颐脑解郁方对抑郁大鼠脑1H波谱的干预作用

该文主要研究抑郁大鼠脑的¹H MRS变化及颐脑解郁方的干预作用. 将雄性Wistar大鼠随机分为正常组、模型组、西药组和中药组,每组5只. 正常组常规饲养,模型组、中药组和西药组给予21 d的慢性不可预知的温和应激. 应激结束中药组予颐脑解郁方、西药组予盐酸氟西汀进行干预. 干预结束后,通过检测左侧海马及前额叶皮质N-乙酰天门冬氨酸（NAA）、胆碱（Cho）、肌酸（Cr）等代谢物水平,分别计算NAA、Cho与Cr的比值,进而对脑组织代谢进行定性及定量分析. 得到：1. 海马区域：与正常组相比,模型组、西药组大鼠海马NAA/Cr降低（P<0.01）,中药组大鼠NAA/Cr与模型组相比升高（P<0.05）;与正常组相比,模型组Cho/Cr升高（P<0.05）,中药组Cho/Cr比模型组显著低（P<0.01）. 2. 前皮质区域：与正常组相比,模型组、西药组大鼠前皮质NAA/Cr降低（P<0.01）,中药组大鼠NAA/Cr较模型组显著升高（P<0.01）;模型组、西药组Cho/Cr与正常组相比显著升高（P<0.01）;与模型组相比,中药组、西药组Cho/Cr降低（P<0.01,P<0.05）. 这些结果说明颐脑解郁方可改善大鼠海马和前皮质的物质代谢,推测其抗抑郁作用主要与调节脑组织异常代谢有关.     

维生素C对大鼠急性肺损伤时铁元素水平的干预作用

将ALI实验动物随机分为13组,其中6组为维生素C治疗组,ALI后均立即给予维生素C治疗,依照采集肺组织标本不同时间点分为：6h组、8h组、12h组、16h组和24h组（均12h追加一次维生素C）、36h组;用生理盐水替换维生素C为6组阳性对照组;阴性对照1组。用原子分光光度计检测肺组织铁含量。阴性对照组铁含量为25.1828μg·g-1;损伤期大鼠体内铁元素均比正常值低,治疗组和对照组组内均有明显差异（P〈0.05）;各时间点治疗组与阳性照相比均呈有意义改变（P〈0.01）;各时间点的治疗组、阳性对照组与阴性对照组相比均呈有意义改变（P〈0.05或P〈0.01）。ALI时铁含量降低;用VC后铁有一定程度升高,说明VC对ALI时铁的水平有一定调节作用。     

维生素C对紫外线诱发DNA损伤的保护作用

用拉曼光谱探讨维生素C对紫外线诱发DNA损伤的保护作用。测量了小牛胸腺DNA水溶液及其添加微量维生素C并经过9min和30min紫外辐射的拉曼光谱,紫外线的辐射照度为18．68W／m^2。实验结果表明：在浓度为O．2mmol／L的维生素C存在的条件下,全波段的紫外辐射对DNA只造成了轻微的损伤。DNA被保护可能是因为紫外辐射虽然产生了对DNA损伤很大的自由基,但维生素C具有清除自由基的能力。另外由于DNA和维生素C在260nm处对紫外线都有很强的吸收能力,因此也可能是维生素C对紫外线的吸收能力强于DNA,从而保护了DNA。     

稀土镧对雄性小鼠睾丸cAMP和自由基的影响

采用酶联免疫吸附法和分光光度法,通过腹腔注射不同剂量稀土镧,研究小鼠睾丸环磷腺苷(cAMP)和自由基水平的变化。在稀土镧作用下,与对照组相比,处理组小鼠睾丸cAMP含量显著降低(P<0.05);MDA含量显著升高(P<0.05);GSH-PX活力无显著变化(P<0.05)。400mg·kg-1·d-1剂量组睾丸SOD活力显著降低(P<0.05)。腹腔注射稀土镧导致小鼠睾丸cAMP含量和SOD活力降低,可能是导致小鼠精子质量下降的重要原因。     

