银杏二萜内酯葡胺注射液通过抑制p38/p53通路保护氧糖剥夺SY5Y细胞的机制

目的探讨银杏二萜内酯葡胺注射液(diterpene ginkgolides meglumine injection,DGMI)对缺糖/缺氧损伤(oxygen-glucose deprivation,OGD)的人神经母细胞瘤细胞(SY5Y)保护的作用及可能的机制。方法 SY5Y细胞OGD损伤4 h后,予药物复氧1 h,然后测定细胞存活率(CCK-8法)、凋亡坏死比率、线粒体膜电位(ΔΨm);蛋白质免疫印迹检测细胞中p-p38、p-p53、Bcl-2、Bax和cleaved caspase-9、cleaved caspase-3蛋白量的变化。结果 DGMI能明显提高OGD损伤的SY5Y细胞的存活率,降低细胞凋亡比率,挽救下降的线粒体膜电位(ΔΨm)。下调p-p38、p-p53、Bax/Bcl-2、cleaved caspase-9、cleaved caspase-3等蛋白量,抑制p38和p53活性,保护神经细胞。结论DGMI对OGD损伤的SY5Y细胞具有明显的保护作用,其保护机制可能与细胞内p38/p53/Bcl-2/caspase-9/caspase-3信号通路的抑制有关。     

人支气管上皮细胞5-脂氧合酶介导4-氨基联苯的活化及DNA损伤

目的探讨人支气管上皮(HBE)细胞内5-脂氧合酶(5-LOX)对4-氨基联苯(4-ABP)的氧化活化及所致DNA损伤,为LOX作为前致癌物氧化活化的代谢途径提供依据。方法①体外酶系统实验:4-ABP在含有大豆脂氧合酶(SLO)的体外酶体系中反应,用分光光度法检测体系中反应产物生成。②细胞实验:4-ABP 100～800μmol.L-1染毒HBE细胞,MTT法检测HBE细胞存活率;Western印迹法检测5-LOX蛋白表达;单细胞凝胶电泳检测DNA损伤。同时,检测特异性5-LOX抑制剂AA861对5-LOX蛋白表达和多种酶抑制剂对细胞存活率和DNA损伤的影响。结果在过氧化氢参与下,SLO可以协同氧化4-ABP,LOX抑制剂去甲二氢愈创木酸可抑制该协同氧化作用。4-ABP可以使HBE细胞内5-LOX蛋白表达增加,AA861对5-LOX蛋白表达没有影响;4-ABP 400μmol.L-1可以使HBE细胞产生明显的DNA损伤,彗星细胞的阳性率达47.7%(P<0.01),AA861和萘普生可以抑制该浓度4-ABP所致的DNA损伤,最大保护率分别为58.1%和21.7%。结论 4-ABP上调HBE的5-LOX蛋白表达。5-LOX可能通过介导4-ABP协同氧化,导致DNA损伤,这可能是4-ABP致癌的机制之一。     

去甲基化机制在腺苷及同型半胱氨酸诱导肝癌HepG2细胞凋亡中的作用

目的探索去甲基化机制在腺苷(ADO)及同型半胱氨酸(HCY)诱导肝癌HepG2细胞凋亡中的作用。方法CCK8法检测不同浓度腺苷(1.0、2.0、4.0 mol·L-1)单独或者联合同型半胱氨酸作用肝癌HepG2细胞不同时间(6、12、24 h)后细胞存活率;亦使用DNA甲基化酶抑制剂5-AzaCdR观察其对细胞生长的影响。AnnexinV-FITC/PI双染法检测细胞凋亡率,流式细胞术检测细胞内线粒体膜电位:实时荧光定量PCR及Western免疫印迹法分别检测caspase-3、caspase-8、caspase-9、MDM-2、p53、Cytochrome C、DNMT1、DNMT3a、DNMT3b等因子的表达量。结果 ADO联合HCY明显抑制HepG2细胞增殖,呈剂量和时间依赖性;不同浓度ADO联合HCY(1.0、2.0、4.0 mol·L-1)作用HepG2细胞24h,细胞凋亡率分别为(18.63±1.25)%,(29.42±2.37)%,(42.47±3.09)%,均明显高于阴性对照组(1.30±0.82)%,P<0.01;联合用药组线粒体膜电位明显下降,分别从空白对照组(674.15±82.8)%下降为(428.38±54.5)%、(297.78±30.5)%、(74.45±5.73)%,P<0.01;ADO联合HCY导致caspase-3、caspase-8、caspase-9、p53、Cytochrome C表达上调,MDM-2表达下调。ADO联合HCY或5-Aza-CdR处理HepG2细胞均可抑制DNA(甲基化酶DNMT1、DNMT3a、DNMT3b)mRNA表达量。结论 ADO与HCY联合作用引起了细胞内甲基化改变,低甲基化作用激活了p53及线粒体等凋亡通路,最终导致肝癌HepG2细胞凋亡。     

