丙烯酰胺致大鼠DNA损伤及多不饱和脂肪酸的拮抗效应

%均高于对照组,而丙烯酰胺染毒+EPA和DHA组大鼠周围血淋巴细胞、肝细胞、肺细胞及脑细胞尾长、尾DNA%与对照组相比变化不明显.结论 丙烯酰胺可致大鼠多组织细胞DNA损伤,EPA和DHA可拮抗这种损伤.     

气态苯染毒对大鼠多组织细胞DNA损伤作用

目的建立气态苯动式吸入染毒大鼠的实验模型,探讨苯所致大鼠多组织细胞DNA损伤作用,同时为室内装修污染对人体健康的潜在危害提供早期灵敏的生物标志物。方法苯吸入染毒组(处理组)大鼠每天吸入苯浓度为106 mg.m-3的空气4 h,连续7 d,染毒结束后,分别取外周血、脑、肺和肝组织并分离活细胞,应用彗星实验检测各组织细胞的DNA损伤情况,以DNA移动距离(慧星尾长)来表示损伤程度,其结果与空白对照组比较。结果彗星实验发现,处理组肝细胞、脑细胞和外周血淋巴细胞DNA移动距离均大于对照组(P<0.05);在加入蛋白酶K(PK)孵化后,处理组肺细胞、脑细胞、外周血淋巴细胞DNA移动距离的增加量与对照组比较,差异无统计学意义(P>0.05);而肝细胞经过PK孵化后,处理组细胞DNA移动距离的增加量显著高于对照组(P<0.05)。结论在此种染毒剂量下苯可致大鼠肺细胞、脑细胞和外周血淋巴细胞发生DNA断裂损伤,苯致上述细胞DNA发生DNA蛋白质交联的能力很弱,或者不产生DNA蛋白质的交联。而苯所致肝细胞DNA损伤方式以DNA-蛋白质交联为主。     

正己烷致大鼠外周血有核细胞DNA损伤的实验研究

目的研究正己烷(n-Hexane)对大鼠外周血有核细胞DNA损伤的影响,为其遗传毒性的研究提供实验数据。方法40只雄性Sprague-Dawley(SD)大鼠随机分成5组,即低(75 mg/kg)、中(150 mg/kg)、高300 mg/kg)剂量染毒组,阴性对照组和阳性对照组(环磷酰胺),每组8只。经腹腔注射正己烷,染毒4周后,观察大鼠的一般状况和体重变化,用彗星试验技术(SCGE)检测大鼠外周血有核细胞DNA的损伤。结果各组大鼠体重均持续增加,但高剂量组较对照组增长缓慢,差异有统计学意义(P<0.05)。各染毒组动物无明显中毒症状。外周血有核细胞SCGE检测彗星尾长、尾DNA%、尾矩、Olive尾矩均增大。阳性对照组尾长(63.84±19.79)、尾DNA%(28.78±6.99)、尾矩(15.47±8.60)、Olive尾矩(10.60±4.89)分别与阴性对照组比较,差异均有统计学意义(P<0.01)。低、中、高剂量组与阴性对照组比较,尾长、尾DNA%差异有统计学意义(P<0.05,P<0.01)。中、高剂量组与阴性对照组比较,尾矩,Olive尾矩差异有统计学意义(P<0.05,P<0.01)。尾矩值与染毒剂量作相关分析,相关系数r为0.978,呈正相关(P<0.05)。结论正己烷可使大鼠外周血有核细胞DNA发生损伤,具有一定的遗传毒性。     