全氟辛酸致小鼠肝脏氧化损伤的实验

研究了低（1mg/kg/d）、中（5mg/kg/d）、高（25mg/kg/d）三个剂量组全氟辛酸（Perfluorooctanoic acid,PFOA）致小鼠肝脏脂质过氧化损伤的作用.结果发现,PFOA能抑制小鼠体重的增长,对肝组织造成一定的脂质过氧化损伤.各组小鼠出现不同程度的体重增长缓慢甚至减轻,中、高剂量组出现明显的减轻（P＜0.01）;低、中、高剂量组肝脏系数,均明显高于对照组（P＜0.01）;与对照组相比,各剂量组的肝组织中MDA、NO及LDH含量明显增高,SOD、SDH及GSH-Px活性均明显降低（P＜0.05）.     

姜黄素对重离子辐射损伤小鼠睾丸组织的防护作用研究

探讨姜黄素(Curcumin,简称Cur)对重离子辐射损伤小鼠睾丸组织的防护作用。小鼠灌胃不同剂量的Cur后给予4 Gy剂量~(12)C~(6+)离子束全身单次照射。24 h后对小鼠睾丸组织形态学变化进行观察,并测定丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性和过氧化氢酶(CAT)活性。结果显示:中、高浓度Cur预处理组对小鼠睾丸组织的形态具有较好的保护作用;低、中浓度Cur预处理组MDA含量显著降低(P0.05);与单纯照射组相比,低浓度Cur预处理组SOD活性水平和中浓度Cur预处理组CA了活性水平显著提高(P0.05)。结果表明:Cur对重离子全身辐射小鼠的抗氧化系统有一定的激活效应,对辐射损伤有一定的防护作用,其机制可能与Cur清除自由基,保护脂质和蛋白质有关。     

蕨菜醇提取物的抗氧化特性

采用二苯代苦味肼基自由基(DPPH)体系、羟基自由基体系、超氧阴离子自由基体系,对蕨菜醇提取物抗氧化特性进行研究,并同Vc、2,6-二叔丁基对甲酚(BHT)进行比较.结果表明:蕨菜醇提取物对这几种自由基均有不同程度清除作用,对DPPH自由基清除能力最强,当浓度为0.6mg/mL时,清除能力已超过BHT,当醇提物浓度为0.8mg/mL时,清除率已达83.6％,但一直小于Vc.醇提物浓度为15mg/mL时,对羟基自由基的清除率为82.4％,对超氧阴离子清除率为52.6％,在实验浓度范围内,抗氧化性小于Vc和BHT.     

9.4T下TX模型小鼠脑组织的扩散张量成像研究

本文首次应用9.4 T高场磁共振扩散张量成像（diffusion tensor imaging，DTI）技术，研究了Wilson疾病模型TX（toxic milk）小鼠的脑组织微观结构改变和结构连接情况.基于感兴趣区域（region of interest，ROI）的分析发现，与对照组相比，TX模型组的各向异性比值（fractional anisotropy，FA）在海马、尾状核和苍白球显著下降；平均扩散率（mean diffusivity，MD）则呈现上升趋势，但无统计学意义.纤维束追踪法结果表明TX模型组小鼠的脑结构连接并未受到严重破坏，证明了铜累积对脑组织的损伤具有区域性.     