栀子苷抗H_2O_2诱导人脐静脉内皮细胞凋亡的实验研究

目的探讨栀子苷对氧化应激诱导人脐静脉内皮细胞(HUVEC)凋亡的抑制作用及可能机制。方法体外培养的HUVEC细胞用不同浓度的栀子苷药物预处理24h后,加入终浓度为500μmol·L-1H2O2氧化损伤12h。荧光染色法观察细胞内DNA损伤情况,流式细胞术检测细胞凋亡率和线粒体膜电位的变化,Western blot检测Bcl-2和Bax蛋白的表达,酶免法测定caspase-3蛋白酶的活性,Real-time PCR检测超氧化物歧化酶(Mn-SOD)和谷胱甘肽过氧化物酶(GPx)的mRNA表达。结果与模型组相比,不同浓度栀子苷(12.5、25、50mg·L-1)可以明显改善H2O2对细胞内的DNA氧化损伤,降低细胞凋亡率,下调Bax蛋白表达,逐步恢复Bcl-2/Bax表达比例和线粒体膜电位的改变,降低caspase-3蛋白酶活性,上调细胞内Mn-SOD和GPx的表达,但对Bcl-2的表达无影响。结论栀子苷可以抑制H2O2诱导的HUVEC细胞凋亡,其机制可能与调节线粒体应激途径和发挥抗氧化损伤功能有关。     

8-羟基喹啉酮对HepG2细胞氧化性DNA损伤的诱导作用(英文)

目的评估8-羟基喹啉酮(CuQ)对HepG2细胞的DNA损伤作用并阐明其可能的作用机制。方法 CuQ 0～4μmol.L-1处理HepG2细胞不同时间后,通过单细胞凝胶电泳实验检测细胞DNA损伤;分光光度法测定过氧化氢酶活性;苯二醛法测定细胞内谷胱甘肽(GSH)水平;硫代巴比妥酸反应物(TBARS)法检测细胞内脂质过氧化水平;Western印迹法检测NF-κB p65的变化;免疫组化方法检测细胞内8-羟基脱氧鸟苷(8-OHdG)的表达水平。结果 HepG2细胞与CuQ 0.5～4μmol.L-1作用1 h后,DNA的迁移距离明显增加(P<0.05),提示CuQ可引起DNA链断裂。CuQ能够造成细胞内GSH水平以及过氧化氢酶活性的降低。随着CuQ剂量的增加及染毒时间的延长,NF-κB由细胞浆逐渐转移至细胞核。CuQ还可以引起细胞内TBARS水平增高及8-OHdG表达水平的增强。采用GSH合成特异抑制剂DL-甲硫氨酸磺酰亚胺(BSO)预处理细胞,可明显增强CuQ对HepG2细胞DNA的损伤(P<0.05)。结论 CuQ可造成HepG2细胞氧化性DNA损伤,其作用机制与氧化应激及NF-κB p65在细胞核蓄积增高有关。     

