Research Progress of DNA-Based Technologies for Postmortem Interval Estimation / 法医学杂志

In criminal investigations, postmortem interval (PMI) is important information to be inferred in homicide investigations, as well as the focus and the difficulty in forensic pathology research. Because the DNA content in different tissues is relatively constant and shows changes regularly with the extension of PMI, it has become a research hotspot of PMI estimation. This paper reviews the recent progress of PMI estimation technologies including DNA-based single cell gel electrophoresis, image analysis, flow cytometry, real-time fluorescence quantitative PCR and high-throughput sequencing, hoping to provide references for forensic medicine practice and scientific research.

Insight into DNA protection ability of medicinal herbs and potential mechanisms in hydrogen peroxide damages model

DNA damage is one of the most important consequences of oxidative stress in the cells. If DNA repair is unable to modify these inducible DNA damages, genomic instability may lead to mutation, cancer, aging and many other diseases. Single cell gel electrophoresis or comet assay is a common and versatile method to quantify these types of DNA damages. DNA damages induced by hydrogen peroxide (H

Insight into DNA protection ability of medicinal herbs and potential mechanisms in hydrogen peroxide damages model

DNA damage is one of the most important consequences of oxidative stress in the cells.If DNA repair is unable to modify these inducible DNA damages,genomic instability may lead to mutation,cancer,aging and many other diseases.Single cell gel electrophoresis or comet assay is a common and versatile method to quantify these types of DNA damages.DNA damages induced by hydrogen peroxide (H2O2) are one of the proper models for measurement of protective ability of different compounds.So the main aim of this review is to provide an overview about protection ability of medicinal plants and their potential mechanism against H2O2 induced DNA damages.In this review,relevant researches on the effect of medicinal plants on DNA damages induced by H2O2 and possible molecular mechanisms are discussed.It seems that,medicinal plants are considered as therapeutic key factors to protect DNA from consequences caused by oxidative stress.Sufficientin vitro evidences introduce them as DNA protective agents through different mechanisms including antioxidant activity and some other cellular mechanisms.Moreover,in order to correlate the antigenotoxicity effects with their potential antioxidant property,most of medicinal plants were evaluated in term of antioxidant activity using standard methods.This review highlights the preventive effects of herbal medicine against oxidative DNA damages as well as provides rational possibility to engage them in animal studies and future clinical investigations.

Comparison of 4 kinds of nucleic acid fluorescent dyes in single-cell gel electrophoresis assay / 临床检验杂志

Objective To investigate the DNA staining efficiencies of 4 kinds of nucleic acid fluorescent dyes,including EB,SYBR Green Ⅰ,Gold View and AO,in single-cell gel electrophoresis (SCGE) assay,and the possibility to use a new nucleic acid fluorescent dye instead of EB.Methods The peripheral blood lymphocytes from healthy individuals were isolated and treated with 0,20,40,60 and 80 μg/mL of H2O2,respectively.Then,the DNA damages of lymphocytes were detected by the neutral SCGE assay.The DNA was stained with EB,SYBR Green Ⅰ,Gold View and AO dyes,respectively,and the staining results were observed and compared under a fluorescence microscope.In addition,the percentages of tail DNA (％ Tail DNA) from different staining methods were analyzed and compared.Results The results of SCGE showed that SYBR Green Ⅰ,Gold View and AO staining could well reflect the DNA damages of lymphocytes,and that the optimal concentrations for SYBR Green Ⅰ,Gold View and AO were 1 ×-5 ×,2 ×-5 × and 2-5 μg/mL,respectively.The regression coefficients for EB,SYBR Green Ⅰ,Gold View and AO were 2.71,2.81,2.73 and 2.75,respectively,which indicated that there was consistent dyeing effect between them.The results of ％ Tail DNA were stable with in 48 hours,and there was no significant difference between the 4 fluoresent dyes (P ＞ O.05).The inter-assay coefficients of variation (CVs) of SYBR Green Ⅰ,Gold View and AO were 6.92％,7.10％ and 8.25％,respectively,which were superior to that of EB (8.35％).The intra-assay CVs of SYBR Green Ⅰ and Gold View were 3.07％ and 2.74％,respectively,which were superior to that of EB (3.59％).Conclusion SYBR Green Ⅰ,Gold View and AO may be used for the nucleic acid fluorescent staining,and especially Gold View is more suitable for instead of EB in SCGE.

