维生素C对镉负荷小鼠睾丸抗氧化功能的影响*

目的: 分析镉(Cd)负荷不同时间对小鼠睾丸抗氧化酶的影响及维生素C(VC)的保护作用。方法: 清洁级雄性昆明小鼠72只分为4组(n=18):对照组、Cd组(CdCl₂ 3 mg/kg)、VC组(200 mg/kg)、VC(200 mg/kg)+ Cd(CdCl₂ 3 mg/kg)组,每日染毒1次,染毒1 d和3 d及同时补充VC保护,第1日和第3日染毒24 h后,每组取半数小鼠称重,取血清和睾丸组织;检测睾丸脏器系数,血清和睾丸组织丙二醛(MDA)、超氧化物歧化酶(SOD),及睾丸组织谷胱甘肽过氧化物酶(GSH-Px)、还原型谷胱甘肽(GSH)、氧化型谷胱甘肽(GSSG)及总谷胱甘肽(T-GSH)。结果: 与对照组比较,Cd组1 d和3 d小鼠体重和睾丸脏器系数下降;染毒3 d,Cd组小鼠血清SOD显著降低、MDA显著升高(P＜0.05);Cd组1 d小鼠睾丸的SOD、GSH-Px、T-GSH及GSH/GSSG显著升高(P＜0.05),而3 d的上述指标均显著降低(P＜0.05),Cd组1 d和3 d MDA水平均显著升高(P＜0.05);VC处理后减轻的程度有所降低。与Cd组比较,VC+ Cd组血清SOD和MDA水平在染毒3 d变化有显著性差异(P＜0.05);VC+ Cd组在染毒1 d和3 d,小鼠睾丸的SOD、GSH-Px、T-GSH及GSH/GSSG水平变化有显著性差异(P＜0.05),VC+ Cd组在染毒3 d睾丸的MDA水平显著降低(P＜0.05)。与Cd组1 d比较,染毒3 d小鼠的血清SOD水平显著降低(P＜0.05),睾丸指标变化也有显著性差异(P＜0.05)。结论: VC处理可在一定程度上改善镉负荷小鼠的抗氧化功能,对睾丸氧化损伤具有保护作用。     

毛蕊花苷对递增负荷运动小鼠骨骼肌损伤的保护作用

本研究采用小鼠跑台训练模型,应用免疫共沉淀等方法,研究毛蕊花苷对递增负荷运动小鼠骨骼肌损伤的保护作用及对谷胱甘肽的影响。90只小鼠随机分为:正常对照组(A)、正常+毛蕊花苷组(B)、单纯运动组(C)、运动+毛蕊花苷低剂量组(D)、运动+毛蕊花苷中剂量组(E)、运动+毛蕊花苷高剂量组(F).结果表明:与C组比较,D、E、F组小鼠骨骼肌损伤程度依次减轻,F组小鼠骨骼肌形态基本正常。F组小鼠血浆CK水平、骨骼肌组织GSSG含量分别低于C、D、E组;但CK水平高于A、B组,均P0.01;GSSG含量与A、B组比较,差异无显著性,P0.05。F组小鼠骨骼肌组织GSH含量、GSH/GSSG比值、GCL和GR酶活性、RyR1复合物中GSH表达水平分别高于C、D、E组,但低于A、B组,均P0.01。研究结果提示毛蕊花苷能降低递增负荷运动小鼠血浆CK的活性,保护运动鼠骨骼肌的形态;其机理与其提高运动鼠骨骼肌组织GSH含量和GCL、GR酶的活性,降低GSSG/GSH比值;提高RyR1复合物中GSH表达水平有关。     