毛蕊花苷对MPP~+诱导的SHSY5Y细胞凋亡的保护作用

目的观察肉苁蓉提取物毛蕊花苷对MPP+诱导的SHSY5Y细胞损伤的影响。方法用MTT法检测细胞存活率,以流式细胞仪检测细胞内活性氧的产生和线粒体膜电位的变化,以及细胞凋亡的发生,并用荧光酶标仪测定caspase-3的活性,蛋白印迹测定Bcl-2的表达水平。结果200μmol·L-1MPP+处理细胞24h降低细胞的存活率;诱导细胞发生凋亡,凋亡率达38.9%;细胞内活性氧水平及caspase-3的活性升高;而线粒体膜电位却明显降低。而预先给予0.1、1或者10mg·L-1浓度的毛蕊花苷处理细胞12h,可提高细胞存活率;流式细胞仪检测凋亡率分别降低到29.5%,15.3%和8.6%,而且细胞内活性氧的水平明显降低,并可逐渐恢复线粒体的高能量状态;caspase-3的活性不断降低,Bcl-2的表达水平增高,并呈现一定的剂量依赖性。结论毛蕊花苷能抑制MPP+诱导的SHSY5Y细胞凋亡,其神经细胞保护作用可能与其降低细胞内活性氧水平,维持线粒体膜电位的高能状态和抑制caspase-3的活性有关。     

姜黄素对皮层神经元氧化损伤的保护作用

目的　观察姜黄素对第三丁基过氧化氢 (tert butylhy droperoxide,t BHP ,tBHP)诱导的大鼠皮层神经元氧化损伤的影响 ,探讨可能的机制。方法　培养胚胎鼠皮层神经元 ,MTT法测定细胞活力 ,DNA断裂评价细胞凋亡 ,流式细胞术测定线粒体膜电位和细胞内活性氧水平 ,分光光度法测定细胞内谷胱甘肽 (GSH)水平 ,Westernblot法测定Bcl 2和Bax蛋白和胞浆细胞色素C以及活化型半胱氨酸天冬氨酸蛋白酶 3(caspase 3)和多聚 (ADP 核糖 )聚合酶 [poly (ADP ribose)poly merase,PARP]水平。结果　姜黄素 (2 5～ 2 0 μmol·L-1)可有效减少tBHP对神经元的氧化损伤和tBHP引起的细胞内GSH水平降低 ,降低细胞内的活性氧水平 ,增加线粒体膜电位和细胞内GSH以及Bcl 2蛋白水平 ,减少线粒体内细胞色素C向胞浆释放和Bax蛋白表达水平 ,最终明显减少cas pase 3和PARP活化和tBHP引起的神经元凋亡。结论　姜黄素可减弱tBHP对原代皮层神经元的氧化损伤作用 ,其作用可能与降低细胞内的活性氧水平 ,保护线粒体功能有关     

葛根素通过神经酰胺通路抑制UVB诱导的HaCaT细胞DNA损伤

研究葛根素(puerarin,PUE)对UVB诱导的HaCaT细胞DNA损伤的影响和作用机制。葛根素预处理细胞以30 mJ.cm2 UVB照射,24 h后以彗星电泳实验检测DNA损伤,薄层色谱法和气相色谱法检测神经酰胺,流式细胞术检测细胞内游离钙离子,Western blotting法检测p38蛋白磷酸化水平。结果显示,UVB模型组细胞DNA损伤、细胞内游离钙离子、神经酰胺、磷酸化p38蛋白显著增加;与UVB模型组相比,各葛根素预处理组的DNA损伤、细胞内游离钙离子、神经酰胺、磷酸化p38蛋白均减少。结果表明,葛根素首先抑制神经酰胺蓄积,阻止下游的细胞内钙离子升高和p38 MAPK通路激活,从而减轻UVB诱导的HaCaT细胞DNA损伤。     