低剂量辐射联合环磷酰胺对荷瘤鼠DNA损伤的影响

目的研究低剂量辐射联合环磷酰胺对荷瘤鼠外周血淋巴细胞DNA损伤的影响。方法荷瘤鼠随机分为对照组、CTX化疗组(CTX组,40mg/kg)和低剂量照射联合CTX组(LDR CTX组),环磷酰胺给予前6h行5cGy的低剂量照射,连续3 d。采用中性单细胞凝胶电泳检测低剂量辐射联合化疗后对荷瘤鼠外周血淋巴细胞DNA双链断裂的情况。观察了尾长、彗星长、头DNA%、尾DNA%、尾矩、Olive尾矩等指标的变化。结果LDR CTX组其尾长、彗星长、头DNA%、尾DNA%、尾矩、Olive尾矩均比CTX组明显减小,各项指标差异均有显著性(P<0.05)。结论荷瘤鼠预先接受低剂量全身照射能减轻环磷酰胺治疗后外周血淋巴细胞DNA损伤。     

氯乙烯致大鼠DNA损伤与肝代谢酶活性动态变化的研究

[目的]研究氯乙烯(VC)对大鼠肝细胞和外周血淋巴细胞DNA的损伤作用，及对VC代谢酶[谷胱甘肽硫转移酶(GST)、细胞色素P4502E1(CYP2E1)、乙醇脱氢酶(ADH)和乙醛脱氢酶(ALDH)]活性的影响；探索VC所致损伤的早期敏感检测指标。[方法]大鼠染毒12周，分别在第3、6、9和12周处死动物，DNA损伤采用单细胞凝胶电泳(彗星试验)法，代谢酶活性测定采用分光光度法。[结果]彗星细胞数目随染毒剂量和染毒时间的增加而增加，肝细胞DNA损伤细胞百分率第12周中剂量组和高剂量组分别为12.38％和17.88％，外周血淋巴细胞DNA损伤细胞百分率第3周高剂量组为7．33％，第12周中剂量组和高剂量组分别为16．25％和28、25％，均显著高于相应对照组，彗星细胞发生率与VC染毒剂量间存在显著相关关系。ALDH和CYP2E1活性随染毒时间和染毒剂量的增加发生改变，差异具显著性。肝细胞DNA损伤与CYP2EI活性相关。[结论]VC可导致肝细胞和外周血淋巴细胞DNA发生损伤，且存在剂量．反应和时间一效应关系；VC致肝细胞DNA损伤与CYP2E1代谢酶活性相关。彗星细胞率可作为VC所致肝脏损伤的早期检测指标。     

CS_2致大鼠睾丸Sertoli细胞DNA损伤的研究

目的研究CS2对离体培养大鼠睾丸Sertoli细胞DNA的损伤作用。方法从大鼠睾丸组织中分离Sertoli细胞进行离体原代培养、纯化及鉴定,用不同浓度(0、0.36、0.72和1.44μmol/ml)CS2染毒,应用SCGE检测CS2诱导Sertoli细胞DNA损伤,以彗星尾DNA%和Olive尾距反映DNA损伤水平。结果染毒组Sertoli细胞呈彗星状,尾DNA%[(13.91±3.23)、(37.07±5.42)和(49.10±5.26)]和Olive尾距[(3.71±1.66)、(11.73±2.65)和(19.54±3.41)]随CS2染毒浓度的增高而逐渐增高,与阴性对照组比较差异均有显著性(P<0.01),且与剂量对数呈明显的剂量-效应关系。结论CS2可诱导大鼠睾丸Sertoli细胞DNA损伤。     

甲醛吸入染毒对小鼠DNA损伤的影响

目的探讨甲醛吸入染毒对小鼠脾、肝、肺和肾组织细胞DNA的损伤作用。方法将40只健康昆明种小鼠随机分为5组,混合物静式吸入染毒,用不同剂量(0.0、0.75、1.5、3.0、6.0mg/m3)的甲醛染毒小鼠2周,第15天处理动物后,取脾、肝、肺、肾组织制成细胞悬液,用单细胞凝胶电泳实验观察其细胞DNA损伤水平。结果染毒后小鼠脾、肝、肺、肾组织细胞DNA出现损伤,且损伤程度与染毒剂量具有一定相关性。与空白对照组比较,3种组织细胞各剂量组细胞DNA拖尾率和彗星尾长均显著增加;随着甲醛染毒浓度的升高,脾、肝、肺和肾细胞拖尾率和彗星尾长增加。结论甲醛可引起小鼠的脾、肝、肺、肾组织细胞DNA损伤。     