DNA damages in mouse hepatocytes and lymphocytes induced by aniline and their repair dynamics / 中国实验动物学报

Objective To investigate the genotoxicity of aniline and repair dynamics in hepatocytes and lymph-cytes.Methods Aniline was administered intragastrically to SPF Kunming mice ( five mice in each group) in a single dose of 100 mg/kg body weight.The hepatocytes and peripheral blood lymphocytes were obtained at 3, 8, 16, 24, and 32 hours after aniline administration, respectively.The control mice received tap water only.The DNA damages were detected by single cell gel electrophoresis assay ( SCGE) and the time-effect relationship was analyzed.Results The results of SCGE experiment showed that both the tail lenth and tail moment of the hepatocyte DNA were increased gradually from 8 h, and reached the maximum at 16 h ( P0.05).The two DNA damage indexes of peripheral blood lymphocytes started to increase at 16 h, reached the maxi-mum at 24 h ( P<0.01) , and began to recover at 32 h after aniline administration.Conclusions Our findings suggeste that aniline may be a potential genotoxicant to hepatocytes and peripheral blood lymphocytes.There is a clear time-response relationship in terms of the two DNA damage indexes, indicating that hepatocytes and lymphocytes in mice possess an effi-cient DNA repair mechanism against aniline toxicity.

Study of ironizing radiation sensitivity decrease of stem cell induced by 635 nm low level laser / 国际生物医学工程杂志

Objective To study the radioresistance increased by low level laser irradiation (LLLI) in stem cells.Methods Umbilical cord mesenchymal stem cells (UC-MSCs) were divided into control group and experimental groups (LLLI only,γ-ray irradiation only and LLLI combined with γ-ray irradiation groups).635 nm (10 mW/cm2,12 J/cm2) laser irradiation was applied using for 3 days (twice a day),and cells were exposed in 2 Gy dose γ-ray irradiation on the third day.DNA injury was detected by alkaline single cell gel electrophoresis,reactive oxygen species (ROS),superoxide dismutase (SOD) and catalase (CAT) activity were valued using detection kits.Results DNA injury in LLLI combined with γ-ray irradiation group was lower than that in γ-ray irradiation exposed group,activity of oxidation stress kinases was enhanced,and level of ROS was inhibited.Conclusions Ironizing radioresistance of UC-MSCs can be increased after treatment of 635 nm LLLI,which will induce the radiation sensitivity of transplanting cells.

Assessing extent of single stranded DNA damage in oral mucosal cells of patients with oral squamous cell carcinoma and its correlation with TNM staging.

Context: This study was carried out on the assumption that oral mucosal cells might show DNA damage in oral squamous cell carcinoma (OSCC). Aims: To evaluate the extent of DNA damage in oral smears of patients with OSCC and determine correlation if any of the extent of DNA damage to TNM staging of oral cancer. Settings and design: A randomized controlled study at a regional cancer centre was designed for this project. Smears were taken from lesion proper of 30 patients with OSCC and from the buccal mucosa of 30 normal healthy volunteers. Materials and methods: Collected cells were centrifuged and single-cell gel electrophoresis (SCGE) assay was performed. DNA damage was visualized under a fluorescent microscope. Statistical analysis used : Mean DNA damage levels of both the groups were measured and statistically analyzed with students' test. The extent of DNA damage was correlated with the TNM stages by employing the one way ANOVA 'F' technique. Results: High statistical significance (P < 0.0001) was found in DNA damage levels between control and study groups. A stepwise increase in DNA damage levels with high statistical significance (P < 0.005) was also found between all the TNM stages. Conclusions: Statistically significant increased DNA damage levels in OSCC patients and their correlation to clinical staging suggest that comet assay may be used effectively to assess the prognosis of OSCC.