灵芝多糖肽对ECV304细胞氧化损伤的保护作用

目的研究灵芝多糖肽对ECV304氧化损伤的保护作用。方法培养ECV304细胞,以叔丁基氢过氧化物(tBOOH)为氧化剂损伤细胞,造成氧化损伤模型,培养液中加入不同浓度灵芝多糖(12.5、25、50、100mg.L-1),以MTT法测细胞存活率;以光镜、电镜检测细胞形态学改变及线粒体损伤;用AnnexinV/PI双标记细胞,流式细胞检测细胞凋亡的百分率。结果灵芝多糖(12.5、25、50、100mg.L-1)可减少叔丁基氢过氧化物对ECV304的氧化损伤,MTT检测灵芝多糖给药组,ECV304细胞存活率增加。光镜下可见细胞损伤减少,电镜可见灵芝多糖(50mg.L-1,温育24h)减轻细胞器如线粒体氧化损伤,减少细胞凋亡。细胞流式检测表明:对照组、给药组、损伤组总凋亡百分率分别2.24%±0.43%、24%±6.4%(P<0.01)、82.1%±7.9%。结论灵芝多糖肽(GLPP)对ECV304细胞氧化损伤具有保护作用。     

高脂通过线粒体通路诱导H9c2心肌细胞损伤

目的探讨高脂通过线粒体凋亡通路对H9c2心肌细胞的损伤作用。方法棕榈酸(0～0.4 mmol·L~(-1))刺激H9c2心肌细胞24 h和0.2 mmol·L~(-1)棕榈酸刺激H9c2心肌细胞(0～48 h);MTT法评估细胞生长状态;活性氧试剂盒检测细胞内活性氧水平;凋亡试剂盒检测细胞凋亡情况;线粒体膜电位试剂盒检测线粒体膜电位变化;免疫印迹法检测细胞内线粒体凋亡相关蛋白Cyt-C、Cleaved casepase-3、Bax、Bcl-2表达水平。结果棕榈酸刺激H9c2心肌细胞24 h,棕榈酸0.2、0.4 mmol·L~(-1)组细胞增殖率均出现明显下降;细胞内活性氧水平逐渐升高,线粒体膜电位下降,细胞凋亡增加。棕榈酸(0.2 mmol·L~(-1))刺激H9c2心肌细胞24、36、48 h均引起细胞增殖率明显下降。棕榈酸(0.4 mmol·L~(-1))刺激H9c2心肌24 h,线粒体相关蛋白Cyt-C、Cleaved casepase-3、Bax表达均明显增高(P <0. 05),而Bcl-2明显降低(P <0. 05)。结论线粒体凋亡信号通路可能对高脂所致H9c2心肌细胞损伤起重要作用。     

褪黑素对苯妥英诱发胚胎脑组织氧化性损伤的拮抗作用

目的　研究褪黑素 (MT)对苯妥英 (Phe)诱发的胚胎脑组织氧化性损伤有无保护作用。方法　妊娠Wistar母鼠于妊娠 (GD11～ 14 )ig 0和 10 0mg·kg- 1Phe ,4 0mg·kg- 1MT及 4 0mg·kg- 1MT +10 0mg·kg- 1Phe ;GD15脱颈椎处死动物 ,测定胎鼠脑组织各种与氧化性损伤有关的指标。结果　妊娠期染毒Phe导致胚胎脑组织H2 O2 水平升高 ,脂质过氧化和蛋白质氧化产物增加 ,超氧化物岐化酶、过氧化氢酶和谷胱甘肽过氧化物酶活性下降 ,总还原型谷胱甘肽(GSH)含量及总抗氧化力降低。妊娠期MT处理减少正常胎鼠脑中H2 O2 及产率 ;同时MT和Phe共同处理可阻断Phe诱发的氧化性损伤 ,GSH耗竭和抗氧化酶活性的下降。结论　MT对Phe诱发的胎鼠脑组织氧化性损伤有一定的拮抗作用。     

Phenols of virgin olive oil protects nuclear DNA against oxidative damage in HeLa cells

Oxidative DNA damage is an inescapable consequence for cells constantly exposed to oxidative stress derived from normal metabolic processes and from environmental factors. Phenolic compounds, which have strong antioxidant activity, prevent DNA damage by protecting the cells against harmful effects of oxidative stress. In this study, the effect of virgin olive oil phenolic extract (OOPE) was investigated on H₂O₂-induced mitochondrial DNA (mtDNA) and nuclear DNA (nDNA) damage in HeLa cells. DNA damage was assessed in mitochondria and two nuclear regions by using quantitative PCR (QPCR) assay. The cells were pre-treated with non-cytotoxic doses of OOPE for 4 h, and DNA damage was determined. OOPE alone does not change the steady-state level of DNA damage. The oxidative stress generated with 750 μM H₂O₂ caused two times greater damages in mtDNA compared to nDNA, which included the nonexpressed β-globin region (1.507 ± 0.110 lesions/10 kb) and the expressed APEX1 gene (1.623 ± 0.243 lesions/10 kb) with respect to the control region. When cells were preincubated with OOPE for 4 h, nDNA damage under stress condition was completely inhibited; however, mtDNA damage was not affected by this procedure. These results suggest that OOPE has a protective effect against nDNA damage in HeLa cells.     