甲醛对大鼠组织细胞DNA的损伤作用

目的探讨甲醛对大鼠肝、肾、肺组织细胞DNA损伤作用。方法将24只健康SD大鼠随机分为6组,用蒸馏水及不同剂量（10、20、30、40mg／kg）的甲醛溶液和环磷酰胺经腹腔染毒阴性对照组、染毒组和阳性对照组大鼠,第2天处理动物后,取肝、肾、肺组织用单细胞凝胶电泳实验观察其细胞DNA损伤水平。结果甲醛对大鼠的肝、肾、肺组织细胞DNA具有损伤作用,染毒剂量和损伤呈现一定的剂量一反应关系。随着甲醛染毒浓度的升高,肾、肺、肝细胞拖尾率增加,头尾比降低。结论甲醛可引起大鼠的肝、肾、肺组织细胞DNA损伤,从而进一步证实甲醛具有遗传毒性。     

钇对大鼠外周血淋巴细胞DNA损伤作用

目的 研究长期摄入稀土Y3 对大鼠外周血淋巴细胞DNA的损伤作用,为明确稀土的遗传毒性提供数据.方法 刚断乳大鼠分别饮用含稀土Y3 为0,53.4,5 340mg/L的饮用水,子代饮水同亲代.子代喂饮6个月后采用单细胞凝胶电泳(SCGE)技术观察大鼠外周血淋巴细胞DNA的损伤状况.结果 53.4和5 340 mg/L组大鼠淋巴细胞DNA形成的彗星尾部DNA含量、尾长、彗星长、Olive尾矩等指标均高于对照组.其中,低剂量组的彗星长(28.80±5.01)、高剂量组尾长(3.04±0.20)和彗星长(28.52±5.18)比较,差异有统计学意义(P＜0.05).结论 稀土 Y3 可造成大鼠外周血淋巴细胞DNA的损伤,有一定的遗传毒性.     

丙烯酰胺对小鼠脏器细胞DNA损伤及修复作用

目的研究丙烯酰胺的遗传毒性,探测其遗传毒性的靶器官。方法应用彗星试验检测50mg/kg丙烯酰胺腹腔注射染毒0、3、6、12和24h后小鼠肺、肝、脾、肾、睾丸、骨髓和外周血淋巴细胞的DNA损伤情况。结果丙烯酰胺染毒后不同时间,可引起小鼠肝、脾、睾丸、骨髓和外周血淋巴细胞彗星尾长、尾部DNA百分含量及尾矩的显著增加,随时间延长有下降趋势;未观察到对肺和肾脏细胞的明显影响。结论丙烯酰胺可以诱导小鼠多种组织细胞的DNA损伤,机体对丙烯酰胺造成的遗传损伤有一定的修复能力。     

Omega-3 Index and sudden cardiac death

Sudden cardiac death (SCD) is an unresolved health issue, and responsible for 15% of all deaths in Western countries. Epidemiologic evidence, as well as evidence from clinical trials, indicates that increasing intake and high levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) protect from SCD and other major adverse cardiac events. Levels of EPA+DHA are best assessed by the Omega-3 Index, representing the red cell fatty acid content of EPA+DHA. Work is in progress that will further define the value of the Omega-3 Index as a risk factor for SCD, other cardiac events, and as target for treatment with EPA+DHA.     

Effects of Eicosapentaenoic Acid and Docosahexaenoic Acid on Uncoupling Protein 3 Gene Expression in C2C12 Muscle Cells

Uncoupling protein 3 (UCP3) is a mitochondrial membrane transporter that is expressed mainly in skeletal muscle where it plays an important role in energy expenditure and fat oxidation. In this study, we investigated the effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on UCP3 gene expression in C₂C₁₂ muscle cells. EPA and DHA up-regulated UCP3 mRNA level in a dose-dependent manner and similarly increased UCP3 promoter activity in C₂C₁₂ muscle cells. To determine whether AMP-activated protein kinase (AMPK) signaling may also directly regulate UCP3 expression, 5′-amino-4-imidazolecarboxamide-ribonucleoside (AICAR), an AMP analog that activates AMPK, was treated in C₂C₁₂ muscle cells. AICAR showed additive effects with EPA or DHA on the UCP3 promoter activation. These results indicate that EPA and DHA directly regulate the gene expression of UCP3, potentially through AMPK-mediated pathway in C2C12 muscle cells.     

