion‐trap analysis for the analysis of 8‐oxo‐7,8‐dihydro‐2'‐deoxyguanosine in urine

8-Hydroxy-2'-deoxyguanosine has served as a biomarker for oxidative damage to DNA from different types of biological samples, and various techniques have been used to analyze it. In particular, liquid chromatography coupled to mass spectrometry has been used to identify 8-hydroxy-2'-deoxyguanosine in urine samples. Usually, a triple quadrupole analyzer and multiple reaction monitoring have been employed for its detection. Only a few studies have used a less expensive ion-trap analyzer instead. We have developed a new liquid chromatography/mass spectrometry procedure that incorporates cation-exchange chromatography in conjunction with surface-activated and electrospray ionization with an ion trap analyzer for the mass spectral step. The combination of two ionization sources reduced the matrix effect arising from in-source reactions, thus increasing the sensitivity to levels comparable with those obtained by triple quadrupole analyzers. This new method for 8-hydroxy-2'-deoxyguanosine detection provided increased sensitivity and reduced chemical noise, using a less expensive, stable and accurate mass spectrometric technology.

Microfluidic tool based on the antibody‐modified paramagnetic particles for detection of 8‐hydroxy‐2′‐deoxyguanosine in urine of prostate cancer patients

Guanosine derivatives are important for diagnosis of oxidative DNA damage including 8-hydroxy-2'-deoxyguanosine (8-OHdG) as one of the most abundant products of DNA oxidation. This compound is commonly determined in urine, which makes 8-OHdG a good non-invasive marker of oxidation stress. In this study, we optimized and tested the isolation of 8-OHdG from biological matrix by using paramagnetic particles with an antibody-modified surface. 8-OHdG was determined using 1-naphthol generated by alkaline phosphatase conjugated with the secondary antibody. 1-Naphthol was determined by stopped flow injection analysis (SFIA) with electrochemical detector using a glassy carbon working electrode and by stationary electrochemical detection using linear sweep voltammetry. A special modular electrochemical SFIA system which needs only 10 μL of sample including working buffer for one analysis was completely designed and successfully verified. The recoveries in different matrices and analyte concentration were estimated. Detection limit (3 S/N) was estimated as 5 pg/mL of 8-OHdG. This method promises to be very easily modified to microfluidic systems as "lab on valve". The optimized method had sufficient selectivity and thus could be used for determination of 8-OHDG in human urine and therefore for estimation of oxidative DNA damage as a result of oxidation stress in prostate cancer patients.

Trigonella foenum graecum seed extract protects kidney function and morphology in diabetic rats via its antioxidant activity

Oxidative stress is involved in the development and progression of diabetic nephropathy (DN). Because Trigonella foenum graecum has been reported to have antidiabetic and antioxidative effects, we hypothesized that T foenum graecum seed aqueous extract (TE) restores the kidney function of diabetic rats via its antioxidant activity. Rats were fed diets enriched with sucrose (50%, wt/wt), lard (30%, wt/wt), and cholesterol (2.5%, wt/wt) for 8 weeks to induce insulin resistance. After a DN model was induced by streptozotocin, the rats were administered a low (440 mg/kg), medium (870 mg/kg), or high (1740 mg/kg) dose of TE by oral intragastric intubation for 6 weeks. In TE-treated DN rats, blood glucose, kidney/body weight ratio, serum creatinine, blood urea nitrogen, 24-hour content of urinary protein, and creatinine clearance were significantly decreased compared with nontreated DN rats. Diabetic rats showed decreased activities of superoxide dismutase and catalase, increased concentrations of malondialdehyde in the serum and kidney, and increased levels of 8-hydroxy-2'-deoxyguanosine in urine and renal cortex DNA. Treatment with TE restored the altered parameters in a dose-dependent manner. Furthermore, all of the ultramorphologic abnormalities in the kidney of diabetic rats, including the uneven thickening of the glomerular base membrane, were markedly ameliorated by TE treatment. We conclude that TE confers protection against functional and morphologic injuries in the kidneys of diabetic rats by increasing activities of antioxidants and inhibiting accumulation of oxidized DNA in the kidney, suggesting a potential drug for the prevention and therapy of DN.

Correlation between concentrations of 8-oxo-7,8-dihydro-2′-deoxyguanosine in urine, plasma and saliva measured by on-line solid-phase extraction LC-MS/MS

Background 8-Oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodGuo) is the most frequently measured biomarker of oxidative stress. Chromatographic-based methods for 8-oxodGuo in urine are well established; however, the 8-oxodGuo measurement in plasma and saliva has been problematic. Methods We firstly and successfully applied an on-line solid-phase extraction (SPE) LC-MS/MS following manual SPE pretreatment to quantify the 8-oxodGuo both in plasma and saliva. Urine, plasma and saliva specimens were simultaneously collected from 50 healthy adults and measured for 8-oxodGuo. Results Mean baseline levels of 8-oxodGuo in plasma and saliva were 21.7 ± 9.2 and 5.1 ± 2.6 pg/ml, respectively, being far lower than that in urine (6.2 ± 4.8 ng/ml). The 8-oxodGuo levels obtained in this study for plasma and saliva were, however, up to several hundred times lower than those reported by commercial ELISA kit in the literature. Furthermore, the 8-oxodGuo levels in plasma and saliva were significantly correlated with the 8-oxodGuo levels in urine (Spearman correlation coefficients, r = 0.33, P = 0.02 for plasma and r = 0.56, P = 0.0015 for saliva). 8-OxodGuo in plasma was also correlated with the 8-oxodGuo in saliva ( r = 0.52, P = 0.0041). Conclusions Significantly correlations were observed between plasma, saliva and urine, giving the possibility of using other body fluids in addition to urine for assessing whole body oxidative stress.