Comet Assay

Background: This study investigated the possible protective effects of bilberry extract after exposing rat eyes to ultraviolet-B (UV-B) radiation. Methods: Four groups of rats were included in this study, each consisting of 10 Wistar rats. The first group acted as the control, and the second group was exposed to UV-B, 5 KJ/m2 (λm = 300 nm), for 15 minutes. The third group was orally administered bilberry extract (160 mg twice per day) for two weeks before exposure to the UV-B, while the fourth group was administered the same dose of bilberry extract for two weeks before euthanisation. A comet assay was used to examine DNA damage, while the malondialdehyde (MDA) level and superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT), activities were measured in the lens. Results: After exposing the rats to UV-B radiation, the mean percentage tail DNA and tail moment were significantly increased (P < 0.001) when compared to the control group. In the same context, the lens tissue MDA levels and CAT activity were also significantly increased (P < 0.001). The supplementation of the bilberry extract was found to improve the comet assay parameters and enzymatic activity of the rat lens tissue. Conclusion: The administration of bilberry led to a decrease in the oxidative stress in the lens tissues and DNA damage induced by UV-B radiation in the lenses of Wistar rats.
Vaccinium myrtillus ; DNA ; Comet Assay ; Malondialdehyde

OBJECTIVETo explore the feasibility of single-cell gel electrophoresis (SCGE) as one of lab tests to examine DNA breakage for the diagnosis of Fanconi anemia (FA). Case Record A 4-year-and-10-month old boy presented with cryptorchism, deformities of both thumbs and esotropia of right eye. He developed thrombocytopenia and anemia when he was 3 year- and -2-month old. He was clinically diagnosed as FA.

METHODS AND RESULTSDNA breakage of peripheral white blood cells from the patient and his parents was examined with SCGE. The percentages of cells with chromosome breakage (comet-tail positive cells) were 100%, 90% and 52% for the patient,his father and mother, respectively, while that were only 2% and 5% in two normal same-age children (P <0. 001). The micronucleus-positive lymphocytes was 6.74% in the patient, being also much higher than normal value (0.40%).

CONCLUSIONSCGE disclosed DNA breakage in the patient with FA, suggesting that it could be used as a test for determining DNA breakage of FA.

Child, Preschool ; Comet Assay ; Fanconi Anemia ; diagnosis ; Humans ; Male

Comet Assay ; DNA Damage ; Humans ; Occupational Exposure ; Population Surveillance ; methods

Comet Assay ; DNA Damage ; DNA Repair ; In Situ Hybridization, Fluorescence ; methods

High consumption of fruits and vegetables has been suggested to provide some protection to smokers who are exposed to an increased risk of numerous cancers and other degenerative diseases. Carrot is the most important source of dietary beta-carotene. Therefore, the objective of this study was to investigate whether carrot juice supplementation to smokers can protect against lymphocyte DNA damage and to compare the effect of supplementation of capsules containing purified beta-carotene or a placebo (simple lactose). The study was conducted in a randomized and placebo-controlled design. After a depletion period of 14 days, 48 smokers were supplemented with either carrot juice (n = 18), purified beta-carotene (n = 16) or placebo (n = 14). Each group was supplemented for 8 weeks with approximately 20.49 mg of beta-carotene/day and 1.2 mg of vitamin C/day, as carrot juice (300 ml/day) or purified beta-carotene (20.49 mg of beta-carotene, 1 capsule/day). Lymphocyte DNA damage was determined using the COMET assay under alkaline conditions and damage was quantified by measuring tail moment (TM), tail length (TL), and% DNA in the tail. Lymphocyte DNA damage was significantly decreased in the carrot juice group in all three measurements. The group that received purified beta-carotene also showed a significant decrease in lymphocyte DNA damage in all three measurements. However, no significant changes in DNA damage was observed for the placebo group except TM (P = 0.016). Erythrocyte antioxidant enzyme was not significantly changed after supplementation. Similarly plasma lipid profiles were not different after carrot juice, beta-carotene and placebo supplementation. These results suggest that while the placebo group failed to show any protective effect, carrot juice containing beta-carotene or purified beta-carotene itself had great antioxidative potential in preventing damage to lymphocyte DNA in smokers.
beta Carotene ; Capsules ; Comet Assay ; Daucus carota ; DNA ; DNA Damage ; Erythrocytes ; Fruit ; Lymphocytes ; Plasma ; Vegetables ; Vitamins