Biomarkers of oxidative stress and DNA damage in agricultural workers: a pilot study

Oxidative stress and DNA damage have been proposed as mechanisms linking pesticide exposure to health effects such as cancer and neurological diseases. A study of pesticide applicators and farmworkers was conducted to examine the relationship between organophosphate pesticide exposure and biomarkers of oxidative stress and DNA damage. Urine samples were analyzed for OP metabolites and 8-hydroxy-2'-deoxyguanosine (8-OH-dG). Lymphocytes were analyzed for oxidative DNA repair activity and DNA damage (Comet assay), and serum was analyzed for lipid peroxides (i.e., malondialdehyde, MDA). Cellular damage in agricultural workers was validated using lymphocyte cell cultures. Urinary OP metabolites were significantly higher in farmworkers and applicators (p<0.001) when compared to controls. 8-OH-dG levels were 8.5 times and 2.3 times higher in farmworkers or applicators (respectively) than in controls. Serum MDA levels were 4.9 times and 24 times higher in farmworkers or applicators (respectively) than in controls. DNA damage (Comet assay) and oxidative DNA repair were significantly greater in lymphocytes from applicators and farmworkers when compared with controls. Markers of oxidative stress (i.e., increased reactive oxygen species and reduced glutathione levels) and DNA damage were also observed in lymphocyte cell cultures treated with an OP. The findings from these in vivo and in vitro studies indicate that organophosphate pesticides induce oxidative stress and DNA damage in agricultural workers. These biomarkers may be useful for increasing our understanding of the link between pesticides and a number of health effects.     

氯化镍在体内诱导大鼠DNA-蛋白质交联

目的　了解NiCl2 在体内对大鼠细胞的DNA产生何种损伤以及与聚腺苷二磷酸核糖聚合酶(PARP)活性的关系。方法　以 10 ,2 0 ,30mg·kg- 1NiCl2 ip给大鼠进行染毒 ,2 4h后处死动物 ,分离外周血淋巴细胞和肺细胞 ,应用单细胞凝胶电泳 (彗星试验 ) ,检测DNA单链、双链断裂和DNA 蛋白质交联 ,同时用 [3H]NAD渗透法检测PARP活性的变化。结果　外周血淋巴细胞和肺细胞均没有出现明显的DNA单链和双链断裂。所有剂量组的外周血淋巴细胞都出现了不同程度的DNA 蛋白质交联 ,交联率为 14 %～ 36 %,但没有剂量反应关系。 2 0mg·kg- 1NiCl2 也能诱导肺细胞DNA 蛋白质交联 ,交联率达 30 %。所有剂量组的NiCl2 均能明显抑制大鼠外周血淋巴细胞PARP酶的活性 ,酶活性下降至对照组的 38%～ 5 7%,但没有表现出剂量反应关系。大鼠肺细胞中该酶活性不受NiCl2 染毒的影响。结论　NiCl2 在体内环境下能诱导大鼠外周血淋巴细胞和肺细胞的DNA损伤 ,主要是引起DNA 蛋白质交联 ,而不直接造成DNA链的断裂 ;NiCl2 还能明显抑制外周血淋巴细胞的PARP酶活性 ,进而可能影响DNA修复。     

Repair of oxidative DNA damage in vitro: a tool for screening antioxidative compounds.

