Urinary 8-hydroxy-2 -deoxyguanosine(8-OHdG) is an excellent marker of oxidative DNA damage.In this study,employing guanosine as dummy template a novel molecularly imprinted(MIP) monolithic capillary column had been sy...Urinary 8-hydroxy-2 -deoxyguanosine(8-OHdG) is an excellent marker of oxidative DNA damage.In this study,employing guanosine as dummy template a novel molecularly imprinted(MIP) monolithic capillary column had been synthesized,and that was used as medium of in-tube solid phase microextraction(SPME).Coupled with capillary electrophoresis-electrochemical detection(CE-ECD),the system of extraction and detection of 8-OHdG in urinary sample had been developed.Because of its greater phase ratio combined with conv...展开更多
Reactive oxygen species may be involved in the progression of gastric carcinomas. To clarify whether the pathology of gastric carcinoma are related to oxidative DNA damage, the expression of 8-hydroxy-2＇-deoxyguanosi...Reactive oxygen species may be involved in the progression of gastric carcinomas. To clarify whether the pathology of gastric carcinoma are related to oxidative DNA damage, the expression of 8-hydroxy-2＇-deoxyguanosine （8-OHdG） was examined in 30 patients with gastric carcinomas. Methods： The expression of 8-OHdG and apoptosis in the gastric carcinoma were measured using the methods of immunocytochemistry and deoxynucleartididyl transferase-mediated dUTP-biotin nick end labeling （TUNEL）, respectively. Results： Of the 30 cases, 25（83%） showed stronger immunoreactivity than normal control. The patients with poorly differentiated gastric carcinoma had a larger tumor size and higher labeling indices of TUNEL- and 8-OHdG-positive cells than those with well and moderately differentiated gastric carcinoma. Conclusion： Our findings suggest that oxidative DNA damage is increased in association with necroinflammation in chronic gastric injuries and determination of 8-OHdG is useful in assessing high-grade malignancy in gastric carcinomas.展开更多
8-hydroxy-2’-deoxyguanosine (8-OHdG), a typical form ofDNA adducts, is a key molecular biomarker for DNA oxidativedamage. The aim of the present study was to evaluote the correla-tion between the sperm DNA 8-OHdG lev...8-hydroxy-2’-deoxyguanosine (8-OHdG), a typical form ofDNA adducts, is a key molecular biomarker for DNA oxidativedamage. The aim of the present study was to evaluote the correla-tion between the sperm DNA 8-OHdG level and the semen quality.In 52 male infertile patients, the sperm DNA 8-OHdG level wasdetermined by a high performance liquid chromatograph with elec-trochemical detector and the semen quality was examined according展开更多
8-Oxoguanine （8-oxoG）, a critical mutagenic DNA lesion induced by reactive oxy- gen species, gives rise to a G·C→T·A transversion during replication and thereby must be repaired. The effects of explicit a...8-Oxoguanine （8-oxoG）, a critical mutagenic DNA lesion induced by reactive oxy- gen species, gives rise to a G·C→T·A transversion during replication and thereby must be repaired. The effects of explicit and implicit solvent molecules on the hydrolysis cleavage of N-Glycosidic bond in 8-oxo-7,8-dihydro-2＇-deoxyguanosine （8-oxo-dG） have been systematically clarified in the present work based upon two types of computational models. Detailed potential energy surface （PES） scans and full unconstraint optimizations for all the representative points on PESs were carried out at the B3LYP/6-31＋G（d） level of theory. The effect of implicit solvent was tested by single-point calculation at the SCRF/IEF-PCM model. The results illustrate that the direct hydrolysis model involving one explicit water molecule can’t provide a complete depiction of the hydrolysis process of 8-oxo-dG, attributed to the insufficiency of nucleophile activation and leaving group stabilization. The expansion hydrolysis model involving four explicit water molecules, however, facilitates discrete proton transfer and therefore produces smooth reaction surfaces for both the dissociative （SN1） and concerted （SN2） pathways. The presence of the implicit solvent substantially lowers all activation energies and the SN1 process is more favorable than the SN2 process. The data and insights present here agree well with the experimental results and have given out a baseline for the enzymatic deglycosylation reaction of 8-oxo-dG.展开更多
