Study of Low-intensity 2450-MHz Microwave Exposure Enhancing the Genotoxic Effects of Mitomycin C Using Micronucleus Test and Comet Assay in vitro

Objective To determine the interaction between 2450-MHz microwaves (MW) radiation and mitomycin C (MMC). Methods The synergistic genotoxic effects of low-intensity 2450-MHz microwave and MMC on human lymphocytes were studied using single cell gel electrophoresis (SCGE) assay (comet assay) and cytokinesis-blocked micronucleus (CBMN) test in vitro. The whole blood cells from a male donor and a female donor were either only exposed to 2450-MHz microwaves (5.0 mW/cm2) for 2 h or only exposed to MMC (0.0125 μ/mL, 0.025 μg/mL, 0.05μg/mL and 0.1 μg/mL) for 24 h; and the samples were exposed to MMC for 24 h after exposure to MW for 2 h. Results In the comet assay, the comet lengths ( 29.1 μm and 25.9 μm) of MW were not significantly longer than those (26.3 μrn and 24.1 μm) of controls (P>0.05). The comet lengths (57.4 μm, 68.9 μm, 91.4 μm, 150.6μm and 50.6 μm, 71.7μm, 100.1 μm, 145.1 μm) of 4 MMC groups were significantly longer than those of controls (P<0.01). The comet lengths (59.1 μm, 92.3 μm, 124.5 μm, 182.7 μm and 57.4 μm, 85.5 μm, 137.5 μm, 178.3 μm) of 4 MW plus MMC groups were significantly longer than those of controls too (P<0.01). The comet lengths of MW plus MMC groups were significantly longer than those of the corresponding MMC doses (P<0.05 or P<0.01) when the doses of MMC were ≥50.025 μg/mL. In the CBMN, the micronucleated cell (MNC) rates of MW were 5% and 6%, which showed no difference compared with those (4‰ and 4‰) of controls (P>0.05). The MNC rates of 4 MMC groups were 8‰, 9‰, 14‰, 23‰ and 8‰, 8‰, 16‰, 30‰ respectively. When the doses of MMC were 3≥0.05 μg/mL, MNC rates of MMC were higher than those of controls (P<0.05). MNC rates of 4 MW plus MMC groups were 12‰, 13‰, 20‰, 32‰ and 8‰, 9‰, 23‰, 40‰. When the doses of MMC were 5≥0.05 μg/mL, MNC rates of MW plus MMC groups were much higher than those of controls (P<0.01). MNC rates of 4 MW plus MMC groups were not significantly higher than those of the corresponding MMC doses. Conclusion The low-intensity 2450-MHz microwave radiation can not induce DNA and chromosome damage, but can increase DNA damage effect induced by MMC in comet assay.

Assessment of Human DNA Repair (NER) Capacity With DNA Repair Rate (DRR) by Comet Assay

Objective Alkaline comet assay was used to evaluate DNA repair (nucleotide excision repair, NER) capacity of human fresh lymphocytes from 12 young healthy non-smokers (6 males and 6 females). Methods Lymphocytes were exposed to UV-C (254 nm) at the dose rate of 1.5 J/m2/sec. Novobiocin (NOV) and aphidicolin (APC), DNA repair inhibitors, were utilized to imitate the deficiency of DNA repair capacity at the incision and ligation steps of NER. Lymphocytes from each donor were divided into three grougs: UVC group, UVC plus NOV group, and UVC plus APC group. DNA single strand breaks were detected in UVC irradiated cells incubated for 0, 30, 60, 90, 120, 180, and 240 min after UVC irradiation. DNA repair rate (DRR) served as an indicator of DNA repair capacity. Results The results indicated that the maximum DNA damage (i.e. maximum tail length) in the UVC group mainly appeared at 90 min. The ranges of DRRs in the UVC group were 62.84%-98.71%. Average DRR value was 81.84%. The DRR difference between males and females was not significant (P<0.05). However, the average DRR value in the UVC plus NOV group and the UVC plus APC group was 52.98% and 39.57% respectively, which were significantly lower than that in the UVC group (P<0.01). Conclusion The comet assay is a rapid, simple and sensitive screening test to assess individual DNA repair (NER) capacity. It is suggested that the time to detect DNA single strand breaks in comet assay should include 0 (before UV irradiation), 90 and 240 min after exposure to 1.5 J·m-2 UVC at least. The DRR, as an indicator, can represent the individual DNA repair capacity in comet assay.

