麦芽醇对小鼠的毒性作用及对红细胞抗氧化酶类活性的影响

作者过去的实验结果认为麦芽醇是一个有效的抗氧化剂,可以防止红细胞自身氧化及外源氧化剂的氧化作用。本文用小鼠按50mg/kg体重喂麦芽醇,每日一次,一个月后处死,观察各脏器的变化及红细胞内抗氧化酶(超氧化物歧化酶、过氧化氢酶)活性及谷胱甘肽含量。光镜观察各脏器无改变,抗氧化酶活性增强,谷胱甘肽含量增高。另外,麦芽醇服后,小鼠游泳耐力增强。     

山莨菪碱在体外清除超氧阴离子自由基保护大鼠红细胞膜蛋白巯基

<正> 山莨菪碱(anisodamine,Ani)为M胆碱受体阻断剂,对感染中毒性休克等有显著疗效。近年来的研究表明,该药具有抗氧化作用,为进一步了解其抗氧化机理,本文采用化学发光法探讨了Ani对超氧阴离子自由基O_2~-的体外清除作用,并观察了Ani对外源性H_2O_2损伤大鼠红细胞膜蛋白巯基的保护作用。     

Calpain抑制剂ALLN对H2O2诱导的661W细胞损害的影响

目的探讨ALLN(N-acetyl-leu-leu-norleucinal)在过氧化氢(H_2O_2)对661W光感受器细胞的毒性损害过程中的可能影响。方法 MTT法测定H_2O_2对661W细胞活性的影响;Western blot法检测在H_2O_2作用661W光感受器细胞中不同时间点Calpain 1和Calpain 2的蛋白水平。结果 MTT结果表明,H_2O_2作用于661W细胞24 h后,661W细胞数明显下降;100μmol·L^-1的H_2O_2作用于661W细胞12、18、24 h,Calpain 1和Calpain 2的蛋白水平随H_2O_2作用时间的延长而增加;MTT法测定661W细胞活性,发现ALLN+H_2O_2组细胞活性明显比单纯H_2O_2组高;MTT法检测不同浓度ALLN组(25、50、100、200μmol·L^-1)的细胞活性,结果显示ALLN组细胞活力与空白对照组无明显差别。结论Calpain抑制剂ALLN可减轻H_2O_2对661W细胞的毒性损害作用,为光感受器细胞氧化损伤及保护提供了实验依据。     

青藤碱对H_2O_2诱导人肝细胞损伤的保护作用研究

目的研究青藤碱对H_2O_2诱导人肝细胞(HLO_2)损伤的保护作用。方法以H_2O_2损伤HL0_2细胞建立氧化应激模型,MTT法检测细胞存活率;Annexin V-FITC/PI双染法检测细胞凋亡率。结果青藤碱能明显改善H_2O_2诱导的细胞损伤,与模型组相比,青藤碱可提高细胞存活率,降低细胞的凋亡率。结论青藤碱对H_2O_2所致的HL0_2细胞损伤具有明显的保护作用。     

虾青素对过氧化氢所致质膜氧化损伤的保护作用

目的探讨虾青素对H_2O_2所致质膜氧化损伤的保护作用。方法采用H_2O_2导致红细胞膜氧化损伤,以细胞形态学、细胞溶血率、丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性、膜封闭能力及流动性为指标,观察一定浓度的虾青素(1.0×10~(-7)、1.0×10~(-6)、1.0×10~(-5)mol·L~(-1))对H_2O_2所致质膜氧化损伤的保护作用。结果H_2O_2能导致红细胞溶血率和MDA含量增加、SOD活性、膜封闭能力及膜流动性下降。而经过一定浓度的虾青素预处理后,红细胞溶血率和MDA含量明显降低、SOD活性、膜封闭能力及膜流动性显著增强。结论虾青素对H_2O_2引起的质膜氧化损伤具有明显的保护作用,其机制可能与其抗氧化作用有关。     