Previous studies have reported a neuroprotective effect of 8-hydroxy-2-（di-n-propylamino）tetralin （8-OH-DPAT） against traumatic brain injury. In accordance with the Marmarou method, rat models of diffuse axonal in...Previous studies have reported a neuroprotective effect of 8-hydroxy-2-（di-n-propylamino）tetralin （8-OH-DPAT） against traumatic brain injury. In accordance with the Marmarou method, rat models of diffuse axonal injury were established. 8-OH-DPAT was intraperitoneally injected into model rats. 8-OH-DPAT treated rats maintained at constant temperature served as normal temperature controls TUNEL results revealed that neural cell swelling, brain tissue necrosis and cell apoptosis occurred around the injured tissue. Moreover, the number of Bax-, Bcl-2- and caspase-3-positive cells increased at 6 hours after diffuse axonal injury, and peaked at 24 hours. However, brain injury was attenuated, the number of apoptotic cells reduced, Bax and caspase-3 expression decreased, and Bcl-2 expression increased at 6, 12, 24, 72 and 168 hours after diffuse axonal injury in normal temperature control and in 8-OH-DPAT-intervention rats. The difference was most significant at 24 hours. All indices in 8-OH-DPAT-intervention rats were better than those in the constant temperature group. These results suggest that 8-OH-DPAT inhibits Bax and caspase-3 expression, increases Bcl-2 expression, and reduces neural cell apoptosis, resulting in neuroprotection against diffuse axonal injury. This effect is associated with a decrease in brain temperature.展开更多
Background: Oxidative stress has been closely linked to the incidence of diabetic complications. Therefore, the aim of this research article was to study hyperglycemia and abnormal lipid profile in diabetic patient ty...Background: Oxidative stress has been closely linked to the incidence of diabetic complications. Therefore, the aim of this research article was to study hyperglycemia and abnormal lipid profile in diabetic patient type 2 and its correlation with oxidative stress development as measured by 8-iso-PGF2α and 8-OHdG. Methods: Fifty (50) patients confirmed type 2 diabetes mellitus and eighty (80) non-diabetic control individuals were included in this study. All individuals were tested for blood glucose, lipid profile, 8-iso-PGF2α and 8-OHdG HdG. Results: The age of diabetic patients was observed to be ≥40 yrs in 96% and diabetes was frequently detected in female than in male patients (76% vs. 24%, p ere elevated in diabetic patients compared with control individuals (p < 0.0001) except in HDL-C, a significant decrease was recorded (p = 0.04). Serum 8-iso-PGF2α and 8-OHdG were elevated significantly in diabetic patients compared with non-diabetic control and a significant correlation was recorded between them (r = 0.6, p α was associated with Age (r = 0.394, p < 0.0001), FBG (0.553, p < 0.0001), LDL-C (r = 0.2, p = 0.023), TG (r = 0.176, p = 0.045) and TC (r = 0.2, p = 0.02). Also, 8-OHdG was associated with age (r = 0.558, p < 0.0001), FBG (r = 0.67, p < 0.0001), LDL-C (r = 0.28, p = 0.001), TG (r = 0.358, p < 0.0001) and TC (r = 0.33, p < 0.0001). Age, FBG, HbA1c, LDL-C, TG and TC showed a significant linear regression with 8-iso-PGF2α and 8-OHdG recording its role as significant predictors for the elevation of 8-iso-PGF2α and 8-OHdG. Therefore, hyperglycemia with oxidative stress development may play a role for dyslipidemia and diabetic complications. Conclusion: Diabetic patient’s type 2 has a higher rate of abnormal serum lipids and correlates significantly with lipid peroxidation and oxidized DNA bases as measured by 8-iso-PGF2α and 8-OHdG. Therefore, 8-iso-PGF2α and 8-OHdG could be used as oxidative biomarkers for evaluating diabetic patients with early prediction of its complications and cancer development.展开更多
