Genotoxicity of waterpipe smoke in buccal cells and peripheral blood leukocytes as determined by comet assay

Abstract

Context: Waterpipe smoke causes DNA damage in peripheral blood leukocytes and in buccal cells of smokers.

Objective: To determine the exposure effect of waterpipe smoke on buccal cells and peripheral blood leukocytes in regard to DNA damage using comet assay.

Materials and methods: The waterpipe smoke condensates were analyzed by gas chromatography-mass spectrometry (GC-MS). The study was performed on 20 waterpipe smokers. To perform comet assay on bucaal cells of smokers, 10?µl of cell suspension was mixed with 85?µl of pre-warmed 1% low melting agarose, applied to comet slide and electrophoresed. To analyze the effect of smoke condensate in vitro, 1?ml of peripheral blood was mixed with 10?µl of smoke condensate and subjected for comet assay.

Results: The GC-MS analysis revealed the presence of 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4on, nicotine, hydroxymethyl furancarboxaldehyde and 3-ethoxy-4-hydroxybenzaldehyde in the smoke condensates. Waterpipe smoking caused DNA damage in vivo in buccal cells of smokers. The tail moment and tail length in buccal cells of smokers were 186?±?26 and 456?±?71, respectively, which are higher than control. The jurak and moassel smoke condensates were found to cause DNA damage in peripheral blood leukocytes. The moassel smoke condensate was more damaging.

Discussion: There is wide misconception that waterpipe smoking is not as harmful as cigarette smoking. This study demonstrated that waterpipe smoke induced DNA damage in exposed cells.

Conclusion: Waterpipe smokes cause DNA damage in buccal cells. The smoke condensate of both jurak and moassel caused comet formation suggesting DNA damage in peripheral blood leukocytes.     

Prevention of arsenic-mediated reproductive toxicity in adult female rats by high protein diet

Abstract

Context: The detrimental effects of arsenic on female reproductive functions may involve overt oxidative stress. Casein and pea [Pisum sativum Linn. (Fabaceae)] proteins have antioxidant properties.

Objective: To investigate the role of casein- and pea-supplemented high-protein diet (HPD) in utero-ovarian protection from arsenic toxicity.

Materials and methods: Adult female Wistar rats were orally gavaged with vehicle (Gr-I) or arsenic at 3?ppm/rat/d (Gr-II and Gr-III) for 30 consecutive days, when they were maintained on either regular diet containing 18% protein (Gr-I and Gr-II), or HPD containing 27% protein in the form of casein (20%) and pea (7%) (Gr-III). Reproductive functions were evaluated using a battery of biochemical and histological techniques.

Results: As compared to Gr-I, the Gr-II rats suffered from loss of estrous cyclicity, reduction in weight (mg/100?g body weight) of ovary (Gr-I: 54.3?±?4.2 versus Gr-II: 35.8?±?1.6; p?<?0.001) and uterus (Gr-I: 161.7?±?24.6 versus Gr-II: 94.44?±?13.2; p?<?0.05), utero-ovarian degeneration, attenuated ovarian activities (unit/mg tissue/h) of Δ⁵, 3β-hydroxysteroid dehydrogenase (Gr-I: 3.41?±?0.12 versus Gr-II: 2.31?±?0.09; p?<?0.01) and 17β-hydroxysteroid dehydrogenase (Gr-I: 3.82?±?0.57 versus Gr-II: 1.24?±?0.19; p?<?0.001), and decreased serum estradiol level (pg/ml) (Gr-I: 61.5?±?2.06 versus 34.1?±?2.34; p?<?0.001). Ovarian DNA damage was preponderant with blatant generation of malondialdehyde (nM/mg tissue; Gr-I: 15.10?±?2.45 versus Gr-II: 29.51?±?3.44; p?<?0.01) and attenuated superoxide dismutase activity (unit/mg tissue) (Gr-I: 2.18?±?0.19 versus Gr-II: 1.33?±?0.18; p?<?0.05). The Gr-III rats were significantly protected from these ill effects of arsenic.

Discussion and conclusion: HPD, by way of antioxidant properties, may find prospective role in the protection of reproductive damage caused by arsenic.     