外源NO对NaCl胁迫下黄瓜（Cucumis sativus L.）幼苗生长和谷胱甘肽抗氧化酶系统的影响

采用营养液水培,研究了外源一氧化氮(NO)对黄瓜(Cucumis sativus L.)幼苗生长和叶片谷胱甘肽抗氧化酶系统的影响.结果表明,正常生长条件下添加NO能促进黄瓜幼苗生长,而添加NO信号传递途径关键酶鸟苷酸环化酶(cGC)抑制剂亚甲基蓝(MB-1)显著抑制了黄瓜幼苗的生长;添加NO显著缓解了盐胁迫对黄瓜幼苗生长的抑制,提高了叶片谷胱甘肽还原酶(GR)活性、脱氢抗坏血酸还原酶(DHAR)活性、抗坏血酸过氧化物酶(APX)及还原型谷胱甘肽(GSH)、抗坏血酸(ASA)含量,降低了氧化型谷胱甘肽(GSSG)含量,提高了GSH/GSSG,对单脱氢抗坏血酸还原酶(MDAR)活性无显著影响;NaCl胁迫下添加NO的同时添加MB-1抑制了GR活性的提高,GSH和ASA含量、GSH/GSSG均降低,GSSG含量提高,但对MDAR、APX和DHAR活性无显著影响,表明NaCl胁迫下NO对GR活性、GSH和ASA含量、GSH/GSSG的调节可能是通过cGC介导的,对MDAR无明显的调节作用,对DHAR、APX的调节还存在其它途径.     

摄入异烟肼对家蚕幼虫体内谷胱甘肽氧化还原循环和谷胱甘肽S-转移酶活性的影响

为了建立家蚕Bombyx mori的药物筛选和毒性评价模型, 以剂量为2 000 mg/kg的抗结核模药异烟肼饲喂家蚕5龄第3天幼虫后检测其中肠和脂肪体的抗氧化解毒相关代谢的变化。结果表明： 雌蚕中肠组织中, 总谷胱甘肽(GSH+2GSSG)、 还原型谷胱甘肽(reduced glutathione, GSH)和氧化型谷胱甘肽(oxidized glutathione, GSSG)含量均呈现迅速上升再缓慢下降趋势; 谷胱甘肽S 转移酶(glutathione S-transferase, GST)活性升高到较大值后逐渐降低; GSH/GSSG的比值下降表明, 在72 min后中肠组织向氧化态转移。脂肪体组织中, 总谷胱甘肽、 GSH和GSSG含量变化均呈现迅速下降再迅速上升的趋势; GST活性达到最大值后逐渐降低后趋于平稳; GSH/GSSG比值升高表明, 在72 min后脂肪体组织向还原态转移。无论雌蚕还是雄蚕, 总谷胱甘肽、 GSH和GSSG含量以及GST活性均是脂肪体高于中肠。雌蚕的总谷胱甘肽含量、 GSH和GSSG含量高于雄蚕, 但雄蚕的GST活性高于雌性。结果说明, 摄入异烟肼引起了家蚕幼虫体内谷胱甘肽氧化还原状态的改变和酶活性的变化, 在这个过程中脂肪体起主要解毒代谢作用。     

5-氨基乙酰丙酸(ALA)对盐胁迫下葡萄叶片中AsA-GSH循环的影响

以两个耐盐程度不同的葡萄品种‘夏黑’(耐盐性较弱)和‘里扎马特’(耐盐性较强)为材料,分析了不同浓度ALA对不同浓度盐胁迫下葡萄叶片中AsA-GSH循环的影响。研究表明:喷施75 mg·L-1 ALA可显著提高2 g·kg-1盐胁迫下‘夏黑’葡萄叶片中抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)、单脱氢抗坏血酸还原酶(MDHAR)、脱氢抗坏血酸还原酶(DHAR)的活性以及还原型抗坏血酸(As A)、还原型谷胱甘肽(GSH)含量和AsA/DHA、GSH/GSSG比值,显著降低氢抗坏血酸(DHA)与氧化型谷胱甘肽(GSSG)含量;而喷施150 mg·L-1 ALA可显著提高4 g·kg-1盐胁迫下‘里扎马特’葡萄叶片中APX、GR、MDHAR、DHAR的活性以及AsA、GSH含量和AsA/DHA、GSH/GSSG比值,显著降低DHA与GSSG含量。     