Animals ; Comet Assay ; DNA Damage ; drug effects ; Lymphocytes ; drug effects ; Male ; Organometallic Compounds ; toxicity ; Rats

OBJECTIVETo investigate the genetic instability in patients with Dyskeration congenita.

METHODSThe spontaneous chromosome instability of lymphocytes from 4 DC patients, 29 FA patients and 24 healthy volunteers was assessed with comet assay. The percent of DNA in comet head (HeadDNA%）, the percent of DNA in comet tail (TailDNA%）, tail moment (TM), olive tail moment (OTM), the comet cell percentage (CCP) were compared between groups. And the results of MMC test, PNH clones and karotype were analysed additionally. The correlation between TM, OTM, CCP and the severity degree of bone marrow failure in DC group were evaluated.

RESULTS①PNH clones and karotype abnormalities were not found in 4 DC patients. ②TM (6.77 ± 0.90), OTM（6.19 ± 0.80) and CCP [(46.00 ± 5.03) %] in DC were significantly higher than those in normal control group [0.61 ± 0.49, 0.66 ± 0.42, (5.91 ± 3.19)%, P<0.05], however, not distinguished from FA patients [7.81 ± 3.58, 6.65 ± 2.21, (56.03 ± 13.47) %, P ≥ 0.05]. The aberrant cell percent at the MMC concentration of 80 μg/L in DC group was significantly lower than that in FA group [(21.00 ± 3.16) % vs (31.97 ± 6.33)%, P=0.003]. ③The correlation between TM, OTM, CCP and the severity of bone marrow failure in DC group were not found (P>0.05).

CONCLUSIONDC patients were of significantly increased genetic instability and normal DNA repair, which was different from that in FA patients. And there was no correlation between the degree of genetic instability and the severity of bone marrow failure in DC patients presenting as aplastic anemia.

Case-Control Studies ; Chromosomal Instability ; Comet Assay ; Dyskeratosis Congenita ; genetics ; Fanconi Anemia ; genetics ; Humans ; Lymphocytes ; Pancytopenia

OBJECTIVEThis paper aims to evaluate the genotoxicity in peripheral blood lymphocytes of rats after exposure to sunlight at different time points of day in a tropical region of Brazil (5 degrees S, 42 degrees W).

MATERIALS AND METHODSThirty Wistar-Hannover rats, three months old, were randomly divided into three groups of 10 animals each: Group I [control, without exposure to ultraviolet (UV) radiation], Group II (exposed to sunlight during 08:00 a.m. to 10:00 a.m.), and Group III (exposed to sunlight during 10:00 a.m. to 12:00 a.m.). After a week of exposure, peripheral blood samples were taken from the tail of these animals to prepare smears on two slides per animal. In 24 h after exposure to sunlight in Group III, a new collection was obtained to observe the repair activity. The alkaline comet assay was used in this study to evaluate the genotoxic activity of sunlight (P < 0.05).

RESULTSThere was no statistical difference between Group I and II (P = 0.672). On the other hand, the exposure to sunlight in Group III showed genotoxic action in comparison to the other groups (P < 0.0001). Also, there was no significant repair in Group III R (P = 0.407).

CONCLUSIONThis study has shown a genotoxic potential of sunlight (UVA-B) in lymphocytes of mammals from 10:00 a.m. to 12:00 a.m., due to a higher intensity of UV in this tropical region.

Animals ; Comet Assay ; DNA Damage ; Lymphocytes ; radiation effects ; Rats ; Rats, Wistar ; Sunlight

Adult ; Antineoplastic Agents ; adverse effects ; Comet Assay ; DNA Damage ; Female ; Humans ; Nurses ; Occupational Exposure ; Young Adult