茶多酚对6-OHDA诱导的SH-SY5Y细胞凋亡的保护作用

茶多酚在体内具有广泛的生物活性和药理作用,有助于预防与氧化应激相关的疾病,比如癌症,心血管疾病,神经退行性疾病和衰老. 氧化应激参与了帕金森病（PD）的病理进程. 活性氧在PD的发病机制中发挥了重要的作用,氧自由基直接损伤细胞膜引起脂质过氧化,损伤蛋白质和各种功能酶引起蛋白质沉淀,诱导促凋亡因子的表达,损伤DNA,最终导致了细胞的凋亡. 然而,关于茶多酚对PD的预防和治疗作用目前还不清楚. 本文应用氧化应激诱导的PD病理细胞模型,评价了茶多酚的神经保护作用. 结果表明茶多酚这类植物天然抗氧化剂对氧化应激诱导的细胞凋亡具有明确的抑制作用. 实验中我们选择了6-OHDA诱导的SH-SY5Y细胞作为细胞模型, 运用了MTT、流式细胞术、荧光显微成相, 竞争性ELISA和蛋白质杂交等方法研究了SH-SY5Y细胞的凋亡特性. 结果表明,6-OHDA对SH-SY5Y有时间-浓度依赖性细胞毒性,100 μmol/L 6-OHDA处理24 h,细胞活力减少50 %,同时伴随着活性氧增加（用ＥＳR）,线粒体膜电位降低,细胞内钙离子和一氧化氮增加,nNOS和iNOS表达量上升及蛋白结合的硝基酪氨酸水平升高. 单独茶多酚处理对细胞没有太大的影响,而茶多酚预处理可显著降低6-OHDA所产生的细胞毒性. 溶液实验证明,茶多酚对6-OHDA的自氧化有浓度-时间依赖性抑制作用（用ＥＳＲ）. 本研究表明茶多酚可能是通过活性氧-一氧化氮途径,减少过氧亚硝基的生成来对6-OHDA诱导的细胞凋亡表现保护作用的. 本文的实验结果提示茶多酚在治疗PD等慢性神经退行性疾病上可能是一种有着潜在疗效的药物.     

维生素C片剂的紫外分光光度法测定

在酸性介质中 ,紫外分光光度法测定了果味维生素 C片剂中 Vc的含量。方法的线性范围为 0—1 .4 mg/m L,操作简便、快速 ,重现性好 ,准确度高     

ESR Study in Reactive Oxygen Species Free Radical Production of Pinus kesiya var. langbianensis Heartwood Treated with Laccase

Enzymatic oxidation of lignin phenolic hydroxyl groups can enhance the level of autoadhesion between wood fibers or particles depending upon the bonding mechanism of wood-based materials without synthetic adhesives such as urea and phenol formaldehyde. The adhesive effect is caused by an increased number of reactive oxygen groups at the fiber surface. The parameters of laccase-treated wood fibers play vital roles in generating reactive oxygen species (ROS) free radicals. Laccase I (white-rot fungi) and laccase II (Aspergillus sp.) are used to catalyze the oxidation of heartwood powder of Pinus kesiya var. langbianensis in suspension under different pH values, temperatures, treatment times and different laccase concentrations. Electron spin resonance spectroscopy and spin trapping technique were used to detect the ROS free radicals generated in the laccase-treated heartwood powder and it was found that in it the concentration of ROS free radicals was higher than that in the control. Analysis of variance indicates that there was a significant difference between the ROS concentration values of laccase-treated heartwood powder under different pH values, treatment temperatures and times, and laccase dosages for both laccase I and II. Furthermore, the concentration of ROS free radicals generated by laccase I is higher than that generated by laccase II. It was found that the optimum conditions for generation of ROS in laccase-treated heartwood powder by the two kinds of laccase are pH 3.0; treatment temperature, 50 °C; treatment time, 2 h; enzyme concentration, 20 units/g of wood powder. Authors' address: Xinfang Duan, Research Institute of Wood Industry, Chinese Academy of Forestry, Wan Shou Shan, Beijing 100091, People's Republic of China     

EPR Technology Spectroscopic Investigation of Generation of Reactive Oxygen Species Free Radicals in Laccase-Activated Jute Fiber

Lignins in jute fibers can be activated by laccase to generate reactive oxygen species (ROS) free radicals for subsequent use in radical graft polymerization. The effect of incubation conditions on the generation of ROS free radicals when jute powders were incubated with laccase was investigated through spin-trapping technique to detect the spin adduct of N-tert-butyl-α-phenylnitrone and ROS free radical using electron paramagnetic resonance spectroscopy. Results revealed that the highest concentrations of ROS free radicals were generated when jute was incubated with laccase (0.54 U/mL) and copper ions (10 mM) in solution at pH 3.5 and a temperature of 60 °C for 1 h.     