槲皮素调节大鼠肝细胞谷胱甘肽代谢的机制

目的：探讨60 μmol/L槲皮素调节BRL大鼠肝细胞谷胱甘肽（GSH）代谢的可能机制。方法：采用MTT法测定槲皮素对BRL细胞活力的影响;采用试剂盒法检测细胞内GSH和GSSG的含量,以及谷胱甘肽过氧化物酶（GSH-Px）、肝脏谷胱甘肽 S转移酶（GST）、γ-谷氨酰半胱氨酸连接酶（γ-GCL）、谷胱甘肽还原酶（GR）的活性;采用实时荧光定量PCR法检测GSH-Px、GST、γ-GCL和GR基因mRNA的表达情况;采用ELISA法测定细胞内的Keap1、总Nrf2、ERK1/2、磷酸化ERK1/2（p-ERK1/2）、JNK、p-JNK,以及细胞核Nrf2的蛋白水平。结果：槲皮素不影响大鼠肝细胞的活力（P>0.05）;与对照组比较,槲皮素组细胞内还原型GSH含量和GSH/GSSG比值（P<0.05）显著降低（P<0.05）,γ-GCL酶活性显著减弱（P<0.05）,GR和GSH-Px的mRNA表达显著减少（P<0.05）,Keap1和JNK蛋白水平显著降低（P<0.05）。结论：槲皮素可减少BRL大鼠肝细胞还原型GSH的含量,这种作用主要与槲皮素抑制GSH的生成有关。     

氧化应激条件下G6PD对Raji细胞内GSH水平的影响

目的：观察体外培养的Burkit淋巴瘤（Raji）细胞在氧化应激条件下细胞内葡萄糖-6-磷酸脱氢酶（G6PD）对还原型谷胱甘肽（GSH）水平的影响。方法：体外培养Raji细胞,分别在G6PD活性被抑制及不抑制的情况下,检测细胞在酚嗪甲酸硫酯（PMS）作用后60min及360min时G6PD、谷胱甘肽还原酶（GR）、谷胱甘肽过氧化物酶（GPx）活性及GSH水平。结果：在PMS作用下,Raji细胞内GSH水平在60min时显著下降（P〈0．01）而360min时可上升至对照组水平,G6PD及GPx活性持续显著升高（P〈0．01）而GR活性在360min时有显著升高（P〈0．01）;使用脱氢表雄酮（DHEA）抑制G6PD活性后,Raji细胞再在PMS作用下,细胞内各指标与PMS处理组比较,GSH水平显著降低（P〈0．01）,GPx活性在60min时显著增高（P〈0．05）而GR活性在360min时显著降低（P〈0．01）。结论：细胞在氧化应激条件下G6PD可能是Raji细胞内影响GSH水平的一个关键因子,对维持胞内GSH水平起重要的调节作用。     