Effects of Long-Term Oral Administration of Arachidonic Acid and Docosahexaenoic Acid on the Immune Functions of Young Rats

Natural killer (NK) cells have many functional activities, including cytotoxicity and the capacity to produce cytokines and chemokines. NK cell activity is regulated partly by eicosanoids, which are produced from arachidonic acid (ARA) and eicosapentaenoic (EPA) acid. In this study, we investigated the effects of long-term therapy with ARA or docosahexaenoic acid (DHA) on the cytotoxic effects of the NK cells of young rats, which were fed on a nonfish oil diet for two generations. Control oil, ARA (240 mg/kg BW/day) or DHA (240 mg/kg BW/day) were orally administrated to the rats for 13 weeks before determining the cytotoxic activity of NK cells from the spleen against YAC-1 mouse lymphoma cell line, as well as the plasma levels of docosanoids or eicosanoids and inflammatory cytokines. Long-term ARA administration significantly suppressed the cytotoxic activity of NK cells. Moreover, ARA administration significantly increased the plasma levels of ARA, prostaglandin (PG) E₂, and PGD₂. However, DHA administration did not produce any different effects compared with those in the control rats. Furthermore, the inflammatory cytokine levels were not affected by the administration of ARA or DHA. These results suggest that long-term ARA administration has an inhibitory effect on the tumor cytotoxicity of NK cells in rat spleen lymphocytes owing to the enhanced synthesis of PGE₂ and PGD₂ from ARA because of the elevated plasma ARA levels in young rats.     

Docosahexaenoic Acid Induces Growth Suppression on Epithelial Ovarian Cancer Cells More Effectively than Eicosapentaenoic Acid

Omega-3 fatty acids, especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have been shown to possess definitively suppressive effects on the growth of epithelial ovarian cancer cells. This study investigated the differential effects of pure EPA and DHA on the growth of epithelial ovarian cancer cells and the potential molecular mechanisms that may be involved. There were significant time- and dose-dependent inhibitory effects of both EPA and DHA on cellular proliferation of the epithelial ovarian cancer cell line TOV-21G (P < 0.05). TOV-21G cells pretreated with peroxisome proliferator receptor activator gamma (PPARγ) antagonist, GW9662, markedly suppressed EPA/DHA-induced apoptosis as determined by TUNEL assay, Annexin V-FITC/PI staining, and caspase-3 activity. EPA/DHA significantly induced PPARγ and p53 overexpression as observed in immunoblotting assay and the induction of p53 by EPA/DHA was abolished by GW9662. In all cases, the effect of DHA was significantly more potent than that of EPA (P < 0.05). Our findings suggested that DHA may be more effective than EPA in growth suppression of TOV-21G cells and the biologic effects may be partly mediated by PPARγ and p53 activation. Further research is required to elucidate additional divergent mechanisms to account for apparent differences between EPA and DHA.     

Dietary n-3 polyunsaturated fatty acids increase oxidative stress in rats with intracerebral hemorrhagic stroke