Daño basal del ADN en un grupo de individuos cubanos sanos mediante ensayo Cometa alcalino / Basal DNA damage on a group of Cuban healthy individuals by alkaline Comet assay / Dano basal no DNA em um grupo de indivíduos cubanos saudáveis através do ensaio Cometa alcalino

El ADN de las células humanas está sujeto de forma constante a diferentes tipos de daños debido a factores ambientales y a procesos metabólicos propios de la célula, que de no ser reparados y renovada su integridad, provocan inestabilidad genómica. Consecuentemente el daño en el ADN ha sido utilizado como marcador biológico en el biomonitoreo humano. El objetivo del presente trabajo fue determinar el daño basal del ADN en linfocitos aislados de sangre periférica de individuos voluntarios sanos, sin antecedentes patológicos y/o exposición a agentes genotóxicos. Se incluyó un total de 95 sujetos residentes en La Habana, con una edad promedio de 34±12 años, en los que el 71,13% correspondió a mujeres. Se empleó la variante alcalina del ensayo Cometa. Los niveles de daño fueron determinados en unidades arbitrarias. El daño basal del ADN, cuantificado en los 95 individuos, fue de 34,98±19,6 UA (25%=20,5 UA, 75%=47,5 UA). Los valores determinados constituyen los valores de referencia del laboratorio para el daño basal del ADN, en sujetos sanos. El punto de corte de daño al ADN, correspondiente al percentil 75, presenta aplicabilidad en el estudio de pacientes e individuos expuestos a xenobióticos. El uso de este valor permite la realización de estrategias de intervención oportunas que contribuyan a reparar tempranamente el daño detectado.

Human cell DNA is constantly subject to different types of damage due to environmental factors and metabolic processes of the same cell, which cause genomic instability if not repaired and completely renewed. Consequently, DNA damage has been used as a biomarker in human biomonitoring. The aim of this study was to determine basal DNA damage in lymphocytes isolated from peripheral blood of healthy volunteers with no medical history and/or exposure to genotoxic agents. A total of 95 subjects from the western region of Cuba, with an average age of 34±12 years, 71.13% of whom were female were included. Alkaline Comet assay variant was used. Damage levels were determined in arbitrary units. Basal DNA damage, measured in 95 subjects, was 34.98 ± 19.6 AU (25% = 20.5 AU, 75% = 47.5 AU). The values determined are the laboratory reference values for basal DNA damage in healthy subjects. The cutoff of DNA damage, corresponding to 75 percentile, has applicability in the study of patients and subjects exposed to xenobiotics. Use of this value allows for the realization of appropriate intervention strategies that help early repair of the damage detected.

O DNA das células humanas está constantemente sujeito a diferentes tipos de danos devido a fatores ambientais e a processos metabólicos próprios da célula, que se não forem reparados e a sua integridade renovada, provocam instabilidade genômica. Por conseguinte, o dano no DNA foi utilizado como um biomarcador no biomonitoramento humano. O objetivo deste estudo foi determinar o dano basal do DNA em linfócitos isolados de sangue periférico de voluntários saudáveis, sem antecedentes patológicos e/ou exposição a agentes genotóxicos. Um total de 95 indivíduos residentes em Havana foram incluídos, com uma idade em média de 34±12 dos quais 71,13% eram mulheres. Foi utilizada a variante alcalina do ensaio Cometa. Os níveis de dano foram determinados em unidades arbitrárias. O dano basal do DNA, medido nos 95 pacientes, foi de 34,98 ± 19,6 UA (25% = 20,5 UA, 75%=47,5 UA). Os valores determinados são os valores de referência do laboratório para o dano basal do DNA em indivíduos saudáveis. O ponto de corte de dano ao DNA, correspondente ao 75 percentil, tem aplicabilidade no estudo de pacientes e indivíduos expostos a xenobióticos. O uso deste valor permite a realização de estratégias de intervenção adequadas que ajudem a reparar precocemente o dano detectado.