外源NO对NaCl胁迫下黄瓜幼苗生长和根系谷胱甘肽抗氧化酶系统的影响

以津春2号黄瓜为材料,采用营养液水培的方法,研究了外源一氧化氮(NO)对黄瓜幼苗生长和根系谷胱甘肽抗氧化酶系统的影响.结果表明,(1)正常生长条件下添加NO能促进黄瓜幼苗生长,而添加亚甲基蓝(MB-1)显著抑制黄瓜幼苗的生长;(2)添加NO显著缓解了NaCl胁迫对黄瓜幼苗生长的抑制,提高根系还原型谷胱甘肽(GSH)含量、抗坏血酸过氧化物酶(APX)和谷胱甘肽还原酶(GR)活性,而氧化型谷胱甘肽(GSSG)含量略有下降,同时缓解了NaCl胁迫下抗坏血酸(ASA)含量的下降幅度;(3)NaCl胁迫下添加NO的同时添加MB-1可部分解除NO的作用,与NaCl胁迫下单独添加NO处理比较,GR活性、GSH和ASA含量均降低,GSSG含量提高,APX先升高后下降.研究发现,外源NO可能通过鸟苷酸环化酶(cGC)介导来调节NaCl胁迫下黄瓜幼苗根系GR活性和GSH、GSSG、ASA含量,提高抗氧化酶活性和非酶抗氧化物质含量,增强植株对活性氧的清除能力,减少膜脂过氧化,缓解NaCl胁迫对黄瓜幼苗造成的伤害.     

外源一氧化氮供体对NaCl胁迫下多裂骆驼蓬幼苗叶片ASA-GSH循环的影响

研究了外源一氧化氮(NO)供体硝普钠(SNP)对NaCl胁迫下多裂骆驼蓬幼苗抗坏血酸(ASA)-谷胱甘肽(GSH)循环抗氧化系统及H2O2和丙二醛(MDA)含量的影响。结果表明,0.15mmol.L-1SNP能提高300mmol.L-1NaCl胁迫下多裂骆驼蓬幼苗叶片抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)和谷胱甘肽转硫酶(GST)活性,增加还原型抗坏血酸(ASA)和谷胱甘肽(GSH)含量,降低脱氢抗坏血酸(DHA)和氧化型谷胱甘肽(GSSG)含量,提高ASA/DHA、GSH/GSSG比率,降低H2O2和MDA水平,对单脱氢抗坏血酸还原酶(MDAR)和脱氢抗坏血酸还原酶(DHAR)活性无显著影响。NO信号转导途径关键酶鸟苷酸环化酶(GC)抑制剂亚甲基蓝(MB)逆转了SNP对盐胁迫下APX、GR、GST活性和ASA、GSH、DHA,H2O2、MDA含量及ASA/DHA、GSH/GSSG比率的调节效应。由此表明,NO可能通过GC介导的cGMP信号转导参与ASA-GSH循环活性氧清除系统的调节,从而缓解盐胁迫诱导的氧化伤害。     

外源NO对铜胁迫下番茄幼苗根系抗坏血酸谷胱甘肽循环的影响

采用营养液培养方法,研究外源NO对铜胁迫下番茄(Lycopersicon esculentum Mill.)幼苗根系抗坏血酸(AsA)-谷胱甘肽(GSH)循环中抗氧化物质和抗氧化酶系的影响.结果表明：外施适量NO(硝普钠)可提高铜胁迫下番茄幼苗根系AsA、GSH含量和AsA/DHA(氧化型抗坏血酸)、GSH/GSSG(氧化型谷胱甘肽),降低DHA和GSSG含量.添加100 μmol·L^-1 BSO(谷胱甘肽合成酶抑制剂)处理下,外源NO可提高铜胁迫下番茄幼苗根系的AsA含量、AsA/DHA及抗坏血酸酶(AAO)、单脱氢抗坏血酸还原酶(MDHAR)和脱氢抗坏血酸还原酶(DHAR)比活性,降低DHA、GSH、GSSG含量及抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)比活性;添加250 μmol·L^-1 BSO处理下,外源NO提高了铜胁迫下番茄幼苗根系的AsA、GSH、GSSG含量、AsA/DHA及APX和GR比活性,降低了DHA含量及AAO、DHAR和MDHAR比活性.说明外源NO影响了铜胁迫下番茄根系的AsA-GSH代谢循环,并通过调节AsA/DHA、GSH/GSSG的变化来减轻氧化胁迫,从而缓解铜胁迫对番茄根系的伤害.     