Cytotoxic,Genotoxic and Senolytic Potential of Native and Micellar Curcumin

Background: Curcumin, a natural polyphenol and the principal bioactive compound in Curcuma longa, was reported to have anti-inflammatory, anti-cancer, anti-diabetic and anti-rheumatic activity. Curcumin is not only considered for preventive, but also for therapeutic, purposes in cancer therapy, which requires a killing effect on cancer cells. A drawback, however, is the low bioavailability of curcumin due to its insolubility in water. To circumvent this limitation, curcumin was administered in different water-soluble formulations, including liposomes or embedded into nanoscaled micelles. The high uptake rate of micellar curcumin makes it attractive also for cancer therapeutic strategies. Native curcumin solubilised in organic solvent was previously shown to be cytotoxic and bears a genotoxic potential. Corresponding studies with micellar curcumin are lacking. Methods: We compared the cytotoxic and genotoxic activity of native curcumin solubilised in ethanol (Cur-E) with curcumin embedded in micells (Cur-M). We measured cell death by MTT assays, apoptosis, necrosis by flow cytometry, senolysis by MTT and C12FDG and genotoxicity by FPG-alkaline and neutral singe-cell gel electrophoresis (comet assay). Results: Using a variety of primary and established cell lines, we show that Cur-E and Cur-M reduce the viability in all cell types in the same dose range. Cur-E and Cur-M induced dose-dependently apoptosis, but did not exhibit senolytic activity. In the cytotoxic dose range, Cur-E and Cur-M were positive in the alkaline and the neutral comet assay. Genotoxic effects vanished upon removal of curcumin, indicating efficient and complete repair of DNA damage. For inducing cell death, which was measured 48 h after the onset of treatment, permanent exposure was required while 60 min pulse-treatment was ineffective. In all assays, Cur-E and Cur-M were equally active, and the concentration above which significant cytotoxic and genotoxic effects were observed was 10 µM. Micelles not containing curcumin were completely inactive. Conclusions: The data show that micellar curcumin has the same cytotoxicity and genotoxicity profile as native curcumin. The effective concentration on different cell lines, including primary cells, was far above the curcumin concentration that can be achieved systemically in vivo, which leads us to conclude that native curcumin and curcumin administered as food supplement in a micellar formulation at the ADI level are not cytotoxic/genotoxic, indicating a wide margin of safety.     

应用胞质分裂阻滞微核细胞组学法评价三溴乙酸的遗传毒性

[目的]应用胞质分裂阻滞微核细胞组学方法[cytokinesis-block micronucleus cytome（CBMN-cyt）assay]评价三溴乙酸的遗传毒性。[方法]以小鼠淋巴瘤（L5178Y）细胞为受试细胞,分为2组。一组暴露于终浓度分别为0（阴性对照）、7．81、15．62、31．25、62．50、125．00、175．00、250．00μg／mL的三溴乙酸溶液24h,采用噻唑蓝比色法（MTF法）检测细胞毒性,并计算半数致死浓度（medianlethaldose,LC50）;另一组暴露于终浓度分别为0（阴性对照）、31．25、62．50、125．00、175．00μg／mL的三溴乙酸溶液24h,并设阳性对照（终浓度为0．10μg／mL丝裂霉素C）,采用CBMN-cyt试验检测遗传毒性。[结果]与阴性对照组相比,31．25、62．50,125．00,175．00,250．00μg／mL三澳乙酸染毒组L5178Y细胞的存活率均较低,差异有统计学意义（P〈0．05）;且随着三溴乙酸染毒浓度的升高,L5178Y细胞的存活率呈明显的下降趋势（尸〈0．01）。三溴乙酸对该细胞的LC50为135．7μg／mL。与阴性对照比较,125．00、175．00μg／mL三溴乙酸染毒L5178Y细胞的微核率均升高,各浓度三溴乙酸染毒L5178Y细胞的核质桥率也均升高,差异有统计学意义（P〈0．05）;而各浓度三溴乙酸染毒L5178Y细胞的核芽率和核分裂指数（nucleusdividedindex,NDI）无显著改变。Pearson相关分析显示,随着三溴乙酸染毒剂量的升高,L5178Y细胞的微核率、核质桥率、核芽率均呈明显的上升趋势（P〈0．01）。[结论]三溴乙酸的遗传毒性,可能与染色体损伤、DNA错误修复、染色体重组或端粒末端融合损伤有关。     