A composite film of DNA/poly(3-methylthiophene)(P3MT) modified glassy carbon electrode(GCE) has been fabricated by electro-deposition method.P3MT film was first electropolymerized at the GCE and the DNA layer was then...A composite film of DNA/poly(3-methylthiophene)(P3MT) modified glassy carbon electrode(GCE) has been fabricated by electro-deposition method.P3MT film was first electropolymerized at the GCE and the DNA layer was then immobilized on the P3MT layer by electrochemical method.The voltammetric behavior of 8-hydroxy-2'-deoxyguanosine(8-OH-dG) at the composite film modified electrode was studied.The effects of scan rates,pH and the interference of uric acid(UA) on the voltammetric behavior and detection of 8-OH-dG were also discussed.The experimental results suggest that the electrochemical behavior of 8-OH-dG at the composite film modified electrode was greatly improved due to the combination of the advantages of P3MT and DNA.In 0.1 M pH 7.0 phosphate buffer solution(PBS),the anodic peak currents of 8-OH-dG were linear with the 8-OH-dG concentration in two intervals,viz.0.28―4.2 μM and 4.2―19.6 μM.The detection limit of 56 nM 8-OH-dG could be estimated(S/N=3).This proposed composite film modified electrode shows excellent reproducibility and stability.It may have the potential application for the detection of 8-OH-dG in human urine.展开更多
Halobenzoquinones（HBQs） are an emerging class of halogenated disinfection byproducts（DBPs） in drinking water, which raised public concerns due to potential carcinogenic effects to human bladder. Our previous work ...Halobenzoquinones（HBQs） are an emerging class of halogenated disinfection byproducts（DBPs） in drinking water, which raised public concerns due to potential carcinogenic effects to human bladder. Our previous work demonstrated that HBQs and hydrogen peroxide（H_2O_2）together generated oxidative DNA damage via a metal-independent and intercalationenhanced oxidation mechanism in vitro. This study further investigated the efficiency of various HBQs to induce oxidative DNA damage in T24 bladder cancer cells. Compared with T24 cells without treatment（3.1 lesions per 10~6 d G）, the level of 8-oxo-7,8-dihydro-2′-deoxyguanosine（8-oxod G） significantly increased by 1.4, 3.2, 8.8, and 9.2 times after treatment with tetrabromo-1,4-benzoquinone（TBBQ）, terachloro-1,4-benzoquinone（TCBQ）,2,6-dichloro-1,4-benzoquinone（2,6-DCBQ） and 2,5-dichloro-1,4-benzoquinone（2,5-DCBQ） for24 hr, respectively. Interestingly, we found that the oxidative potency of HBQs in T24 cells（2,5-DCBQ ≈ 2,6-DCBQ 〉 TCBQ 〉 TBBQ） is inconsistent with that of in vitro ds DNA oxidation（TCBQ 〉 TBBQ 〉 2,5-DCBQ 〉 2,6-DCBQ）, suggesting HBQs induce oxidative lesions in cellular genomic DNA probably involved with a complex mechanism.展开更多
To observe the alteration in the expression of DNA repair enzymes hOGG1 and hMYHa and the change in 8-OHdG levels in the HBx gene-transfected cells HepG2/HBx and to explore the mechanisms of the HBV-associated hepatoc...To observe the alteration in the expression of DNA repair enzymes hOGG1 and hMYHa and the change in 8-OHdG levels in the HBx gene-transfected cells HepG2/HBx and to explore the mechanisms of the HBV-associated hepatocellular carcinoma, the gene-transfected cells HepG2/HBx which stably expressed HBx was established, and the effect of HBx on the cell cycle and proliferation of HepG2 was examined. By using the β-actin as the interior control, real-time polymerase chain reaction （Real-time qPCR） was employed to quantitatively detect the expression of DNA repair enzymes hOGG1 and hMYHα in the HepG2/HBx, the control cells HepG2 and HepG2 transfected with pcDNA3.1 vector （HepG2/pDNA3.1）. The 8-OHdG levels were determined by HPLC/ECD in the established gene-transfected cells HepG2/HBx and the control cells HepG2 and HepG2/pcDNA3.1. Our results showed that the expression of DNA repair enzyme hMYHα in the HepG2/HBx （0.021±0.007） was significantly lower than that of HepG2 （0.099±0.041） （P〈0.05） and HepG2/pDNA3.1 （0.121±0.005） （P〈0.05）. However, the no significant differences existed in the expression of DNA repair enzyme hOGG1 among the three cell strains （P〉0.05）. The 8-OHdG level in the HepG2/HBx was significantly higher than that in HepG2 and HepG2/pcDNA3.1 （P〈0.05）. It is concluded that HBx gene may inhibit the expression of DNA repair enzyme hMYHα mRNA to impair the ability to repair the intracellular DNA oxidative damage, to increase the oxidative DNA-adduct 8-OHdG and to affect the nucleotide excision repair function, thus participate in the occurrence and development of hepatocellular carcinoma.展开更多