Intake of n-3 polyunsaturated fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) has been suggested to associate with an increased risk of hemorrhagic stroke. The present study was designed to investigate the hypothesis that EPA and DHA increase oxidative stress and hemorrhage volume in rats with intracerebral hemorrhagic (ICH) stroke. Thirty-five-week-old male rats were fed an American Institute of Nutrition–93M diet containing 0% (n = 27), 0.5% (n = 15), or 1% EPA + DHA of total energy for 5 weeks. Of 5 rats fed 1% EPA + DHA (41%), 5 died because of excessive bleeding within 12 hours after ICH surgery. Behavior test score and hemorrhage volume were significantly (P < .05) greater in the 1% EPA + DHA–fed rats than in other rats. Magnetic resonance imaging consistently showed that edema and bleeding were visible in only the rats fed 1% EPA + DHA. Levels of superoxide dismutase and glutathione were significantly (P < .05) lower in rats fed 0.5% and 1% EPA + DHA than those fed 0% EPA + DHA. Thiobarbituric acid–reactive substance content was significantly (P < .05) higher in 1% EPA + DHA–fed rats than in 0% and 0.5% EPA + DHA–fed rats. The level of 8-hydroxydeoxyguanosine was significantly (P < .05) higher in ICH rats with all diets than in sham surgery rats. Brain levels of EPA and DHA were highest in rats fed 1% EPA + DHA than in rats fed 0% and 0.5% EPA + DHA. These results suggested that intake of 1% EPA + DHA of total energy could lead to oxidative damage to the brain and thus increase the risk of intracerebral hemorrhagic stroke in this rat model.     

A method for assessing dietary intakes of n-3 long-chain polyunsaturated fatty acids and trans fatty acids in an Irish adult population

Abstract

The present study aimed to quantify dietary intakes of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and trans fatty acids (trans FA) in Irish adults using the North/South Ireland Food Consumption Survey (NSIFCS). To update the NSIFCS database, specific approaches were necessary to select accurate data. Published references were the main data source used to update for EPA and DHA (21.7%), while the UK Nutrient Databank was most frequently used to update for trans FA (46.7%). Total EPA and DHA mean daily intake was 275 mg/day whilst trans FA mean daily intake was 0.72% food energy. Younger adults had significantly lower intakes of EPA and DHA than older adults. The present study shows that dietary EPA and DHA intakes in the Irish adult population are below recommendations, especially among the younger population. Conversely, trans FA intakes are within the recommended value of < 2% food energy.     

Effects of highly concentrated omega-3 polyunsaturated fatty acids and acetylsalicylic acid, alone and combined, on bleeding time and serum lipid profile

Twenty-two patients with stable coronary heart disease were randomly assigned to either of two groups. Group I (n = 11) was given acetylsalicylic acid (ASA) 300 mg daily for 1 week, whereafter a daily supplement of 3,4 g eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) as a highly concentrated ethylester, formulation ("K-85", Norsk Hydro) was added for another 4 weeks. Group II (n = 11) was given 3,4 g daily of EPA and DHA for 4 weeks, after which ASA 300 mg daily was added for another week. Determination of serum fatty acids confirmed satisfying absorption of EPA and DHA. A significant increase of the Ivy bleeding time was registered following administration of both "K-85" (240 to 270 sec, median values) and ASA (270 to 360 sec, median values) alone. A slighter increase was noted by a combination of the two principles. A reduction in serum triglycerides of 17% was noted after "K-85" (median values, both groups). Serum total cholesterol decreased after "K-85" administration in group I, but not so in group II. HDL-cholesterol remained unchanged. Serum lipids remained unaffected by ASA. During administration of "K-85" no adverse effects or bleeding episodes were seen.     

A polyunsaturated fatty acid diet lowers blood pressure and improves antioxidant status in spontaneously hypertensive rats