Fenotipo de la reparación por escisión de nucleótidos en pacientes cubanos con hipersensibilidad al sol / Phenotype of the nucleotide excision repair in Cuban sun-hypersensitive patients

INTRODUCCIÓN: deficiencias en los mecanismos de reparación del ácido desoxirribonucleico constituyen un factor de riesgo para el desarrollo del cáncer, como ocurre en el xeroderma pigmentoso. OBJETIVOS: evaluar el fenotipo de la reparación por escisión de nucleótidos en pacientes cubanos con una elevada hipersensibilidad al sol, y la sospecha clínica de xeroderma pigmentoso en la fase eritematopigmentaria, mediante la variante alcalina del ensayo cometa. MÉTODOS: se estudiaron 28 pacientes, con predominio de las edades pediátricas. Como inductor del daño al ácido desoxirribonucleico se utilizó la radiación ultravioleta C (254 nm) a una dosis de 40 J/m². El daño del ácido desoxirribonucleico se cuantificó inmediatamente, después de irradiar las células (tiempo 0 minutos) y un tiempo después de la irradiación, incubado a 37 ºC en medio de cultivo, enriquecido con suero fetal al 10 % (tiempo 45 min). Con estos datos se determinó el por ciento de la diferencia en las unidades arbitrarias (UA) entre ambos momentos. RESULTADOS: no se obtuvieron diferencias significativas (p= 0,080976) entre el grupo de pacientes (224,23 UA) y el grupo de sujetos controles (195,43 UA). Los pacientes reconocieron y escindieron el daño inducido en el ácido desoxirribonucleico por luz ultravioleta C, con una eficiencia similar a la de los controles. CONCLUSIONES: el ensayo cometa alcalino acoplado a radiación ultravioleta C permitió identificar, claramente y de forma indirecta, el funcionamiento de los mecanismos de reparación por escisión de nucleótidos, donde actúan las proteínas XPA a XPG. Los sujetos en estudio fueron excluidos de presentar la forma clásica de la enfermedad.

INTRODUCTION: deficiencies in the deoxyribonucleic acid repair mechanisms are a risk factor for cancer as is the case of xeroderma pigmentosum. OBJECTIVES: to evaluate the phenotype of nucleotide excision repair in Cuban sun hypersensitive patients with clinical suspicion of xeroderma pigmentosum at erythematopigmentary phase, by using the Comet assay alkaline variant. METHODS: twenty eight patients mainly at pediatric ages were studied. The used DNA damage inducer was ultraviolet radiation C (254 nm) at 40 J/m2 dose. The DNA damage was quantified immediately after cell irradiation (0 minutes) and some time afterwards, then cultured at 37 ºC and enriched with 10 % fetal serum (45 minutes). This data allowed determining the percentage of difference in arbitrary units (AU) between both moments. RESULTS: there was no significant differences (p= 0.080976) between the group of patients (224.23 AU) and the control group (195.43 UA). The UV-C induced DNA damage was recognized and excised in the patients with similar effectiveness to that of the controls. CONCLUSIONS: the UV-C radiation-coupled alkaline comet assay allowed clearly and indirectly identifying the functioning of the nucleotide excision repair mechanisms in which XPA to XPG proteins influence. The studied subjects did not show the classical form of this disease.