Genotoxicity evaluation of drinking water sources in human peripheral blood lymphocytes using the comet assay

The potential harm of organic pollutants in drinking water to human health is widely focused on in the wodd; more and more pollutants with genotoxic substances are released into the aquatic environment. Water source samples were collected from 7 different localities of Nanjing City. The potential genotoxicity of organic extracts from drinking water sources were investigated by means of the comet assay in human peripheral lymphocytes. The results showed that all the organic extracts from all the water source samples could induce DNA damages of human peripheral blood lymphocytes at different levels. A significant difference （P 〈 0.01） was observed when compared with the solvent control, The DNA damage increased with the increase of the dosage of the original water source. Significant differences of DNA damage were observed in different drinking water sources, as shown by the multiple comparisons analysis at the dosage of 100x; the degree of DNA damage treated by Hushu waterworks （at town level） was the most serious, the arbitrary units （AU） was 141.62±6.96, however, that of Shangyuanmen waterworks （at city level） was only 109.64±2.97. The analysis also revealed that the genotoxicity of town＇s water sources was higher than that of the city. The results demonstrated that the comet assay can be successfully applied to the genotoxicity monitoring programs of drinking water sources.

Shortening of alkaline DNA unwinding time does not interfere with detecting DNA damage to mouse and human spermatozoa in the comet assay

The comet assay was performed on mouse and human spermatozoa to examine the effect of alkaline DNA unwinding time. The spermatozoa were treated in vitrowith the DNA-damaging agents, methyl methanesulfonate （MMS） or hydrogen peroxide （Hz02）, and then embedded in agarose gel on glass sl ides. The slides were immersed in alkaline solution （〉pH 13） for 1, 5, 10 and 20 min, and then subjected to the electrophoresis under neutral conditions. In mouse spermatozoa, comet tails seen in solvent controls became brighter and longer as the alkaline DNA unwinding time increased. However, in the MMS-treated mouse spermatozoa, a smaller difference in the damage from that in the solvent control was seen with time within a dose. DNA damage induced by H2O2 could also be detected accurately after alkali treatment for 1-20 min. In human spermatozoa, DNA damage induced by MMS and H2O2 could be detected in a dose-dependent manner after alkali treatment for 1 min. The ability of the comet assay to detect DNA damage was not adversely affected by the short period （1 min） of the alkaline DNA unwinding time.

Genotoxicity of Three Avermectins on Polypedates megacephalus Tadpoles Using the Comet Assay

Avermectins are a new class of macrocyclic lactones derived from mycelia of the soil actinomycete, and are used as effective agricultural pesticides and antiparasitic agents. However, run-off from crops treated with avermectins may contaminate various bodies of water, and accumulated to certain concentrations to impact the development of aquatic animals. Here, we tested the genotoxicity of three avermectins （abamectin, ABM; ivermectin, IVM; and emamectin benzoate, EMB） on Polypedates megacephalus tadpoles by the alkaline single-cell gel electrophoresis assay. Tadpoles were treated for 48 h in the laboratory with different concentrations of these three agents, 0.006, 0.012, 0.018, 0.024, 0.030 mg/L for ABM, 0.003, 0.006, 0.009, 0.012, 0.015 mg/L for IVM and 0.04, 0.06, 0.08, 0.10, 0.12 mg/L for EMB, and then measured their DNA damage by the Comet assay tail factor %. The concentrations of resulted in highly significant increases in DNA damage of the tadpoles were found above the concentration threshold of 0.012 mg/ L ABM, 0.003 mg/L IVM and 0.06 mg/L EMB and linear correlations between the intensity of DNA damage and the concentrations of these three avermectins. Our results showed clearly that avermectins caused dose dependent DNA damage on amphibian tadpoles, and there might be a control on the misuse of avermectins.

DNA Damage （Comet Assay） as Biomarker of Cd Exposure in Marine Seed Scallops Mizuhopecten Yessoensis Age 1 Year

Cadmium-induced DNA degradation in gill cells of the scallop Mizuhopectenyessoensis was assessed using the comet assay （single-cell gel electrophoresis）. Accumulation of highly toxic cadmium in the gill cells of bivalve is accompanied by the damage of the cell genome revealed as DNA migration in the comet assay. The main mechanisms of Cd effects on the integrity of the DNA structure are discussed.