gamma-Linolenic acid [GLA, 18:3(n-6)], eicosapentaenoic acid [EPA, 20:5(n-3)] and docosahexaenoic acid [DHA, 22:6(n-3)] have been reported to prevent cardiovascular diseases. However, they are highly unsaturated and therefore more sensitive to oxidation damage. We investigated the effects of a diet rich in these polyunsaturated fatty acids (PUFA) on blood pressure, plasma and lipoprotein lipid concentrations, total antioxidant status, lipid peroxidation and platelet function in spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto rats (WKY). Five-week-old SHR and WKY rats were fed for 10 wk either a diet containing Isio 4 oil or a diet rich in GLA, EPA and DHA (5.65, 6.39 and 4.94 g/kg dry diet, respectively). The total antioxidant status was assayed by monitoring the rate of free radical-induced hemolysis. VLDL-LDL sensitivity to copper-induced lipid peroxidation was determined as the production of thiobarbituric acid reactive substances. After dietary PUFA supplementation, a significant decrease in blood pressure of SHR rats (-20 mm Hg) was observed and the total antioxidant status was enhanced. VLDL-LDL resistance to copper-induced peroxidation was increased in both strains. The PUFA supplementation did not change platelet maximum aggregation in SHR rats, but it decreased the aggregation speed. In hypertensive rats, GLA + EPA + DHA supplementation lowers blood pressure, enhances total anti-oxidant status and resistance to lipid peroxidation, diminishes platelet aggregation speed and lowers plasma lipid concentrations. Thus, it enhances protection against cardiovascular diseases. Therefore, nutritional recommendations for cardiovascular disease prevention should take into account the pharmacologic properties of GLA, EPA and DHA.     

DHA预防百草枯诱导大鼠肺组织Smad7和SnoN表达的降低

目的观察百草枯(paraquate,PQ)对大鼠肺组织中Smad7和SnoN蛋白表达的影响和DHA的干预作用。方法体重200～220g的SPF级雄性Wistar大鼠40只,随机分为4组:正常对照组、模型组、DHA干预组和DHA对照组,每组10只。DHA干预组和DHA对照组,分别经灌胃给予DHA(500mg/kg.bw),正常对照组和模型组给予等体积玉米油,给予DHA第8日,DHA干预组和模型组一次性经灌胃给予50mg/kg.bw PQ染毒,正常对照组和DHA对照组均给予等体积生理盐水。PQ染毒后,持续给予DHA,于染毒后第35日,处死动物,取出肺组织,制备组织匀浆,测定还原性谷胱甘肽(glutathione,GSH)含量,同时制备肺组织切片,免疫组织化学方法观察肺组织中Smad7及SnoN蛋白表达情况。结果各组肺组织中GSH含量无显著差异(P>0.05);与正常对照组比较,模型组大鼠肺组织中Smad7,SnoN蛋白表达水平显著下降(P<0.01,P<0.01);DHA干预组大鼠肺组织中Smad7,SnoN蛋白表达水平明显高于模型组(P<0.01,P<0.05),与正常对照组无显著差别(P>0.05)。结论 DHA能够逆转PQ诱导肺纤维化负向调节因子Smad7和SnoN的减少,对PQ导致的肺组织损伤具有一定的预防性保护作用。     

Docosahexaenoic Acid (DHA), a Primary Tumor Suppressive Omega-3 Fatty Acid,Inhibits Growth of Colorectal Cancer Independent of p53 Mutational Status

Human colon carcinoma COLO 205, carrying wild type p53, grown subcutaneously in athymic mice was inhibited 80% by a high fat menhaden oil diet containing a mixture of omega-3 fatty acids compared to the low fat corn oil diet containing omega-6 fatty acids. Feeding a high fat diet of golden algae oil containing docosahexaenoic acid (DHA) as the sole long chain omega-3 fatty acid resulted in 93% growth inhibition. Similar findings were previously reported for WiDr colon carcinoma containing mutated p53 (His237). In vitro, 125 μM DHA inhibited COLO 205 growth by 81%, WiDr by 42%, while eicosapentaenoic acid (EPA) marginally inhibited growth of both lines by approximately 30%. DHA inhibited cell proliferation by 41% in WiDr but did not significantly inhibit proliferation in COLO 205. Cell cycle analysis revealed that DHA arrested cell cycle at Resting/Gap 1 (G0/G1 phase) in WiDr and at Gap 2/Mitosis (G2/M) phase in COLO 205. DHA induced apoptosis in COLO 205 but not in WiDr, and EPA did not induce apoptosis in either line. Taken together, these findings suggest DHA is the primary tumor suppressive ω-3 fatty acid in vivo and in vitro and inhibits cancer growth by p53 dependent and independent pathways, while the marginal inhibition by EPA is p53 independent.