Effects of high blood glucose fluctuation on DNA damage of diabetic rat retinal tissues / 国际眼科杂志(Guoji Yanke Zazhi)

AIM:To observe the situation of rat retinal tissue DNA damage at early diabetic period, discuss the role of the blood glucose fluctuations, and provide a new method for studying the pathogenesis of diabetic retinopathy ( DR) . METHODS: SD rats were randomly divided into four groups:normal control group (NC), normal fluctuation group ( NF ) , diabetes group ( DM ) and diabetes fluctuation group ( DF ) . Diabetic models were established through intraperitoneal injection of STZ. A certain amount of glucose was injected in the rats of group NF and DF in an intraperitoneal mode three times a day after the model was established, thereby causing blood glucose fluctuations. Rats were killed and the retinal tissues were taken in the 8th week. Single cell gel electrophoresis ( SCGE ) technique was adopted for detecting DNA injury extent in the retina tissue. RESULTS:Groups NF and DF showed significant and regular fluctuations. The curve of blood glucose fluctuations was relatively stable. All values of MBG, SDBG, LAGE and M were significantly increased compared with group NC. Group DF was increased more significantly. It was statistically significant (P CONCLUSION: Rat retinal tissues have DNA injury during early diabetic period. DNA injury is gradually aggravated with blood glucose fluctuation. It indicates that high blood glucose and blood glucose fluctuation are involved in the mechanism of cell DNA injury, and they may be one of DR early event, have played a certain role in the incidence of DR.

Evaluation of Oxidative DNA Damage Using an Alkaline Single Cell Gel Electrophoresis (SCGE) Comet Assay, and the Protective Effects of N-Acetylcysteine Amide on Zearalenone-induced Cytotoxicity in Chang Liver Cells

Zearalenone (ZEN) is a non-steroidal estrogenic mycotoxin produced by several species of Fusarium that are found in cereals and agricultural products. ZEN has been implicated in mycotoxicosis in farm animals and in humans. The toxic effects of ZEN are well known, but the ability of an alkaline Comet assay to assess ZEN-induced oxidative DNA damage in Chang liver cells has not been established. The first aim of this study was to evaluate the Comet assay for the determination of cytotoxicity and extent of DNA damage induced by ZEN toxin, and the second aim was to investigate the ability of N-acetylcysteine amide (NACA) to protect cells from ZEN-induced toxicity. In the Comet assay, DNA damage was assessed by quantifying the tail extent moment (TEM; arbitrary unit) and tail length (TL; arbitrary unit), which are used as indicators of DNA strand breaks in SCGE. The cytotoxic effects of ZEN in Chang liver cells were mediated by inhibition of cell proliferation and induction of oxidative DNA damage. Increasing the concentration of ZEN increased the extent of DNA damage. The extent of DNA migration, and percentage of cells with tails were significantly increased in a concentration-dependent manner following treatment with ZEN toxin (p < 0.05). Treatment with a low concentration of ZEN toxin (25 microM) induced a relatively low level of DNA damage, compared to treatment of cells with a high concentration of ZEN toxin (250 microM). Oxidative DNA damage appeared to be a key determinant of ZEN-induced toxicity in Chang liver cells. Significant reductions in cytolethality and oxidative DNA damage were observed when cells were pretreated with NACA prior to exposure to any concentration of ZEN. Our data suggest that ZEN induces DNA damage in Chang liver cells, and that the antioxidant activity of NACA may contribute to the reduction of ZEN-induced DNA damage and cytotoxicity via elimination of oxidative stress.

DNA damage in peripheral blood lymphocytes of patients with autosomal dominant polycystic kidney disease / 中华肾脏病杂志