Reactive oxygen species (ROS) provoke the formation of base DNA alterations that are processed by an excision step of the lesion followed by a repair synthesis and ligation step to restore the strand continuity. We have reported previously the detection of DNA adducts by an in vitro chemiluminescence DNA repair synthesis assay (Salles et al., 1995) which allows the measurement of repair synthesis by cell-free extracts in damaged plasmid DNA adsorbed on sensitized microplate wells. The 3D (DNA damage detection) assay was performed in the presence of biotin-dUTP which was incorporated during the repair synthesis step. The extent of repair synthesis was measured in an ELISA reaction with ExtrAvidin-horse radish peroxidase and chemiluminescence detection. The 3D assay allows detection of any type of base alterations including base oxidation. Interestingly, under controlled production of ROS a screening procedure of antioxidants might be carried out with the 3D assay. By taking advantage of plasmid DNA adsorption, oxidative base damage can be recognized by the Escherichia coli Fpg protein which was detected in an ELISA reaction with specific antibody and chemiluminescence measurement (4D assay). With the sceening procedure of antioxidative compounds in mind, the development of such assays and their drawbacks are discussed.     

Protection by Salvia extracts against oxidative and alkylation damage to DNA in human HCT15 and CO115 cells

DNA damage induced by oxidative and alkylating agents contributes to carcinogenesis, leading to possible mutations if replication proceeds without proper repair. However, some alkylating agents are used in cancer therapy due to their ability to induce DNA damage and subsequently apoptosis of tumor cells. In this study, the genotoxic effects of oxidative hydrogen peroxide (H?O?) and alkylating agents N-methyl-N-nitrosourea (MNU) and 1,3-bis-(2-chloroethyl)-1-nitosourea (BCNU) agents were examined in two colon cell lines (HCT15 and CO115). DNA damage was assessed by the comet assay with and without lesion-specific repair enzymes. Genotoxic agents were used for induction of DNA damage in both cell lines. Protective effects of extracts of three Salvia species, Salvia officinalis (SO), Salvia fruticosa (SF), and Salvia lavandulifolia (SL), against DNA damage induced by oxidative and alkylating agents were also determined. SO and SF protected against oxidative DNA damage in HCT15 cells. SO and SL decreased DNA damage induced by MNU in CO115 cells. In addition to chemopreventive effects of sage plant extracts, it was also important to know whether these plant extracts may interfere with alkylating agents such as BCNU used in cancer therapy, decreasing their efficacy. Our results showed that sage extracts tested and rosmarinic acid (RA), the main constituent, protected CO115 cells from DNA damage induced by BCNU. In HCT15 cells, only SF induced a reduction in BCNU-induced DNA damage. Sage water extracts and RA did not markedly change DNA repair protein expression in either cell line. Data showed that sage tea protected colon cells against oxidative and alkylating DNA damage and may also interfere with efficacy of alkylating agents used in cancer therapy.     

Reactive oxygen species and oxidative DNA damage

Reactive oxygen species (ROS) such as the superoxide anion radical (O2.-) hydrogen peroxide (H2O2) and hydroxyl radical (.OH) have been implicated in the pathophysiology of various states, including ischemia reperfusion injury, haemorrhagic shock, atherosclerosis, heart failure, acute hypertension and cancer. The free radicals, nitric oxide (NO) and O2.- react to form peroxynitrite (ONOO-), a potent cytotoxic oxidant. A potential mechanism of oxidative damage is the nitration of tyrosine residues of protein, peroxidation of lipids, degradation of DNA and oligonucleosomal fragments. Several mechanisms are responsible for the protection of the cells from potential cytotoxic damage caused by free radicals. Cells have developed various enzymatic and nonenzymatic defense systems to control excited oxygen species, however, a certain fraction escapes the cellular defense and may cause permanent or transient damage to nucleic acids within the cells, leading to such events as DNA strand breakage and disruption of Ca2+ metabolism. There is currently great interest in the possible role of ROS in causing DNA damage that leads to cancer and spontaneous mutations. A high rate of oxidative damage to mammalian DNA has been demonstrated by measuring oxidized DNA bases excreted in urine after DNA repair. The rate of oxidative DNA damage is directly related to the metabolic rate and inversely related to life span of the organism.     