外源脯氨酸对盐胁迫下甜瓜幼苗根系抗坏血酸-谷胱甘肽循环的影响

以2个不同耐盐强度的甜瓜品种‘玉皇’（耐盐性强）和‘雪美’（耐盐性弱）为材料,采用营养液栽培方法,研究外源脯氨酸对盐胁迫下甜瓜幼苗根系抗坏血酸-谷胱甘肽循环的影响。结果显示：（1）盐胁迫下,2个甜瓜品种根系内的还原型抗坏血酸（ASA）、还原型谷胱甘肽（GSH）含量降低,氧化型谷胱甘肽（GSSG）含量升高,且‘雪美’变化幅度大于‘玉皇’;（2）盐胁迫下,施用外源脯氨酸提高了2个甜瓜品种根系中ASA和GSH的含量,降低了GSSG含量,同时也提高了GSH/GSSG的比值,且对‘雪美’的作用大于‘玉皇’;（3）盐胁迫处理3 d时,2个甜瓜品种根系的抗坏血酸过氧化物酶（APX）、脱氢抗坏血酸还原酶（DHAR）、谷胱甘肽还原酶（GR）活性均下降,且‘雪美’下降的幅度较大;随着胁迫时间的延长（5 d时）,‘玉皇’幼苗根系内APX、DHAR、GR活性有所上升,‘雪美’根系中这3种酶活性则进一步降低;（4）盐胁迫下,施用外源脯氨酸提高了2个甜瓜品种根系内的APX、DHAR和GR的酶活性,且对‘雪美’的作用大于‘玉皇’。本研究结果表明,外源脯氨酸可以通过增加非酶促抗氧化物质ASA、GSH的含量和抗氧化酶活性,提高抗坏血酸-谷胱甘肽循环清除活性氧的能力,从而缓解盐胁迫对甜瓜植株的伤害。     

Parameters related to oxygen free radicals in erythrocytes,plasma and epidermis of the hairless rat

The following parameters related to oxygen free radicals (OFR) were determined in erythrocytes and the epidermis of hairless rats: catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), reduced (GSH) and oxidized (GSSG) glutathione, glutathione S-transferase (GST), superoxide dismutase (SOD) and thiobarbituric acid reactive substances (TBARS). GSH, GSSG and TBARS were also analyzed in plasma. In erythrocytes, the Pearson correlation coefficients (r) were significant (p < 0.001) between glutathione and other parameters as follows: GSH correlated negatively with GSSG (r = -0.665) and TBARS (r = -0.669); GSSG correlated positively with SOD (r = 0.709) and TBARS (r = 0.752). Plasma GSSG correlated negatively with erythrocytic thermostable GST activity (r = -0.608; p=0.001) and with erythrocytic total GST activity (r = -0.677; p < 0.001). In epidermis (p < 0.001 in all cases), GSH content correlated with GSSG (r = 0.682) and with GPx (r = 0.663); GSSG correlated with GPx (r = 0.731) and with GR (r = 0.794). By multiple linear regression analysis some predictor variables (R(2)) were found: in erythrocytes, thermostable GST was predicted by total GST activity and GSSG, GSSG content was predicted by GSH and by the GSH/GSSG ratio and GPx activity was predicted by GST, CAT and SOD activities; in epidermis, GSSG was predicted by GR and SOD activities and GR was predicted by GSSG, TBARS and GPx. It is concluded that the hairless rat is a good model for studying OFR-related parameters simultaneously in blood and skin, and that it may provide valuable information about other animals under oxidative stress.     