Objective To detect DNA damage of peripheral blood lymphocytes in patients and family members of autosomal dominant polycystic kidney disease (ADPKD),and to study the effect of irradiation on genomic stability of lymphocytes. Methods Before and after 0.5 Gy radiation dose,single-cell gel electrophoresis (SCGE) was employed to analyze DNA damage of lymphocytes in 10 ADPKD patients (group A),3 members without clinical symptoms of a ADPKD family (group B) and 20 healthy control people (group C).The damage was estimated based on the content of DNA in tail (TDNA％) with comet analysis software (CASP). Results Both before and after irradiation,the TDNA％ (8.85％±0.14％,14.84％±0.77％) and the value-added (6.00％±0.77％) of TDNA％ of group A were significantly higher than those of group C (7.50％±0.37％,12.46％±0.26％,4.96％±0.44％) respectively.There were no significant differences between group B and group C or group A and group B.While 1 person in group B had higher TDNA％ as compared to group C both before and after irradiation. Conclusions The lymphocytes of ADPKD patients are more sensitive to ionizing radiation as compared to healthy people.The genomic instability in ADPKD patients or member of ADPKD family may trigger cystic formation in multi-organs when exposing to environmental agents. SCGE may provide a new approach to elucidate the pathogenesis and prognosis of ADPKD.

Evaluation of DNA damage in oral precancerous and squamous cell carcinoma patients by single cell gel electrophoresis.

Context: Single cell gel electrophoresis (SCGE) or "comet assay" is a rapid and very sensitive fluorescent microscopic method for detecting various forms of DNA damage at individual cell level. Aims: The aim of the present study was to detect the extent of DNA damage in oral cancer, oral submucous fibrosis (OSMF) and leukoplakia in comparison to normal individual. Settings and Design: A total of 44 consecutive patients with oral cancer (n=26), leukoplakia (n=12) and OSMF (n=6) and 10 healthy normal volunteers with normal oral epithelia (controls) were recruited from Dr. R. Ahmed Dental College and Hospital and were assessed for the extent of DNA damage using SCGE following clinical diagnosis. Materials and Methods: Peripheral blood was collected by venepuncture and comet assay was performed using SCGE. Mean tail length was compared between diagnostic groups and between different oral habit groups using t-tests and analysis of variance (ANOVA). Pearson's product moment correlation was used to examine the linear association between the extent of DNA damage and oral habit pack-years. Scheffe's pair-wise test was employed to adjust for multiple comparisons. Results: None of the controls were associated with any oral habits. Mean (±SD) tail lengths (in mm) for cancer (24.95 ± 5.09) and leukoplakia (12.96 ± 2.68) were significantly greater than in controls (8.54 ± 2.55, P<0.05). After adjustment, well-, moderately, and poorly differentiated carcinomas had significantly greater tail length than controls. Whereas the extent of DNA damage in cancer cases was significantly greater in leukoplakia than in compared to OSMF (11.03 ± 5.92), the DNA damage in latter was not different from controls. DNA damage for people with any oral habit (19.78 ± 7.77) was significantly greater than those with no habits (8.54 ± 2.55; P<0.0001). Conclusions: DNA damage measured by SCGE is greater in leukoplakia and squamous cell carcinoma, but not in OSMF. Deleterious oral habits are also associated with greater DNA damage.

DNA damage of gastric cancer cell line SGC7901 dyed by methylene blue after exposure to the cold light radiation of endoscope / 中华放射医学与防护杂志

Objective To study the co-effects of methylene blue(MB) and exposure with the cold light source on cell DNA damage, and to explore the mechanism involved. Methods The alkaline single cell gel electrophoresis was used to determine cell DNA damage. Apoptosis of the cells was determined by flow cytometry analysis using Annexin V-FITC/PI staining. DCFH-DA probe was used to determine endocellular Reactive Oxygen Species (ROS). Results The levels of DNA damage in the SGC7901 adenocarcinoma cells treated with methylene blue in the light were significantly increased compared to that of control ( F = 8.39, P＜0.05 ). The DNA damage levels were related to the length of time of light exposure, and the damage was recovered to a certain level after light withdrew. Cell apoptosis ( x2=7.71,P ＜0.05)and endocellular ROS level (F = 34.11, P＜0.01＝ increased significantly in the exposure group. Conclusions Methylene blue chromoendoscopy can induce DNA damage and cell apoptosis, and the mechanism may be associated with ROS produced by the photochemical reaction.