The genotoxic effects of benzo[a]pyrene and methamidophos on black porgy evaluated by comet assay

In this study, two common pollutants (benzo[a]pyrene and methamidophos) in marine environment were tested by comet assay for their inducement of in vivo genotoxic effect to the blood cells of black porgy ( Acanthopagrus schlegeli). The fish was exposed to 2 μg/L of benzo[a]pyrene (BaP) and methamidophos, and their mixture. The assay was performed on whole blood at 2 h, 5 h, 24 h and 96 h exposure intervals. A signifi- cant increase in DNA damage was observed in each treatment with the pollutants. Additive effect of BaP and methamidophos was also found in the experiment. However, the decrease ratios of DNA damage for 5 h and 96 h exposure interals compared with 2 h and 24 h exposure ones, respectively, were noticed. This phenomenon may be explained by the function of repairing process via enzyme cytochrome P450 in the animal. Evidence of the genotoxicity of organophosphorus pesticides (OPs) and polynuclear aromatic hydrocarbons (PAHs) on marine fish are discussed in this paper.

DNA damage levels in systemic lupus erythematosus patients with low disease activity:An evaluation by comet assay

Oxidative stress has been implicated in the inflammatory process of Systemic Lupus Erythematosus (SLE), particularly by the formation of anti-DNA autoantibodies, which can lead to DNA damage. The aim of this study was to investigate, through comet assay, whether the level of DNA damage in SLE patients is different from that of healthy subjects. Twenty-five adult SLE patients with SLEDAI up to ten, and 25 healthy subjects were paired according to age, gender and Body Mass Index (BMI). Other anthropometric variables were also assessed. Comet assay was assessed as the marker of oxidative stress described as DNA Damage (DD) percentage. Waist Circumference (WC), Hip Circumference (HC) and BMI were also performed. Exclusion criteria for patients and controls comprised smoking and other chronic disorders. Level of damage index was remarkably higher in SLE patients than in controls, and no significant differences between the groups were found for age, BMI, WC and HC. No stratification concerning gender was performed, since there were just two males per group. No correlation was observed between BMI and DD (%). DD increased in SLE, which reflects the oxidant/antioxidant imbalance in these patients. These findings support an association between oxidative stress and SLE. This stronger correlation observed in patients with low disease activity may be useful in elucidating the mechanisms of disease pathogenesis.

Comet assay and cytokinesis-blocked micronucleus test for monitoring the genotoxic effects of X-ray radiation in humans

Obejctive To assess the genotoxic effects of X ray radiation on human populations Methods The single cell gel electrophoresis (SCGE) and cytokinesis blocked micronucleus (CBMN) test were applied as biological dosimeters to detect DNA damage and abnormalities in human peripheral lymphocytes of subpopulation exposed to X ray radiation The subjects were divided into four groups: 12 radiation patients; 13 intervention radiation therapy doctors; 32 radiation diagnostians; 28 controls Results The average comet lengths of the four groups were 128 17±4 49?μm, 88 09±5 39?μm, 72 68±2 57?μm and 32 87±0 57?μm, respectively The difference in average comet length between any two groups was highly significant ( P <0 01) The average micronucleated cell (MNC) rates (‰) of the four groups were 12 33±0 85, 9 75±1 02, 8 48±0 66 and 3 18±0 36, respectively The difference of MNC rates of Group 1 vs 3, 1 vs 4, 2 vs 4 and 3 vs 4 was highly significant ( P <0 01), and the difference of Group 1 vs 2 was significant ( P <0 05), but there was no difference of MNC rate in Group 2 vs 3 ( P >0 05) Conclusions This study showed that both the comet assay and the CBMN test could be used to monitor populations exposed to X ray radiation, but the comet assay seems to be more sensitive than the CBMN test

Forensic application of comet assay:an emerging technique

Postmortem interval(PMI)estimation is a recurring problem in the field of forensic medicine.Conventional methods are effective but are insufficient to estimate accurate and precise time of death or PMI.In addition,degradation of biological samples is another major problem in forensic science which affects the investigation process and misleads the result.Some previous studies reported that DNA fragmentation has strong correlation with PMI.DNA fragmentation increased with prolonged PMI.Comet assay is a rapid sensitive,versatile,reliable and cost effective technique that is specifically used for qualitative and quantitative estimation of nuclear DNA fragmentation.Due to this attribute,comet assay can help to estimate accurate and precise time of death for some extent that is for early PMI estimation.In addition,two confounding factors are responsible for DNA fragmentation:(1)micro-organism;(2)environmental condition.Here,comet assay plays a dual role:(1)partially degraded samples get repaired using repair enzyme;(2)accurate time since deposition can be measured without using repair enzyme.Furthermore,this assay can also help to identify potential exposures of environmental-released chemicals/toxicants and its deleterious effects on human population.In this way,comet assay shows its versatile applications that could be useful for forensic investigation.Therefore,with the help of this review,an attempt was made to explore the versatility of comet assay technique for forensic applications and its future perspective.