长期酒精摄入对雄性大鼠生殖系统的损伤

目的：研究长期酒精摄入对雄性大鼠生殖系统的损伤机制。方法：选用8周龄的SD大鼠,进行随机分组：对照组（5％蔗糖,口服）;酒精组（4g／kg,口服）。连续12周后,分别取附睾考察精子数目、活力;取血清检测睾酮和促黄体生产素（LH）含量;计算睾丸一体重比,并检测睾丸中丙二醛（MDA）、谷胱甘肽（GSH）含量以及谷胱甘肽过氧化物酶（GPx）和超氧化物歧化酶（SOD）的活性;同时检测凋亡相关蛋白bax,bcl-2以及caspase．3前体和剪切体的蛋白表达。结果：酒精组12周后,大鼠的睾丸．体重比明显降低（P〈0．05）,精子数目减少（P〈0．01）,精子活力下降（P〈0．01）;血清中睾酮含量下降（P〈0．05）,LH含量增加（P〈0．05）;睾丸中MDA含量增加（P〈0．01）,GSH含量降低（P〈0．05）,GPX和SOD活性下降（P〈0,01）;凋亡相关蛋白bax表达增加（P〈0．05）,caspase-3剪切体与前体的比值增加（P〈O．01）。结论：长期摄入酒精引起的大鼠睾丸内氧化应激水平的增加是其导致其生殖系统损伤的重要因素之一。     

硒酸精氨酸对小鼠酒精性肝损伤的保护作用

目的探讨硒酸精氨酸对小鼠酒精性肝损伤的保护作用。方法用连续灌服酒精的方法建立小鼠酒精性肝损伤模型。将60只雄性小鼠随机分为四组：对照组,模型组,硒酸精氨酸处理组和二氧化硒处理组。连续灌胃8周后,测定小鼠血清中天冬氨酸氨基转移酶（AST）,丙氨酸转移酶（ALT）,肝匀浆中超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GPx）、谷胱甘肽（GSH）的含量。对肝脏切片做HE染色和Masson染色,在光镜下观察肝脏病理学变化。结果硒酸精氨酸能显著降低酒精性肝损伤引起的AST的升高（P〈0．01）,有效保持了肝脏中GPx和SOD的活性（P〈0．01）。病理学观察结果与酶学变化相一致,硒酸精氨酸对肝脏的保护作用明显优于二氧化硒。结论硒酸精氨酸对小鼠酒精性肝损伤具有显著的保护作用,效果也优于二氧化硒。     

Control of the NADPH supply and GSH recycling for oxidative stress management in hepatoma and liver mitochondria

To unveil what controls mitochondrial ROS detoxification, the NADPH supply and GSH/GSSG recycling for oxidative stress management were analyzed in cancer and non-cancer mitochondria. Therefore, proteomic and kinetomic analyses were carried out of the mitochondrial (i) NADPH producing and (ii) GSH/GSSG recycling enzymes associated to oxidative stress management. The protein contents of the eight enzymes analyzed were similar or even higher in AS-30D rat hepatoma mitochondria (HepM) than in rat liver (RLM) and rat heart (RHM) mitochondria, suggesting that the NADPH/GSH/ROS pathway was fully functional in cancer mitochondria.The Vmax values of IDH-2 were much greater than those of GDH, TH and ME, suggesting that IDH-2 is the predominant NADPH producer in the three mitochondrial types; in fact, the GDH reverse reaction was favored. The Vmax values of GR and GPx were lower in HepM than in RLM, suggesting that the oxidative stress management is compromised in cancer mitochondria. The Km values of IDH-2, GR and GPx were all similar among the different mitochondrial types.Kinetic modeling revealed that the oxidative stress management was mainly controlled by GR, GPx and IDH. Modeling and experimentation also revealed that, due to their higher IDH-2 activity and lower GPx activity presumably by acetylation, HepM (i) showed higher steady-state NADPH levels; (ii) required greater peroxide concentrations to achieve reliable steady-state fluxes and metabolite concentration; and (iii) endured higher peroxide concentrations without collapsing their GSH/GSSG ratios. Then, to specifically prompt lower GSH/GSSG ratios under oxidative stress thus compromising cancer mitochondria functioning, GPx should be re-activated.     