4,4’-Methylenebis(2-chloroaniline) (MBOCA) is a probable human carcinogen. Few studies have been performed regarding the genotoxicity of MBCOA, and the MBOCA metabolic pathway is not fully understood. We treated four...4,4’-Methylenebis(2-chloroaniline) (MBOCA) is a probable human carcinogen. Few studies have been performed regarding the genotoxicity of MBCOA, and the MBOCA metabolic pathway is not fully understood. We treated four-week-old ICR male mice weighing 25 - 30 g with MBOCA and observed the effects of MBOCA on the internal organs. It can be concluded that MBOCA is a carcinogen and also affects gene regulation. Oral or topical administration of 50 mg/kg, 100 mg/kg or 200 mg/kg MBOCA resulted in 56% - 81% of mice showing unusual inflammation, degeneration, and dysplasia in kidney, liver, stomach, intestine and urinary bladder based on histology. Furthermore, we investigated the association between oxidative DNA damage and MBOCA exposure by measuring plasma level of 8-hydroxydeoxyguanosine (8-OHdG). The results showed that the MBOCA-treated mice had significantly higher 8-OHdG levels than the control mice. This study confirms that MBOCA is potentially carcinogenic and highly toxic to both animals and humans.展开更多
Oxidative stress may be the unifying factor for the injury caused by hyperglycemia in diabetic peripheral neuropathy. Puerarin is the major isoflavonoid derived from Radix puerariae and has been shown to be effective ...Oxidative stress may be the unifying factor for the injury caused by hyperglycemia in diabetic peripheral neuropathy. Puerarin is the major isoflavonoid derived from Radix puerariae and has been shown to be effective in increasing superoxide dismutase activity. This study sought to investigate the neuroprotective effect of puerarin on high glucose-induced oxidative stress and Schwann cell apoptosis in vitro. Intracellular reactive oxygen radicals and mitochondrial transmembrane potential were detected by flow cytometry analysis. Apoptosis was confirmed by TUNEL and oxidative stress was monitored using an enzyme-linked immunosorbent assay for the DNA marker 8-hydroxy-2-deoxyguanosine. The expression levels of bax and bcl-2 were analyzed by quantitative real-time reverse transcriptase-PCR, while protein expression of cleaved caspase-3 and -9 were analyzed by means of western blotting. Results suggested that puerarin treatment inhibited high glucose-induced oxidative stress, mitochondrial depolarization and apoptosis in a dose-dependent manner. Furthermore, puerarin treatment downregulated Bax expression, upregulated bcl-2 expression and attenuated the activation of caspase-3 and -9. Overall, our results indicated that puerarin antagonized high glucose-induced oxidative stress and apoptosis in Schwann cells.展开更多
基金the support of the National Natural Science Foundation of China(No.20575051).
文摘Urinary 8-hydroxy-2 -deoxyguanosine(8-OHdG) is an excellent marker of oxidative DNA damage.In this study,employing guanosine as dummy template a novel molecularly imprinted(MIP) monolithic capillary column had been synthesized,and that was used as medium of in-tube solid phase microextraction(SPME).Coupled with capillary electrophoresis-electrochemical detection(CE-ECD),the system of extraction and detection of 8-OHdG in urinary sample had been developed.Because of its greater phase ratio combined with conv...
基金Nature Science Fundation of Jiangsu Province (BK2004146)Science Fund of Department of Education of Jiangsu Province (03KJB310085)
文摘Reactive oxygen species may be involved in the progression of gastric carcinomas. To clarify whether the pathology of gastric carcinoma are related to oxidative DNA damage, the expression of 8-hydroxy-2＇-deoxyguanosine （8-OHdG） was examined in 30 patients with gastric carcinomas. Methods： The expression of 8-OHdG and apoptosis in the gastric carcinoma were measured using the methods of immunocytochemistry and deoxynucleartididyl transferase-mediated dUTP-biotin nick end labeling （TUNEL）, respectively. Results： Of the 30 cases, 25（83%） showed stronger immunoreactivity than normal control. The patients with poorly differentiated gastric carcinoma had a larger tumor size and higher labeling indices of TUNEL- and 8-OHdG-positive cells than those with well and moderately differentiated gastric carcinoma. Conclusion： Our findings suggest that oxidative DNA damage is increased in association with necroinflammation in chronic gastric injuries and determination of 8-OHdG is useful in assessing high-grade malignancy in gastric carcinomas.