Assessment of DNA damage in radiation workers by using single cell gel electrophoresis / 中华放射医学与防护杂志

objective To assess the DNA damage of radiation workers in different grade hospitals,and to explore the correlation between the types of work or work time and the levels of DNA damage.Methods DNA single strand break were detected by using alkaline single cell gel electrophoresis(SCGE),and the comet was analyzed with CASP(Comet Assay Software Project).TDNA,TL,TM and OTM were calculated.Results The parameters of SCGE in the radiation greup were higher than those of control group(F=3.93,P<0.01).The significant difference was found not only among the different types of work or difierent work time,but also among the different grade hospitals(F=1.83,1.9 1,P<0.05).Conclusions Various levels of DNA damage could be detected in the radiation workers of the two hospitals.DNA damage of radiation workers is less serious in the higher-grade hospital than the lower grade one.Different types of work or work time might affect the DNA damage level.

Investigation on DNA damage of mouse mononuclear cells in peripheral blood induced by low-dose T-2 toxin and deoxynivalenol alone or in combination / 中国地方病学杂志

Objective To investigate the characteristics and extent of mononuclear ceils DNA damage in peripheral blood of mice fed with low dose T-2 toxin and Deoxynivalenol(DON) alone or in combination and to explore the long-term toxicity of the toxin at sub-clinical dose. Methods Eighty female Balb/c mice weighing (14.0 ± 1.5)g 3 weeks after birth were divided randomly into control group, T-2 toxin group, DON group and T-2 toxin combined with DON group according to their body weight, 20 in each group. The mice were injected intraperitoneally T-2 toxin(5 μg·kg-1·d-1), DON(20 μg·kg-1·d-1), T-2 toxin(5 μg·kg-1·d-1) combined with:DON (20μg·kg-1·d-1)respectively,control group were treated by isotonic NaCl. In 16 weeks and 21 weeks of exposure, the tail blood of the mice was collected. The comet rate, tail DNA content,tail length and tail extent moment of mouse mononuclear ceils in peripheral blood was observed using single cell gel electrophoresis(SCGE). Results ① In T-2 toxin group,tail DNA content,tail length and tail extent moment were (27.71 ± 15.85)%, (13.67 ± 5.56)μm, 4.26 ± 3.83 at 16 weeks and (28.38 ± 15.57)%, (13.83 ± 5.47)μm, 4.37 ± 3.82 at 21 weeks, all levels of the indexes increased. In the control group, the corresponding values were (11.87 ± 4.61)%, (10.59±6.70)μm, 1.34±0.98 at 16 weeks and (11.31 ± 3.94)%, (10.83 ± 7.05)μm, 1.29±1.01 at 21 weeks, the differences in the two groups were significant (all P < 0.05) ;②In DON group, the comet rate of cells, tail DNA content and tail extent moment of comet ceils were 5.62%, (28.13 ±13.31)%, 3.39 ± 2.35 at 16 weeks and 7.71%, (29.17 ± 15.12)%, 5.70 ± 4.17 at 21 weeks. In the control group, the tailing rate was 4.34% at 16 weeks and 4.38% at 21 weeks, the differences in the two groups were significant (all P < 0.05);③In the group of T-2 toxin combined with DON,the comet rate, tail DNA content, tail length and tail extent moment was 6.21%, (30.14 ± 15.48)%, (16.93± 6.58)μm, 5.54 ± 4.22 at 16 weeks and 8.17%, (30.85 ± 15.76)%, (17,21±6.45)μm, 5.70 ± 4.17 at 21 weeks. Moreover, the levels were significantly higher than that in the control group(all P < 0.05). The tail DNA content and length of comet cell tail significantly increased in the combine group compared with T-2 group or DON group(P < 0.05). Conclusions Low dose T-2 toxin or DON can definitely result in DNA damage of mononuclear cells in peripheral blood of mice. The damage induced by T-2 toxin combined with DON is severer than that caused by T-2 toxin or DON alone.