In vitro interactions of thallium with components of the glutathione-dependent antioxidant defence system

We investigated the hypothesis that thallium (Tl) interactions with the glutathione-dependent antioxidant defence system could contribute to the oxidative stress associated with Tl toxicity. Working in vitro with reduced glutathione (GSH), glutathione reductase (GR) or glutathione peroxidase (GPx) in solution, we studied the effects of Tl⁺ and Tl³⁺ (1-25 μM) on: (a) the amount of free GSH, investigating whether the metal binds to GSH and/or oxidizes it; (b) the activity of the enzyme GR, that catalyzes GSH regeneration; and (c) the enzyme GPx, that reduces hydroperoxide at expense of GSH oxidation. We found that, while Tl⁺ had no effect on GSH concentration, Tl³⁺ oxidized it. Both cations inhibited the reduction of GSSG by GR and the diaphorase activity of this enzyme. In addition, Tl³⁺per se oxidized NADPH, the cofactor of GR. The effects of Tl on GPx activity depended on the metal charge: Tl⁺ inhibited GPx when cumene hydroperoxide (CuOOH) was the substrate, while Tl³⁺-mediated GPx inhibition occurred with both substrates. The present results show that Tl interacts with all the components of GSH/GSSG antioxidant defence system. Alterations of this protective pathway could be partially responsible for the oxidative stress associated with Tl toxicity.     

Protective role of glutathione reductase in paraquat induced neurotoxicity

Paraquat (PQ), a widely used herbicide is a well-known free radical producing agent. The mechanistic pathways of PQ neurotoxicity were examined by assessing oxidative/nitrosative stress markers. Focus was on the role of glutathione (GSH) cycle and to examine whether the pre-treatment with enzyme glutathione reductase (GR) could protect the vulnerable brain regions (VBRs) against harmful oxidative effect of PQ. The study was conducted on Wistar rats, randomly divided in five groups: intact-control group, (n=8) and four experimental groups (n=24). All tested compounds were administered intrastriatally (i.s.) in one single dose. The following parameters of oxidative status were measured in the striatum, hippocampus and cortex, at 30min, 24h and 7days post treatment: superoxide anion radical (O(2)(-)), nitrate (NO(3)(-)), malondialdehyde (MDA), superoxide dismutase (SOD), total GSH (tGSH) and its oxidized, disulfide form (GSSG) and glutathione peroxidase (GPx). Results obtained from the intact and the sham operated groups were not statistically different, confirming that invasive i.s. route of administration would not influence the reliability of results. Also, similar pattern of changes were observed between ipsi- and contra- lateral side of examined VBRs, indicating rapid spatial spreading of oxidative stress. Mortality of the animals (10%), within 24h, along with symptoms of Parkinsonism, after awakening from anesthesia for 2-3h, were observed in the PQ group, only. Increased levels of O(2)(-), NO(3)(-) and MDA, increased ratio of GSSG/GSH and considerably high activity of GPx were measured at 30min after the treatment. Cytotoxic effect of PQ was documented by drastic drop of all measured parameters and extremely high peak of the ratio GSSG/GSH at 24th hrs after the PQ i.s. injection. In the GR+PQ group, markedly low activity of GPx and low content of NO(3)(-) (in striatum and cortex) were measured during whole experiment, while increase value was observed only for O(2)(-), at 7th days. We concluded that oxidative/nitrosative stress and excitotoxicity are the most important events since the early stage of PQ induced neurotoxicity. Based on the ratio GSSG/GSH, the oxidation of GSH to GSSG is probably dominant way of GHS depletion and main reason for reduced antioxidative defense against PQ harmful oxidative effect. The GR pre-treatment resulted in the absence of Parkinson's disease-like symptoms and mortality of the rats. Additionally, oxidative/nitrosative stress did not developed, as well as almost diminished metabolism of the VBRs at 24th hours (as has been documented in the PQ group) did not occurred in the GR+PQ, suggesting a neuroprotective role for the GR in PQ induced neurotoxicity.     