ESR study on scavenging effect of nicotine on free radicals

Smokers have less risk to catch degenerative diseases such as Alzheimer’s disease and Parkinson’s disease that are both correlated with enhanced oxidative stress. The scavenging effect of nicotine on free radicals was investigated by electron spin resonance techniques. It was found that the scavenging effect of nicotine on hydroxyl radicals and superoxide free radicals was higher than that of vitamin C. It was also found that nicotine could scavenge free radicals in gas-phase cigarette smoke. The data indicate that nicotine may be a potential antioxidant.     

Noninvasive mapping of the redox status in septic mouse by in vivo electron paramagnetic resonance imaging

Increased reactive oxygen species (ROS) contribute to numerous brain disorders, and ROS generation has been examined in diverse experimental models of lipopolysaccharide (LPS)-induced inflammation. The in vivo electron paramagnetic resonance (EPR)/nitroxide spin probe method has been used to analyze the redox status in animal models modulated by ROS generation. In this study, a blood–brain barrier (BBB)-permeable nitroxide spin probe, 3-hydroxymethyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl (HMP), was used as a redox-sensitive nitroxide probe. Magnetic resonance images of mouse head after the injection of HMP showed that HMP was distributed throughout all regions of the mouse head including the brain, suggesting that HMP can reveal redox information in all regions of the mouse head. After the injection of HMP through the mouse tail vein 6 h after the injection of LPS, three-dimensional (3D) EPR images were obtained each minute under a field scanning of 0.3 s and with 81 projections. The reduction reaction of HMP in septic mouse heads was remarkably accelerated compared to that in control mice, and this accelerated reaction was inhibited by aminoguanidine and allopurinol, which inhibit enzymatic activities of induced nitric oxide synthase and xanthine oxidase, respectively. Based on the pharmacokinetics of HMP in mouse heads, the half-life mapping of HMP was performed in LPS-treated mouse head. Half-life maps clearly show a difference in the redox status induced by ROS generation in the presence or absence of inhibitors of ROS-generating enzymes. The present results suggest that a 3D in vivo EPR imaging system combined with BBB-permeable HMP is a useful noninvasive tool for assessing changes in the redox status in rodent models of brain disease under oxidative stress.     

Renal Clearable Luminescent WSe2 for Radioprotection of Nontargeted Tissues during Radiotherapy

High‐energy ionizing radiation is widely used in medical diagnosis and cancer radiation therapy. However, high‐energy radiation can also impose significant damages in healthy tissues during medical treatments via direct DNA damages and indirect damages from production of reactive oxygen species (ROS). Therefore, it is urgent to develop highly effective radioprotectants with low toxicities that can meet the increasing needs for alleviating the adverse effects from cancer radiation therapy and nuclear emergency. In this work, strongly catalytic ultrasmall (sub‐5 nm) cysteine‐protected WSe₂ dots are employed to protect healthy tissues against radiation via diminishing radiation‐induced free radicals. The WSe₂ dots with high surface activities can recover radiation‐induced DNA damages and eliminate the excessive ROS generated from radiation. In vivo experiments confirm that the survival rate of mice treated with WSe₂ dots is significantly elevated with radiation damages postponed under exposure to high‐dose ionizing radiation. Furthermore, the free radicals in major organs and hematological system can be appreciably omitted, suggesting their unique role as free radical scavengers. These WSe₂ dots in ultrasmall size show rapid renal clearance of ≈74% injection dose via urine excretion in 24 h and do not cause any apparent toxicity in vivo for up to 30 d.     