文摘8-hydroxy-2’-deoxyguanosine (8-OHdG), a typical form ofDNA adducts, is a key molecular biomarker for DNA oxidativedamage. The aim of the present study was to evaluote the correla-tion between the sperm DNA 8-OHdG level and the semen quality.In 52 male infertile patients, the sperm DNA 8-OHdG level wasdetermined by a high performance liquid chromatograph with elec-trochemical detector and the semen quality was examined according
基金supported by the National Natural Science Foundation of China(21203153 and 21173151)Science&Technology Department(2011JY0136)+1 种基金Department of Education(12ZA174)of Sichuan ProvinceChina West Normal University(11B002)
文摘8-Oxoguanine （8-oxoG）, a critical mutagenic DNA lesion induced by reactive oxy- gen species, gives rise to a G·C→T·A transversion during replication and thereby must be repaired. The effects of explicit and implicit solvent molecules on the hydrolysis cleavage of N-Glycosidic bond in 8-oxo-7,8-dihydro-2＇-deoxyguanosine （8-oxo-dG） have been systematically clarified in the present work based upon two types of computational models. Detailed potential energy surface （PES） scans and full unconstraint optimizations for all the representative points on PESs were carried out at the B3LYP/6-31＋G（d） level of theory. The effect of implicit solvent was tested by single-point calculation at the SCRF/IEF-PCM model. The results illustrate that the direct hydrolysis model involving one explicit water molecule can’t provide a complete depiction of the hydrolysis process of 8-oxo-dG, attributed to the insufficiency of nucleophile activation and leaving group stabilization. The expansion hydrolysis model involving four explicit water molecules, however, facilitates discrete proton transfer and therefore produces smooth reaction surfaces for both the dissociative （SN1） and concerted （SN2） pathways. The presence of the implicit solvent substantially lowers all activation energies and the SN1 process is more favorable than the SN2 process. The data and insights present here agree well with the experimental results and have given out a baseline for the enzymatic deglycosylation reaction of 8-oxo-dG.
基金funded by the Natural Science Foundation of Technology Department of Liaoning Province, No.20032047
文摘Previous studies have reported a neuroprotective effect of 8-hydroxy-2-（di-n-propylamino）tetralin （8-OH-DPAT） against traumatic brain injury. In accordance with the Marmarou method, rat models of diffuse axonal injury were established. 8-OH-DPAT was intraperitoneally injected into model rats. 8-OH-DPAT treated rats maintained at constant temperature served as normal temperature controls TUNEL results revealed that neural cell swelling, brain tissue necrosis and cell apoptosis occurred around the injured tissue. Moreover, the number of Bax-, Bcl-2- and caspase-3-positive cells increased at 6 hours after diffuse axonal injury, and peaked at 24 hours. However, brain injury was attenuated, the number of apoptotic cells reduced, Bax and caspase-3 expression decreased, and Bcl-2 expression increased at 6, 12, 24, 72 and 168 hours after diffuse axonal injury in normal temperature control and in 8-OH-DPAT-intervention rats. The difference was most significant at 24 hours. All indices in 8-OH-DPAT-intervention rats were better than those in the constant temperature group. These results suggest that 8-OH-DPAT inhibits Bax and caspase-3 expression, increases Bcl-2 expression, and reduces neural cell apoptosis, resulting in neuroprotection against diffuse axonal injury. This effect is associated with a decrease in brain temperature.