落葵多糖体外抗氧化活性

目的探讨落葵多糖体外抗氧化活性作用。方法采用AP-TEMED体系和邻二氮菲-Fe~(2+)比色法测定落葵多糖对超氧阴离子自由基(O_2~-·)和羟自由基(·OH)的清除能力;采用比色法和TBA法测定落葵多糖生物活性对过氧化氢(H_2O_2)诱导红细胞溶血的抑制效应以及对小鼠肝组织自发性氧化的影响。结果落葵多糖具有显著清除O_2~-·和·OH作用,能抑制H_2O_2诱导的小鼠红细胞溶血,减少小鼠肝脏脂质过氧化产物丙二醛的产生(均P<0.01)。结论落葵多糖具有较强的抗氧化活性。     

仙人掌多糖组分对大鼠脑片氧化应激损伤的保护作用

目的研究仙人掌多糖对H_2O_2所致大鼠大脑皮质和海马脑片氧化应激损伤是否有保护作用。方法大鼠离体皮质和海马脑片与2mmol·L-1H_2O_2共孵育30min造成脑片的氧化应激损伤,分别于加入H_2O_2前加入仙人掌多糖作用30min,与H2O2同时加入仙人掌多糖作用30min或在H2O2损伤之后加入仙人掌多糖作用2h。TTC染色法检测脑片活性,并检测脑片培养液中乳酸脱氢酶(LDH)、超氧化物歧化酶(SOD)活性,谷胱甘肽(GSH)含量和总抗氧化能力(T-AOC)。结果H2O2孵育30min明显损伤大鼠海马和皮质脑片,TTC染色A490nm值下降,LDH释放增加,GSH含量和总抗氧化能力降低。加入H_2O_2前预先加入仙人掌多糖0.333和1.67mg·L-1作用30min显著抑制上述H2O2所致脑片损伤,使受损脑片孵育液中GSH含量增加,SOD活性和总抗氧化能力升高。结论仙人掌多糖能够减轻H2O2所致大鼠大脑皮质和海马脑片的氧化应激损伤,其机制可能与其增强机体的抗氧化能力有关。     

Hedgehog通路对心肌梗死及心肌细胞缺血缺氧的作用机制研究

目的探讨Sonic Hedgehog信号通路在正常心脏和缺血缺氧的心肌细胞的激活与表达。方法用左前降支结扎法构建心肌梗死模型,并用超声心动图鉴定。采用Western blot和免疫荧光染色分别检测12例心肌梗死组织,9例正常心肌组织,H_9C_2及H_2O_2诱导下的H_9C_2细胞的Shh、Ptch-1、Smo、Gli-1的表达。注射激动剂及抑制剂于H_2O_2诱导的缺血缺氧H_9C_2的细胞模型,再次检测Shh、Ptch-1、Smo、Gli-1的表达及强弱。结果 Shh、Gli-1在心肌梗死心脏表达,Ptch-1、Smo在正常心脏及心肌梗死心脏均表达,缺血缺氧H_9C_2细胞模型的Shh、Gli-1表达增加。H_2O_2诱导下的H_9C_2表达Gli-1、Shh,Ptch-1、Smo在正常H_9C_2和H_2O_2诱导下的H_9C_2均有表达。结论 Shh信号通路在缺血与氧化应激条件下被激活,并且具有促进心肌细胞的损伤修复作用。     