在体电子自旋共振(EPR)波谱和成像技术在生物医学中的应用

活性氧和氮自由基(ROS/RNS)在一系列的人类疾病中扮演着双重角色. 它们可以是氧化剂, 诱导氧化状态, 导致组织损伤. 它们又可以是信号传导因子, 诱发保护性反应, 使得被调节的组织器官经受得起更强的损伤. 鉴于它们在生物医学中的重要作用, 检测它们产生和分布的技术的研究因而变得必要和紧迫. 在体电子自旋共振(EPR)波谱和成像技术渐已被应用于活体生物体系中用以表针和显像ROS/RNS. EPR 波谱特性(包括线宽、强度和寿命)以及空间分布信息已为动物甚至人体病理模型中氧化还原状态和氧分布的检测提供不可缺少的依据. 该文将简单描述和讨论一系列在体EPR 波谱和成像技术在器官和组织中的应用, 其中包括活体组织氧化还原状态, 活体组织氧分布和时间演化, 自由基空间以及谱-空间成像等.     

硒对钝顶螺旋藻氧化损伤的拮抗作用的光谱学特性及机制

研究了亚硒酸钠预处理对H2O2氧化胁迫下钝顶螺旋藻(Spirulina platensis)的生长、藻丝体形态、谱学特性以及细胞内活性氧(ROS)水平的影响,探究硒拮抗氧化胁迫保护螺旋藻的机制。结果显示,H2O2氧化胁迫明显抑制螺旋藻的生长,藻丝体严重受损,可见光吸收440nm峰增强,620和680nm峰降低;荧光发射和激发光谱特征峰强度明显降低,藻胆蛋白特征发射峰由660nm蓝移至650nm;红外光谱透射峰没有发生位移,蛋白质和多肽的特征谱带酰胺Ⅰ带和酰胺Ⅱ带相对强度降低;细胞内ROS相对含量显著性升高。硒预处理24h呈剂量效应地减轻由H2O2胁迫引起的氧化损伤,有效地抑制胞内ROS的过度累积,提高螺旋藻的抗氧化能力,缓解了氧化胁迫对光能捕获和传递等重要生理功能的影响。     

Generation of reactive oxygen species and oxidative stress in <Emphasis Type="Italic">Escherichia coli</Emphasis> and <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> by a novel semiconductor catalyst

The objective of this study was to investigate antimicrobial mechanisms of a new catalytic material (charge transfer auto oxidation–reduction type catalyst, CT catalyst) that may have great potential for application in water/wastewater treatment. Generation of reactive oxygen species (ROS) in bacteria-free solution, induction of ROS and oxidative damage in bacteria (including E. coli and S. aureus) were examined for the CT catalyst. The results showed that significantly higher (p < 0.05, via t-test) amount of hydroxyl radicals was generated by the CT catalyst compared with the control, particularly after 6 h of contact time that more than twice of the amount of the control was produced. The generation of ROS in the bacteria was greater under higher pH and temperature levels, which closely related with the oxidative damage in cells. The results indicated that CT catalyst induced oxidative damage in the bacteria might serve as an important mechanism interpreting the anti-microbial function of the CT catalyst.     

时间分辨ESR与电子自旋极化研究

介绍了近年发展起来的时间分辨TRESR技术，以3个实例介绍了用TRESR研究光解自由基的电子自旋极化的状况，指出研究自旋极化可以得到关于分子激发态和自由基反应动力学等丰富的多方面信息，TRESR技术是研究光与分子相互作用的一种重要手段。     

抗氧化剂抗脂质过氧化机制的ESR研究

以NADH诱导的心肌线粒体损伤体系为模型,在体外用ESR研究了谷胱甘肽(GSH)、超氧化物歧化酶(SOD)及辣根过氧化物酶(HRP)的抗氧化机制.结果表明,低浓度的GSH可部分抑制体系中自由基的生成;SOD与HRP以适当比例共同作用,可完全抑制体系中自由基的生成,较好地防止脂质过氧化的发生.