文摘Background: Oxidative stress has been closely linked to the incidence of diabetic complications. Therefore, the aim of this research article was to study hyperglycemia and abnormal lipid profile in diabetic patient type 2 and its correlation with oxidative stress development as measured by 8-iso-PGF2α and 8-OHdG. Methods: Fifty (50) patients confirmed type 2 diabetes mellitus and eighty (80) non-diabetic control individuals were included in this study. All individuals were tested for blood glucose, lipid profile, 8-iso-PGF2α and 8-OHdG HdG. Results: The age of diabetic patients was observed to be ≥40 yrs in 96% and diabetes was frequently detected in female than in male patients (76% vs. 24%, p ere elevated in diabetic patients compared with control individuals (p < 0.0001) except in HDL-C, a significant decrease was recorded (p = 0.04). Serum 8-iso-PGF2α and 8-OHdG were elevated significantly in diabetic patients compared with non-diabetic control and a significant correlation was recorded between them (r = 0.6, p α was associated with Age (r = 0.394, p < 0.0001), FBG (0.553, p < 0.0001), LDL-C (r = 0.2, p = 0.023), TG (r = 0.176, p = 0.045) and TC (r = 0.2, p = 0.02). Also, 8-OHdG was associated with age (r = 0.558, p < 0.0001), FBG (r = 0.67, p < 0.0001), LDL-C (r = 0.28, p = 0.001), TG (r = 0.358, p < 0.0001) and TC (r = 0.33, p < 0.0001). Age, FBG, HbA1c, LDL-C, TG and TC showed a significant linear regression with 8-iso-PGF2α and 8-OHdG recording its role as significant predictors for the elevation of 8-iso-PGF2α and 8-OHdG. Therefore, hyperglycemia with oxidative stress development may play a role for dyslipidemia and diabetic complications. Conclusion: Diabetic patient’s type 2 has a higher rate of abnormal serum lipids and correlates significantly with lipid peroxidation and oxidized DNA bases as measured by 8-iso-PGF2α and 8-OHdG. Therefore, 8-iso-PGF2α and 8-OHdG could be used as oxidative biomarkers for evaluating diabetic patients with early prediction of its complications and cancer development.
基金Supported by the National Natural Science Foundation of China (Grant Nos. 20475024 & 20775031)the Shandong Tai-Shan Scholar Research Fund
文摘A composite film of DNA/poly(3-methylthiophene)(P3MT) modified glassy carbon electrode(GCE) has been fabricated by electro-deposition method.P3MT film was first electropolymerized at the GCE and the DNA layer was then immobilized on the P3MT layer by electrochemical method.The voltammetric behavior of 8-hydroxy-2'-deoxyguanosine(8-OH-dG) at the composite film modified electrode was studied.The effects of scan rates,pH and the interference of uric acid(UA) on the voltammetric behavior and detection of 8-OH-dG were also discussed.The experimental results suggest that the electrochemical behavior of 8-OH-dG at the composite film modified electrode was greatly improved due to the combination of the advantages of P3MT and DNA.In 0.1 M pH 7.0 phosphate buffer solution(PBS),the anodic peak currents of 8-OH-dG were linear with the 8-OH-dG concentration in two intervals,viz.0.28―4.2 μM and 4.2―19.6 μM.The detection limit of 56 nM 8-OH-dG could be estimated(S/N=3).This proposed composite film modified electrode shows excellent reproducibility and stability.It may have the potential application for the detection of 8-OH-dG in human urine.
基金supported by the Ministry of Science and Technology of China(Nos.2016YFA0203102,2016YFC0900301 and 2014CB932003)the National Natural Science Foundation of China(Nos.21375142,21321004,and 21435008)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB14030000)
文摘Halobenzoquinones（HBQs） are an emerging class of halogenated disinfection byproducts（DBPs） in drinking water, which raised public concerns due to potential carcinogenic effects to human bladder. Our previous work demonstrated that HBQs and hydrogen peroxide（H_2O_2）together generated oxidative DNA damage via a metal-independent and intercalationenhanced oxidation mechanism in vitro. This study further investigated the efficiency of various HBQs to induce oxidative DNA damage in T24 bladder cancer cells. Compared with T24 cells without treatment（3.1 lesions per 10~6 d G）, the level of 8-oxo-7,8-dihydro-2′-deoxyguanosine（8-oxod G） significantly increased by 1.4, 3.2, 8.8, and 9.2 times after treatment with tetrabromo-1,4-benzoquinone（TBBQ）, terachloro-1,4-benzoquinone（TCBQ）,2,6-dichloro-1,4-benzoquinone（2,6-DCBQ） and 2,5-dichloro-1,4-benzoquinone（2,5-DCBQ） for24 hr, respectively. Interestingly, we found that the oxidative potency of HBQs in T24 cells（2,5-DCBQ ≈ 2,6-DCBQ 〉 TCBQ 〉 TBBQ） is inconsistent with that of in vitro ds DNA oxidation（TCBQ 〉 TBBQ 〉 2,5-DCBQ 〉 2,6-DCBQ）, suggesting HBQs induce oxidative lesions in cellular genomic DNA probably involved with a complex mechanism.