虾青素对过氧化氢所致HepG2细胞线粒体氧化损伤及生存能力下降的保护作用

目的探讨虾青素对H_2O_2导致的HepG2细胞线粒体氧化损伤及生存能力下降的保护作用。方法采用H_2O_2损伤HepG2细胞,测定细胞内Ca~(2+)浓度及线粒体膜电位、胞浆中细胞色素c(Cyt-c)的阳性表达率变化考察了虾青素对活性氧所致线粒体氧化损伤的保护作用;测定细胞存活率、乳酸脱氢酶(LDH)释放率考察了虾青素对活性氧所致细胞生存能力下降的保护作用。结果虾青素(1.0×10~(-7)、1.0×10~(-6)、1.0×10~(-5)mol·L~(-1))能明显抑制H_2O_2导致的细胞内Ca~(2+)浓度升高、线粒体膜电位降低、Cyt-c的释放增加;以及细胞存活率下降、LDH释放率增加。结论虾青素对H_2O_2所致细胞线粒体氧化损伤及细胞生存能力下降具有明显的保护作用,其机制可能与其抗氧化作用有关。     

p38和p42/p44 Ca~(2 )-钙调蛋白依赖性蛋白激酶信号在过氧化氢诱导牛主动脉内皮细胞凋亡中的作用

目的:研究p38和p42/p44 Ca~(2 ).钙调蛋白依赖性蛋白激酶(CCDPK)信号通路对过氧化氢(H_2O_2)诱导牛主动脉内皮细胞(BAEC)凋亡的调节作用.方法:H_2O_2处理BAEC 24 h后,荧光显微镜下观察形态学变化及凋亡细胞计数.MTT法测定细胞活性,琼脂糖凝胶电泳分析DNA降解,蛋白质印迹法检测磷酸化p38和p42/p44 CCDPK表达.结果:H_2O_2诱导BAEC产生典型的凋亡细胞形态学变化(核浓染,核碎裂)和DNA断片.H_2O_2(100-500μmol·L~(-1))浓度依赖性刺激磷酸化p42/p44和p38 CCDPK的表达.p42/p44 CCDPK抑制剂U0126显著增强H_2O_2致凋亡作用;然而p38 CCDPK抑制剂SB203580可增强H_2O_2诱导的磷酸化p42/p44 CCDPK的表达,但不影响BAEC的存活.结论:p42/p44 CCDPK对H_2O_2诱导的BAEC凋亡起保护作用,而p38 CCDPK不是介导H_2O_2所致细胞凋亡的主要信号通路.     

Maltol,an antioxidant component of Korean red ginseng,shows little prooxidant activity

Some antioxidant phenolic compounds exhibit prooxidant activity mainly due to their abilities to reduce Fe¹⁺ to Fe²⁺. Reducing ability and prooxidant activity of maltol, an antioxidant component of Korean red ginseng, were compared with those of pyrogallol. Maltol at 2 mM did not appreciably reduce Fe¹⁺ to Fe²⁺ and also failed to reduce nitroblue tetrazolium. Stimulation of hydroxyl radical mediated-deoxyribose degradation by pyrogallol was maximal at 60 μM. Maltol stimulated the deoxyribose degradation to a much less extent, and a similar stimulatory effect was observed at a concentration of more than 100-fold higher than that of pyrogallol. The stimulatory effect of maltol reached a plateau over 1 mM, suggesting the removal of hydroxyl radicals by excess maltol. In bleomycin-Fe³⁺-DNA assay, maltol at 2 mM produced a 2.5-fold increase of the iron-bleomycin-dependent DNA degradation over the basal value, whereas pyrogallol at 10 μM accelerated DNA degradation by ca. 10-fold. Furthermore, maltol inhibited Fe²⁺-stimulated DNA degradation by bleomycin. These results strongly suggested that maltol is an antioxidant with little prooxidant activity.     

麦芽醇对红细胞自氧化损伤的护保作用

红细胞在温育过程中发生自氧化损伤:氧合血红蛋白减少,高铁血红蛋白增多,超氧阴离子自由基增加,脂褐质升高,膜收缩蛋白及带3蛋白减少,带4.5及血红蛋白增多,汉氏小体含量升高,红细胞破溶。麦芽醇系红参中水溶性小分子有效成分,有抗氧化损伤,保护红细胞的作用。     

Role of maltol in advanced glycation end products and free radicals: in-vitro and in-vivo studies