Monitoring of DNA breakage in embryonic stages of the African catfish Clarias gariepinus (Burchell, 1822) after exposure to lead nitrate using alkaline comet assay

Increasing lead contamination in Egyptian ecosystems and high lead concentrations in food items have raised concern for human health and stimulated studies on monitoring ecotoxicological impact of lead-caused genotoxicity. In this work, the alkaline comet assay was modified for monitoring DNA strand breakage in sensitive early life stages of the African catfish Clarias gariepinus. Following exposure to 100, 300, and 500 microg/L lead nitrate, DNA strand breakage was quantified in embryos at 30, 48, 96, 144, and 168 h post-fertilization (PFS). For quantitative analysis, four commonly used parameters (tail % DNA, %TDNA; head % DNA, %HDNA; tail length, TL; tail moment, TM) were analyzed in 96 nuclei (in triplicates) at each sampling point. The parameter %TDNA revealed highest resolution and lowest variation. A strong correlation between lead concentration, time of exposure, and DNA strand breakage was observed. Here, genotoxicity detected by comet assay preceded the manifested malformations assessed with conventional histology. Qualitative evaluation was carried out using five categories are as follows: undamaged (%TDNA < or = 10%), low damaged (10% < %TDNA < or = 25%), median damaged (25 < %TDNA < or = 50%), highly damaged (50 < %TDNA < or = 75%), and extremely damaged (%TDNA > 75%) nuclei confirming a dose and time-dependent shift towards increased frequencies of highly and extremely damaged nuclei. A protective capacity provided by a hardened chorion is a an interesting finding in this study as DNA damage in the prehatching stages 30 h-PFS and 48 h-PFS was low in all treatments (qualitative and quantitative analyses). These results clearly show that the comet assay is a sensitive tool for the detection of genotoxicity in vulnerable early life stages of the African catfish and is a method more sensitive than histological parameters for monitoring genotoxic effects.     

补血益母丸遗传毒性研究

目的 对补血益母丸干膏粉进行遗传毒性试验,为临床安全用药提供依据。方法 采用组氨酸营养缺陷型鼠伤寒沙门氏菌TA97a、TA98、TA100、TA102、TA1535进行细菌回复突变（Ames）试验,采用中国仓鼠肺成纤维（CHL）细胞进行体外染色体畸变试验,采用ICR小鼠进行骨髓细胞微核试验综合评估补血益母丸干膏粉的遗传毒性。其中,Ames试验设50、150、500、1 500、5 000 μg·皿^-1 5个剂量;体外细胞染色体畸变试验设125、250、500 μg·mL^-1 3个剂量;小鼠骨髓细胞微核试验设500、1 000、2 000 mg·kg^-1 3个剂量,每天给药1次,连续给药3 d。结果 在代谢及非代谢活化条件下（＋S9/-S9）,Ames试验结果 显示,补血益母丸干膏粉对各菌株均无明显或可重复的诱变性及抑菌性;体外CHL细胞染色体畸变试验结果显示,补血益母丸干膏粉对CHL细胞染色体结构畸变率未见有意义的升高;小鼠骨髓细胞微核试验结果显示,补血益母丸干膏粉对ICR小鼠骨髓细胞微核率无明显影响。结论 补血益母丸干膏粉未见潜在的遗传毒性。     

In vivo exposure to microcystins induces DNA damage in the haemocytes of the zebra mussel, Dreissena polymorpha, as measured with the comet assay