Single Cell Gel Electrophoresis Assay of Porcine Leydig Cell DNA Damage Induced by Zearalenone

[Objective] This study aimed to investigate the effect of zearalenone (ZEN) on DNA damage of porcine leydig cells. [Method] Porcine leydig cells cultured in vitro were collected to determine the median lethal dose (LD50) of ZEN with tetrazolium-based colorimetric assay (MTT assay). Comet assay was carried out to detect the DNA damage of porcine leydig cells exposed to at 0 (negative group), 1, 5, 10, 20, 40 μmol/L of ZEN. [Result] The percentage of cell tail was 16.67%, 34.00%, 40.67%, 52.00% and 64.67% under 0, 1, 5, 10 and 20 μmol/L of ZEN, respectively; the differences between the percentages of cell tail in various experimental groups had extremely significant statistical significance compared with the negative group (P<0.01), showing a significant dose-effect relationship; Tail length in various groups was 57.60±4.78, 57.75±6.25, 78.97±5.83, 100.50±6.94 and 146.83±12.31 μm, respectively; Tail DNA % in various groups was 21.29±2.25%, 22.24±2.43%, 31.21±6.27%, 37.45±4.33% and 60.68±9.83%, respectively; Tail length and Tail DNA % in experimental groups with ZEN concentration above 5 μmol/L showed significant differences (P<0.05) compared with the negative group, which showed an upward trend with the increase of ZEN concentration. [Conclusion] ZEN has genotoxic effect on porcine leydig cells, which can cause DNA damage, with a significant dose-effect relationship.

Response of Lymphocytes to Radiation in Untreated Breast Cancer Patients as Detected with Three Different Genetic Assays

Objective To detect the response of lymphocytes to radiation in untreated breast cancer patients with three different genetic assays. Methods Blood samples were collected from 25 untreated patients and 25 controls. Each blood sample was divided into two parts： one was irradiated by 3-Gy X-ray （irradiated sample）, the other was not irradiated （non-irradiated sample）. The radiosensitivity of lymphocytes was assessed by comet assay, cytokinesis-block micronucleus （CBMN） assay and 6-TG-resistant cells scored （TG） assay. Results The baseline values of micronucleated cell frequency （MCF） and micronucleus frequency （MNF） in the patients were significantly higher than those in the controls （P〈0.01）, and 3-Gy X-ray induced genetic damage to lymphocytes in the patients increased significantly as compared with that in the controls as detected with the three genetic assays （P〈0.01）. The proportion of radiosensitive cases in the patient group was 48% for the mean tail length （MTL）, 40% for the mean tall moment （MTM）, 40% for MCF, 44% for MNF, and 48% for mutation frequencies of the hprt gene （Mfs-hprt）, respectively, whereas the proportion of radiosensitive cases in the control group was only 8% for all the parameters. Conclusion The difference in the lymphocyte radiosensitivity between the breast cancer patients and the controls is significant. Moreover, there are wide individual variations in lymphocyte radiosensitivity of patients with breast cancer. In some cases, the radiosensitivity of the same patient may be different as detected with the different assays. It is suggested that multiple assays should be used to assess the radiosensitivity of patients with breast cancer before therapy.

Oxidative Damage to DNA and Its Relationship With Diabetic Complications

Objective To detect the oxidative DNA damage in diabetic patients and to investigate the relationship of oxidative DNA damage with diabetes and diabetic nephropathy. Methods Single cell gel electrophoresis （SCGE） was used to detect the DNA strand breaks in peripheral blood lymphocytes, and oxidative DNA damage product and serum 8-OHdG were determined by a competitive ELISA in 47 cases, including 25 patients without diabetic complications, 22 patients with diabetic nephropathy and 25 normal control subjects. Results Diabetic patients showed greater oxidative damage to DNA. The percentage of comet cells and the length of DNA migration （comet tail length） of peripheral blood lymphocytes were significantly increased in patients with diabetes, and significantly higher in patients with diabetic nephropathy than in diabetic patients without vascular complications （P〈0.05）. There was a significant increase in serum 8-OHdG in diabetic patients compared with normal subjects （P〈0.05）. Moreover, serum 8-OHdG was much higher in patients with diabetic nephropathy than in diabetic patients without vascular complications （P〈0.05）. Coneluslon There is severe oxidative DNA damage in diabetic patients. Enhanced oxidative stress may be associated with diabetes, especially in patients with diabetic nephropathy.