In vitro Interactions of Thallium with Components of the Glutathione-dependent Antioxidant Defence System

We investigated the hypothesis that thallium (Tl) interactions with the glutathione-dependent antioxidant defence system could contribute to the oxidative stress associated with Tl toxicity. Working in vitro with reduced glutathione (GSH), glutathione reductase (GR) or glutathione peroxidase (GPx) in solution, we studied the effects of Tl⁺ and Tl³⁺ (1-25 μM) on: (a) the amount of free GSH, investigating whether the metal binds to GSH and/or oxidizes it; (b) the activity of the enzyme GR, that catalyzes GSH regeneration; and (c) the enzyme GPx, that reduces hydroperoxide at expense of GSH oxidation. We found that, while Tl⁺ had no effect on GSH concentration, Tl³⁺ oxidized it. Both cations inhibited the reduction of GSSG by GR and the diaphorase activity of this enzyme. In addition, Tl³⁺per se oxidized NADPH, the cofactor of GR. The effects of Tl on GPx activity depended on the metal charge: Tl⁺ inhibited GPx when cumene hydroperoxide (CuOOH) was the substrate, while Tl³⁺-mediated GPx inhibition occurred with both substrates. The present results show that Tl interacts with all the components of GSH/GSSG antioxidant defence system. Alterations of this protective pathway could be partially responsible for the oxidative stress associated with Tl toxicity.     

牛角花齿蓟马为害对紫花苜蓿AsA、GSH含量及相关代谢酶活性的影响

为了明确非酶抗氧化物质抗坏血酸(AsA)、还原型谷胱甘肽(GSH)及相关代谢酶抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)在紫花苜蓿(Medicago sativa L.)对牛角花齿蓟马Odontothrips loti Haliday为害的抗性中的作用,测定了不同牛角花齿蓟马虫口密度下抗、感蓟马苜蓿无性系R-1、I-1的AsA、GSH含量及APX、GR活性的变化。结果表明:受牛角花齿蓟马为害后,R-1无性系在低虫口密度(1、3头/枝条)下,AsA、GSH含量和GR活性均上升,在高虫口密度(5、7头/枝条)下,AsA含量和GR活性先升高后下降,GSH含量上升后保持稳定;I-1无性系的AsA、GSH含量先升高后下降,GR活性在为害后期呈上升趋势;R-1、I-1无性系的APX活性均先上升后下降,但R-1无性系APX活性的上升速率及下降速率小于I-1无性系。说明AsA、GSH含量及APX、GR活性的升高可能是紫花苜蓿对牛角花齿蓟马诱导抗性的一种表现,但I-1无性系对蓟马为害的应激反应滞后于R-1无性系。在牛角花齿蓟马为害后期,R-1无性系体内的AsA、GSH含量及APX、GR活性仍处于较高水平,也说明了R-1无性系对牛角花齿蓟马为害的抗性较I-1无性系强。     

Antioxidant enzyme activities and the production of MDA and 8-oxo-dG in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is a neoplastic disease susceptible to antioxidant enzyme alterations and oxidative stress. We have examined the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), and the oxidized/reduced glutathione (GSSG/GSH) ratio together with the levels of malondialdehyde (MDA) and 8-oxo-2'-deoxyguanosine (8-oxo-dG) in lymphocytes of CLL patients and compared them with those of normal subjects of the same age. SOD and CAT activity decreased in CLL lymphocytes while GPx activity increased. GSH content of CLL lymphocytes also increased, and GSSG concentration remained constant. Thus, a reduced GSSG/GSH ratio was obtained. The oxidation product MDA, and the damaged DNA base 8-oxo-dG were also increased in CLL. The observed changes in enzyme activities, GSSG/GSH ratio, and MDA were significantly enhanced as the duration of the disease increased in years. The results support a predominant oxidative stress status in CLL lymphocytes and emphasize the role of the examined parameters as markers of the disease evolution.