Adaptive responses on chromosome aberration and DNA breakage of peripheral lymphocytes from workers exposed to thorium and rare earth mixed dust in Baotou Steel Plant / 中华放射医学与防护杂志

Objective To explore if the occupational exposure to low dose thorium could induce adaptive response in peripheral lymphocytes.Methods 40 individuals.who exposed to thorium and rare earth mixed dust(exposure group) or control in Baotou Steel Plant, were selected, and chromosome aberrations were analyzed.Then the peripheral blood samples were irradiated in vitro with 2 Gy60Co γ-rays,and unstable chromosome aberration or DNA stand breakage analysis using single cell gel electrophoresis was performed. Results The dicentrics before 2 Gy exposure in exposure group was higher than that in control(P>0.05). But the dicentries after 2 Gy exposure in exposure group was lower than that in control,but not significantly (P>0.05).The tricentrics in exposure group was significantly lower than that in control(U=3.1622, 0.0ol<P<0.002).The DNA strand breakage in control group was significantly higher than that in exposure group(t=25,P<0.001).Conclusions Occupational exposure to low dose thorium could induce the adaptive response on chromosome aberration and DNA strand breakage in peripheral lymphocytes.

DNA Damage in Testicular Cells Induced by Acrylamide through Different Exposure Routes in Mice / 环境与健康杂志

Objective To know DNA damage effect in testicular cells in mice induced by acrylamide through three exposure routes,intraperitoneal injection,oral exposure and skin exposure.Methods Twenty-four healthy male KM mice were randomly divided into 4 groups,including the blank control group,intraperitoneal injection group,oral exposure group and skin exposure group,6 in each.The exposure dose was 25 mg(/kg?d),for 5 consecutive days,once a day.On the sixth day after the first exposure,the changes of body weight and testis coefficient were observed.The tail length,tail DNA%,tail moment,olive tail moment of testicular cells were detected by single cell gel electrophoresis.Results The body weights of intraperitoneal injection group and oral exposure group decreased significantly (P

Clastogenicity of Piper cubeba (Piperaceae) seed extract in an in vivo mammalian cell system

The plant Piper cubeba is widely distributed in tropical and subtropical regions and is used medically for various purposes but has not yet been evaluated for genotoxicity. We used male and female Swiss mice and Wistar rats and the comet assay and micronucleus test to investigate the mutagenic potential of a crude extract of P. cubeba seeds. The rodents were administered 0.5 g kg-1, 1.0 g kg-1 and 1.5 g kg-1 of the extract by gavage. For the Swiss mice, peripheral blood was collected 24 h after treatment for the comet assay, and at 48 and 72 h for the micronucleus test. For the Wistar rats, peripheral blood and hepatic cells were collected for the comet assay and bone marrow cells were collected for the micronucleus test 24 h after treatment. At 1.5 g kg-1, the highest dose tested, the extract induced a statistically significant increase in both the mean number of micronucleated polychromatic erythrocytes and the level of DNA damage in the rodent cell types analyzed. Under our experimental conditions, the P. cubeba seed extract was genotoxic in vivo when administered orally to mice and rats.

Genotoxicity of Liquid Formaldehyde on Brain Cells of Goldfishs / 医学研究杂志

Objective To explore theDNA damage of brain cells of goldfishs through formaldehyde exposure.Methods The goldfishs were treated with liquid formaldehyde at different concentrations(0.01 mmol/L,0.1 mmol/L和1mmol/L)for three days.Single cell gelelectrophoresis technique(comet assay)was used to test the DNA damage of the brain cells.Results Formaldehyde caused significant DNA strand break at the concentration of 0.01mmol/L,0.1mmol/L and 1.0mmol/L.Conclusions Formaldehyde was both a DNA strand breaker when the concentration is higher,it may cause crosslinkagent to the brain in vivo.