Genotoxicity evaluation and a primary risk assessment of organic pollutants in the drinking water sources of Nanjing, China

An increasing number of industrial, agricultural, and commercial chemicals in the aquatic environment leads to various deleterious effects on organisms, which is becoming an increasingly serious problem in China. In this study, the comet assay was conducted to investigate the genotoxicity to human body caused by organic concentrates in the drinking water sources of Nanjing City from Yangtze River of China, and health and ecology risk due to expose to these organic pollutants were evaluated with the multimedia environmental assessment system （MEAS）. For all the water samples, they were collected from four different locations in the drinking water sourcr samples, es of Nanjing City. The results of the comet assay showed that all the organic concentrates from the water samples could induce different levels DNA damages on human peripheral blood lymphocytes, and a statistically significant difference （p〈0.01） was observed compared with the solvent control, which demonstrated the genotoxicity was in existence. According to the ambient severity （AS） of individual compound, we had sorted out the main organic pollutants in the drinking water source of the four waterworks, and the results showed that there was some potential hazard to human body for all the source water, namely the total ambient severity （TAS） of health for each water source was more than 1. However, the TAS of ecology for each water source was less than 1, which indicated that it was safe to ecology. The results of this investigation demonstrate the application of the comet assay and the MEAS in aquatic environmental monitoring studies, and the comet assay found to be fast, sensitive, and suitable for genotoxicity monitoring programs of drinking water source.

Effect of Low Level Subchronic Microwave Radiation on Rat Brain

Objective The present study was designed to investigate the effects of subchronic low level microwave radiation （MWR） on cognitive function, heat shock protein 70 （HSP70） level and DNA damage in brain of Fischer rats. Methods Experiments were performed on male Fischer rats exposed to microwave radiation for 90 days at three different frequencies： 900, 2800, and 2450 MHz. Animals were divided into 4 groups： Group I： Sham exposed, Group I1： animals exposed to microwave radiation at 900 MHz and specific absorption rate （SAR） 5.953 x 10-4 W/kg, Group II1： animals exposed to 1800 MHz at SAR 5.835 x 20-4 W/kg and Group IV： animals exposed to 2450 MHz at SAR 6.672 x 10-4 W/kg. All the animals were tested for cognitive function using elevated plus maze and Morris water maze at the end of the exposure period and subsequently sacrificed to collect brain tissues. HSP70 levels were estimated by ELISA and DNA damage was assessed using alkaline comet assay. Results Microwave exposure at 900-2450 MHz with SAR values as mentioned above lead to decline in cognitive function, increase in HSP70 level and DNA damage in brain. Conclusion The results of the present study suggest that low level microwave exposure at frequencies 900, 2800, and 2450 MHz may lead to hazardous effects on brain.

Genotoxic and Nongenotoxic Effects of Glycidyl Methacrylate on Human Lung Fibroblast Cells

Objective To evaluate the genotoxic and nongenotoxic effects of short-term exposure to glycidyl mathacrylate (GMA) on human lung fibroblast cells (2BS cells) in vitro. Methods DNA strand breakage was determined by single cell gel electrophoresis, and DNA ladder formation assay and flow cytometric analysis were carried out to detect apoptic responses of cells to GMA exposure. The HPRT gene mutation assay was used to evaluate the mutagenicity, and the effect of GMA on gap junctional intercellular communication (GJIC) in the exposed cells was examined with the scrape loading/dye transfer technique. The ability of GMA to transform 2BS cells was also tested by an in vitro cell transformation assay. Results Exposure to GMA resulted in a dose-dependent increase in DNA strand breaks but not apoptic responses. GMA was also shown to significantly induce HPRT gene mutations and morphological transformation in 2BS cells in vitro. In contrast, GMA produced a concentration-dependent inhibition of GJIC. Conclusions GMA elicits both genotoxic and nongenotoxic effects on 2BS cells in vitro. The induction of DNA damage and gene mutations and inhibition of GJIC by GMA may casually contribute to GMA-induced cell transformation.