Inhibitors of advanced glycation end products (AGEs) have potential as preventive agents against diabetic complications. In-vitro AGE inhibitory activity, transition metal chelating, and free radical scavenging activity tests have been used to screen for and identify effective AGE inhibitors. In an ongoing project to elucidate AGE inhibiting active components of heat-processed ginseng, maltol was selected for more detailed investigation. Although there are several lines of evidence concerning the antioxidant activity of maltol, the in-vitro and in-vivo inhibitory effects of maltol on AGE generation have not been evaluated. In the present study, the in-vitro AGE inhibitory effects and free radical scavenging activity of maltol were investigated. In addition, the in-vivo therapeutic potential of maltol against diabetic renal damage was tested using streptozotocin (STZ)-diabetic rats. Maltol showed a stronger AGE inhibitory effect than aminoguanidine, a well known AGE inhibitor. In addition, the hydroxyl radical scavenging activity of maltol on electron spin resonance (ESR) spectrometry was slightly stronger than that of aminoguanidine. Therefore, maltol was found to have stronger in-vitro AGE inhibiting activity compared with aminoguanidine. The administration of 50 mgkg(-1) per day of maltol suppressed the elevated serum levels of glycosylated protein, renal fluorescent AGEs, carboxymethyllysine, receptors for AGEs, and nuclear factor-kappaB p65 in diabetic control rats. These beneficial effects of maltol against STZ-diabetic renal damage were thought to result from its free radical scavenging and AGE inhibitory effects.     

Maltol/iron-mediated apoptosis in HL60 cells: participation of reactive oxygen species

Apoptosis of HL60 cells by maltol was analyzed in relation to the maltol/iron-mediated generation of reactive oxygen species. Addition of maltol with FeSO(4) induced an apoptotic cell death as judged by flow cytometry analysis and DNA fragmentation on electrophoresis, but maltol or iron alone did not affect the cells. Treatment of HL60 cells with maltol/iron complex caused an effective inactivation of aconitase the most sensitive enzyme to reactive oxygen species. Maltol/iron-mediated apoptosis and the inactivation of aconitase was prevented by TEMPOL, the scavenger of reactive oxygen species. These findings suggest that maltol/iron complex can generate reactive oxygen species by the redox cycling, resulting in an apoptosis of HL60 cells. Cytotoxicity of maltol can be explained by the prooxidant properties of this compound.     

Lipid peroxidation effects of a novel iron compound, ferric maltol. A comparison with ferrous sulphate

Lipid peroxidation effects of ferric maltol have been compared with those of ferrous sulphate both in lecithin liposomes and in brush border and mitochondrial membranes prepared from rat small intestine. Ferrous sulphate, but not ferric maltol, initiated peroxidation in liposomes as measured by conjugated diene production, but, with 500 microM ascorbic acid present, both caused intense peroxidation which was inhibitable by N2, tocopherol, maltol and ferrous chelators, but not by OH or H2O2 scavengers. The rate of peroxidation increased with ferrous sulphate concentration up to 100 microM but was independent of ferric maltol concentration between 5-500 microM. Material eluted from rat small intestine contained a reducing factor, similar in size to ascorbic acid, capable of generating ferrous ions from ferric maltol and initiating peroxidation. Peroxidation in mitochondrial membranes appeared unaffected by addition of iron whilst that in brush border membranes was detectable only in the presence of iron. At iron concentrations of 100 microM and above ferric maltol produced less liposomal peroxidation than ferrous sulphate. Maltol itself may delay recycling of Fe3+ to Fe2+. Thus ferric maltol could provide a less toxic alternative to ferrous salts in the oral treatment of iron-deficiency.     