丹酚酸A对大鼠脑突触体和线粒体氧应激损伤的体外保护作用

利用蔗糖梯度法分离大鼠脑突触体和线粒体，以Fe^2＋-半胱氨酸（Cys）为氧自由基生成系统造成大鼠脑突触体和线粒体氧应激损伤模型. 在体外Fe^2＋-Cys与脑突触体和线粒体共同温孵可使丙二醛(MDA)生成量显著增加，线粒体ATP酶活性下降. 预先加入丹酚酸 A(Sal A)可显著抑制MDA生成，恢复线粒体 ATP酶活性，防止线粒体肿胀和膜流动性的降低. 通过电镜照片可看到Fe^2＋-Cys引起的线粒体和突触体结构病理性改变，预先加入Sal A可减轻Fe^2＋-Cys造成的这一损伤. 此外，Sal A可阻抑H₂O₂引起的脑突触体GSH含量的降低. 由此可见，Sal A体外对氧应激引起的大鼠脑突触体和线粒体脂质过氧化损伤有明显的保护作用.     

Evaluation of oxidative damage and inhibition of DNA repair in an in vitro study of nickel exposure

It has been suggested that Nickel is involved in oxidative damage and inhibition of DNA repair. We studied the effects of NiSO₄ on oxidative stress and DNA repair in Jurkat cells to elucidate its mechanism of action. Cells were treated with H₂O₂ and ROS generation (by flow cytometry), and oxidative DNA damage (as tail moment by Fpg-enzyme comet test), were evaluated immediately and after 4 and 24 h of DNA damage recovery occurred in presence or absence of NiSO₄ (0.017 and 0.17 μ ) to clarify possible interactions of Ni with DNA repair processes. Moreover, cells were exposed to the same doses of NiSO₄ for 4 and 24 hours to evaluate its direct oxidative effect. The results of the comet test showed high tail moment immediately after oxidative burst with a decreasing after 4 h of DNA recovery, and a slight increase after 24 h of recovery. The decreases were more limited for cells treated with NiSO₄ 0.17 μ indicating an inhibition of oxidative DNA damage repair by this substance. An induction of ROS was observed after 4 h of incubation with higher dose of NiSO₄. Cells treated with H₂O₂ showed the highest level of ROS after 4 h of recovery in presence of NiSO₄ 0.17 μ that remained at elevated levels also after 24 h of recovery suggesting a synergistic action of Ni with H₂O₂ in the reduction of cellular anti-oxidative defence activities.     

硫丹对成年大鼠生精功能的影响和氧化损伤

目的　研究硫丹对大鼠生精功能的影响是否与氧化损伤有关。方法　成年雄性SPFWistar大鼠随机分为 6组 ,每组 6只。 1～ 4组ig硫丹 0 ,2 .5 ,5 .0 ,7.5mg·kg- 1,每天 1次 ,每周 6次 ,持续 10周。5～ 6组在给硫丹 7.5mg·kg- 1的同时 ,ip维生素C(VitC) 2 0 ,4 0mg·kg- 1。给药结束时检查各组动物的每日精子生成量 (DSP)、附睾精子数和形态 ,并检测血清和睾丸、肝组织中的过氧化脂质 (LPO)和 8 羟基脱氧鸟苷 (8 OHdG)的含量。结果　给硫丹的5 .0和 7.5mg·kg- 1组出现短暂的中枢神经系统中毒症状。给药结束时 3个单给硫丹组DSP和附睾精子计数都低于对照组 ,精子畸形率则高于对照组。同时ipVitC两组的DSP和精子计数虽然仍低于对照组 ,但都比单给硫丹组有所改善。给硫丹组血清、肝脏和睾丸组织中的LPO和 8 OHdG都高于对照组。同时注射VitC组血清和上述组织中的LPO和8 OHdG都比单给硫丹 7.5mg·kg- 1组低。结论　大鼠长期大剂量接触硫丹能引起精子生成减少 ,异常精子比例增多 ,并能引起肝脏和睾丸组织脂质过氧化和DNA氧化损伤 ,而这些改变都能被抗氧化剂VitC部分改善 ,提示氧化损伤可能是硫丹生殖毒性的作用机理之一。