Effects of Heavy Metal Ions (Cu^(2+), Pb^(2+) and Cd^(2+)) on DNA Damage of the Gills, Hemocytes and Hepatopancreas of Marine Crab, Charybdis japonica

There are rising concerns about the hazardous effects of heavy metals on the environment. In this study, comet assay and DNA alkaline unwinding assay were conducted on the tissues (gills, hepatopancreas, and hemocytes) of Charybdis japonica in order to illustrate genotoxicity of three heavy metal ions (Cu2+, Pb2+, and Cd2+) on the marine crabs C. japonica. The crabs were exposed to Cu2+ (10, 50, and 100 ?g.L?1), Pb2+ (50, 250, and 500 ?g L?1) and Cd2+ (5, 25, and 50 ?g L?1), and the tissues were sampled at days 0.5, 1, 3, 6, 9, and 15. DNA alkaline unwinding assay was used for testing the DNA single strand break in gills and hepatopancreas and comet assay was employed for testing the DNA damage in hemocytes. The results showed that the DNA damage (F-value) of gills in the crabs exposed to the three heavy metals was decreased gradually during the exposure periods and there was a dose-time response relationship in certain time, suggesting that the levels of DNA single strand break in all the experimental groups increased significantly compared to the controls. Changes of F-value in hepatopancreas of the crabs exposed to the three heavy metals were similar to those in gills except that the peak values were found in the 500 ?g L?1 Pb2+ treatment group at day 3 and the 50 ?g L?1 Cd2+ treatment group at day 9. The ranks of DNA damage in gills and hepatopancreas induced by the three heavy metal ions (50 ?g L?1, day 15) were Cd2+ >Pb2+ >Cu2+ and Pb2+ >Cu2+ >Cd2+. The levels of DNA damage in gills were higher than those in hepatopancreas in the same experimental group. It can be concluded that indices of DNA damage can be used as the potential biomarkers of heavy metal pollution in marine environment.

Repeated vitrification/warming of human sperm gives better results than repeated slow programmable freezing

In this study, we compared the effects of repeated freezing/thawing of human sperm by our in-house method of rapid freezing with slow programmable freezing. Sperm samples from 11 normozoospermic subjects were processed through density gradients and divided into three aliquots： non-frozen, rapid freezing and slow programmable freezing. Sperm in the rapid freezing group had better motility and viability than those in the slow freezing group （P〈O.01） after the first, second and third cycles of freezing/thawing, but there was no difference in morphology. In the second experiment, rapid freezing was repeated three times in 20 subjects. The samples from each thawing cycle were evaluated for DNA fragmentation using the alkaline comet assay. DNA fragmentation began to increase considerably after the second cycle of freezing/thawing, but to a level that was not clinically important. In the third experiment, rapid freezing was done repeatedly in 10 subjects, until no motile sperm were observed after thawing. The median number of repeated freezing/thawing that yielded no motile sperm was seven （range： 5-8, mean： 6.8）. In conclusion, we demonstrated that repeated freezing/thawing of processed semen using our rapid freezing method gave better results than standard slow programmable freezing. This method can help maximize the usage of precious cryopreserved sperm samples in assisted reproduction technology.

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_2O_2) 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 H_2O_2 induced DNA damages. In this review, relevant researches on the effect of medicinal plants on DNA damages induced by H_2O_2 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. Sufficient in 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.

Oxidative Stress, Biochemical and Histopathological Alterations in the Liver and Kidney of Female Rats Exposed to Low Doses of Deltamethrin (DM):A Molecular Assessment

Objective To evaluate histopathological alterations of the liver and kidney of female rats exposed to low doses of DM and its potential genotoxic activity. Methods Female Wistar rats were randomly assigned to control （3 groups, 6 rats in each） and treatment groups （3 groups, 6 rats in each）. They were subjected to subcutaneous injections of DM （at doses of 0.003, 0.03, and 0.3 mg/kg bw/d） after 30, 45, and 60 d, respectively. Results Significant alterations were recorded in liver parenchyma induced by hepatic vacuolization, fragmented chromatin in nuclei, dilatation of sinusoids and congestions. Lesions within proximal and distal tubules were observed in the kidneys. Tissue congestions and severe alterations within glomeruli were visible. DM as a pyrethroid insecticide induced significant increase （P〈_O.05） of plasma MDA concentrations after 45 d. A significant increase （P_〈0.05） in plasma ALT （after 45 and 60 d） and AST （after 60 d） concentrations was recorded as compared to controls. During the whole experimental period the toxic agent provoked significant DNA damages （P〈0.05）, especially in the dominance of classes 3 and 4 of obtained comet. Conclusion DM even at a very low dose displays harmful effects by disrupting hepatic and renal function and causing DNA damages in puberscent female rats. Low doses of DM are hepatotoxic and nephrotoxic.