Studies on eye irritation caused by chemicals in rabbits--II. An in vitro testing method using rat red blood cells for the prediction of eye irritation potential of chemicals

Rat red blood cells were used as an in vitro method to evaluate the eye irritation potential of chemicals in rabbits. The results using 116 chemicals of various categories including medicines, pesticides, detergents and solvents were analyzed for the prediction of possibility of eye irritation potentials. Eye irritation of chemicals was examined according to Draize method and chemicals were classified into three categories, (1) non or mild irritants, (2) moderate or severe irritants and (3) strong or corrosive irritants, based on the recovery of damages. The in vitro method consisted of two methods detecting the effects of chemicals mainly on protein and lipid in the membrane, which were evaluated by the induction of methemoglobin and hemolysis, respectively. Non- or mild irritants induced neither methemoglobin formation nor hemolysis. Most of moderate or severe irritants induced hemolysis, however, the potentials were low. Strong or corrosive irritants had high potentials for the induction of methemoglobin. The multivariate estimation by the above two in vitro data sets were 77.6% predictive of the in vivo classification.     

Role of free radical scavengers on phenylhydrazine induced hemolysis in rat

The mechanism of the phenylhydrazine induced oxidative hemolysis was studied on the point of role of the free radical scavengers in rats. Phenylhydrazine resulted in the degradation of hemoglobin and the lipid peroxidation of the erythrocyte membrane. Otherwise, the elevation of coenzyme Q9, endogenous CoQ in rats, levels in plasma was observed against the phenylhydrazine induced oxidative stress. Supplementation of coenzyme Q10, exogenous CoQ in rats, inhibited the phenylhydrazine induced hemolysis according to the suppression of both the degradation of hemoglobin and the lipid peroxidation of the erythrocyte membrane. These results suggest that free radical scavengers such as coenzyme Q9 and coenzyme Q10 have important roles on the phenylhydrazine induced hemolysis in rats.     

泰山四叶参多糖体外抗氧化活性的研究

目的观察泰山四叶参多糖(PCL)体外抗氧化作用。方法羟自由基(.OH)由Fenton反应体系产生,超氧阴离子(O2-)由邻苯三酚自氧化法产生,硫代巴比妥酸法测定肝匀浆丙二醛(MDA)相对含量反映PCL对脂质过氧化的影响,并观察PCL对H2O2诱导红细胞溶血的影响。结果PCL能显著清除.OH,抑制小鼠肝匀浆脂质过氧化反应,EC50和IC50分别为230.2和479.0μg/mL,并能清除O2-和抑制H2O2诱导的氧化性溶血,EC50和IC50分别为1 048.5和1 674.2μg/mL。结论PCL有较强的体外抗氧化作用,其活性与剂量呈正相关。     

Protective effect of Ugni molinae Turcz against oxidative damage of human erythrocytes.

Ugni molinae Turcz, also known as "Murtilla", is a plant that grows in the south of Chile. Infusions of its leaves have long been used in traditional native herbal medicine. The chemical composition of the leaves indicates the presence of polyphenols, which have antioxidant properties. In the present work, the antioxidant properties of U. molinae were evaluated in human erythrocytes exposed in vitro to oxidative stress induced by HClO. The experiments were carried out by scanning electron microscopy (SEM) and hemolysis measurements. The SEM observations showed that HClO induced a morphological alteration in the red blood cells from a discoid to an echinocytic form. According to the bilayer couple hypothesis, the formation of echinocytes indicates that HClO was inserted in the outer leaflet of the erythrocyte membrane. However, a concentration as low as 10 microM gallic acid equivalents (GAE) U. molinae aqueous extract neutralized the shape change effect of HClO applied in a concentration as high as 0.25 mM. The significant protection of U. molinae aqueous extract was also shown in the hemolysis experiments. In fact, very low concentrations of the extract considerably reduced the deleterious capacity of HClO to induce hemolysis in red blood cells. It is concluded that the location of the extract components into the membrane bilayer and the resulting restriction on its fluidity might hinder the diffusion of HClO and its consequent damaging effects. This conclusion can also imply that this restriction could apply to the diffusion of free radicals into cell membranes and the subsequent decrease of the kinetics of free radical reactions.