The Comet assay was used to investigate the potential of the biotoxin microcystin (MC) to induce DNA damage in the freshwater zebra mussel, Dreissena polymorpha. Mussels maintained in the laboratory were fed daily, over a 21-day period, with one of four strains of the cyanobacterium, Microcystis aeruginosa. Three of the strains produced different profiles of MC toxin, while the fourth strain did not produce MCs. The mussels were sampled at 0, 7, 14, and 21 days by withdrawing haemocytes from their adductor muscle. In addition, a positive control was performed by exposing a subsample of the mussels to water containing cadmium chloride (CdCl(2)). Cell viability, measured with the Fluorescein Diacetate/Ethidium Bromide test, indicated that the MC concentrations, to which the mussels were exposed, were not cytotoxic to the haemocytes. The Comet assay performed on the haemocytes indicated that exposure to CdCl(2) produced a dose-responsive increase in DNA damage, demonstrating that mussel haemocytes were sensitive to DNA-damaging agents. DNA damage, measured as percentage tail DNA (%tDNA), was observed in mussels exposed to the three toxic Microcystis strains, but not in mussels exposed to the nontoxic strain. Toxin analysis of the cyanobacterial cultures confirmed that the three MC-producing strains exhibit different toxin profiles, with the two MC variants detected being MC-LF and MC-LR. Furthermore, the DNA damage that was observed appeared to be strain-specific, with high doses of MC-LF being associated with a higher level of genotoxicity than low concentrations of MC-LR. High levels of MC-LF also seemed to induce relatively more persistent DNA damage than small quantities of MC-LR. This study is the first to demonstrate that in vivo exposure to MC-producing strains of cyanobacteria induces DNA damage in the haemocytes of zebra mussels and confirms the sublethal toxicity of these toxins.     

Base excision repair pathway is involved in the repair of lesions generated by flavonoid-enriched fractions of pepper tree (Schinus terebinthifolius, Raddi) stem bark

Cell-free and bacterial assays indicate that flavonoid-enriched fractions and the flavonoids of pepper tree stem bark from Schinus terebinthifolius Raddi have genotoxic rather than antigenotoxic properties. In the present report, we have examined the ability of flavonoid-enriched fractions to damage plasmid DNA and the repair pathways involved in the recognition of these DNA lesions. High concentrations of two flavonoid-enriched fractions were able to break phosphodiester bonds in DNA. In addition, studies using bacterial strains deficient in nucleotide excision repair and base excision repair (BER) enzymes indicated that the flavonoid-enriched fractions generated lesions that were substrates for enzymes belonging to the BER pathway. In addition, in vitro studies indicated that the DNA damage produced by the flavonoid-enriched fractions was also a substrate for exonuclease III and that the phosphodiester breakage was amplified by copper ions. These results indicate that flavonoids from the pepper tree (Schinus terebinthifolius, Raddi) generate lesions on DNA that are potential targets of FPG and MutY glycosylase from the BER pathway. Chromatographic and spectral analyses helped to support the hypothesis that the flavonoids of the Brazilian pepper tree bark are the main factors involved in the fraction's damage potential. The isolated flavonoids from Fraction II were also tested in vitro and support the oxidative damage potential of these flavonoids.     

Acrolein-induced oxidative stress and genotoxicity in rats: protective effects of whey protein and conjugated linoleic acid

Acrolein (AC), a highly reactive hazardous pollutant, poses serious threats to human health. Whey protein (WP) and conjugated linoleic acid (CLA) have beneficial health implications. We investigated the protective effects of WP and CLA against AC-induced toxicity in rats. The animals were orally gavaged with CLA (200?mg/kg/day), WP (200?mg/kg/day), AC (5?mg/kg/day), CLA?+?AC (200?+?5?mg/kg/day), and WP?+?AC (200?+?5?mg/kg/day) six days per week for 30?days. The oral administration of AC significantly induced oxidative stress by increasing thiobarbituric acid reactive substances (TBARS) and protein carbonyls (PCOs) levels and decreasing glutathione (GSH) level in the spleen, thymus, and polymorphonuclear leukocytes (PMNs). It also increased the frequencies of micronucleus (MN) and megakaryocytic emperipolesis (ME) and decreased the ratio of polychromatic erythrocytes (PCEs) in bone marrow. Slight alterations in urinary 8-hydroxydeoxyguanosine (8-OHdG) levels were not significant. Co-treatment with CLA?+?AC or WP?+?AC ameliorated the values of oxidative stress, MN, PCE, and ME. These data suggest that CLA and WP can improve the antioxidant defenses and preclude the formation of genetic damage and ME.