基金supported by a grant from the National Natural Sciences Foundation of China (No.30570821)
文摘To observe the alteration in the expression of DNA repair enzymes hOGG1 and hMYHa and the change in 8-OHdG levels in the HBx gene-transfected cells HepG2/HBx and to explore the mechanisms of the HBV-associated hepatocellular carcinoma, the gene-transfected cells HepG2/HBx which stably expressed HBx was established, and the effect of HBx on the cell cycle and proliferation of HepG2 was examined. By using the β-actin as the interior control, real-time polymerase chain reaction （Real-time qPCR） was employed to quantitatively detect the expression of DNA repair enzymes hOGG1 and hMYHα in the HepG2/HBx, the control cells HepG2 and HepG2 transfected with pcDNA3.1 vector （HepG2/pDNA3.1）. The 8-OHdG levels were determined by HPLC/ECD in the established gene-transfected cells HepG2/HBx and the control cells HepG2 and HepG2/pcDNA3.1. Our results showed that the expression of DNA repair enzyme hMYHα in the HepG2/HBx （0.021±0.007） was significantly lower than that of HepG2 （0.099±0.041） （P〈0.05） and HepG2/pDNA3.1 （0.121±0.005） （P〈0.05）. However, the no significant differences existed in the expression of DNA repair enzyme hOGG1 among the three cell strains （P〉0.05）. The 8-OHdG level in the HepG2/HBx was significantly higher than that in HepG2 and HepG2/pcDNA3.1 （P〈0.05）. It is concluded that HBx gene may inhibit the expression of DNA repair enzyme hMYHα mRNA to impair the ability to repair the intracellular DNA oxidative damage, to increase the oxidative DNA-adduct 8-OHdG and to affect the nucleotide excision repair function, thus participate in the occurrence and development of hepatocellular carcinoma.
文摘4,4’-Methylenebis(2-chloroaniline) (MBOCA) is a probable human carcinogen. Few studies have been performed regarding the genotoxicity of MBCOA, and the MBOCA metabolic pathway is not fully understood. We treated four-week-old ICR male mice weighing 25 - 30 g with MBOCA and observed the effects of MBOCA on the internal organs. It can be concluded that MBOCA is a carcinogen and also affects gene regulation. Oral or topical administration of 50 mg/kg, 100 mg/kg or 200 mg/kg MBOCA resulted in 56% - 81% of mice showing unusual inflammation, degeneration, and dysplasia in kidney, liver, stomach, intestine and urinary bladder based on histology. Furthermore, we investigated the association between oxidative DNA damage and MBOCA exposure by measuring plasma level of 8-hydroxydeoxyguanosine (8-OHdG). The results showed that the MBOCA-treated mice had significantly higher 8-OHdG levels than the control mice. This study confirms that MBOCA is potentially carcinogenic and highly toxic to both animals and humans.
基金supported by the National Natural Science Foundation of China, No. 30973354
文摘Oxidative stress may be the unifying factor for the injury caused by hyperglycemia in diabetic peripheral neuropathy. Puerarin is the major isoflavonoid derived from Radix puerariae and has been shown to be effective in increasing superoxide dismutase activity. This study sought to investigate the neuroprotective effect of puerarin on high glucose-induced oxidative stress and Schwann cell apoptosis in vitro. Intracellular reactive oxygen radicals and mitochondrial transmembrane potential were detected by flow cytometry analysis. Apoptosis was confirmed by TUNEL and oxidative stress was monitored using an enzyme-linked immunosorbent assay for the DNA marker 8-hydroxy-2-deoxyguanosine. The expression levels of bax and bcl-2 were analyzed by quantitative real-time reverse transcriptase-PCR, while protein expression of cleaved caspase-3 and -9 were analyzed by means of western blotting. Results suggested that puerarin treatment inhibited high glucose-induced oxidative stress, mitochondrial depolarization and apoptosis in a dose-dependent manner. Furthermore, puerarin treatment downregulated Bax expression, upregulated bcl-2 expression and attenuated the activation of caspase-3 and -9. Overall, our results indicated that puerarin antagonized high glucose-induced oxidative stress and apoptosis in Schwann cells.
