L-精氨酸对糖尿病大鼠心肌损伤的保护作用

目的探讨L精氨酸(LArg)在糖尿病大鼠心肌损伤的保护作用。方法给大鼠腹腔注射四氧嘧啶制备糖尿病模型,随机分为糖尿病组、LArg组及正常对照组;用药4w末处死大鼠,检测血糖、血胆固醇、血清及心肌组织中SOD、GSHPx、NOS活性和MDA、NO含量以及心肌组织中Na+K+ATPase、Ca2+ATPase活性。结果与模型组比较,LArg可明显降低糖尿病大鼠血糖、血胆固醇水平及MDA含量(均P<0001),显著增加血清GSHPx、NOS活性(分别P<001,P<0001),同时使心肌线粒体GSHPx活性、NO含量明显增加(分别P<005,P<0001),并且使心肌组织中Na+K+ATPase、Ca2+ATPase活性显著增加(P<0001,P<001)。结论LArg在糖尿病性心肌损伤中通过LArgNO通路对心肌损伤具有一定的保护作用,适当补充外源性LArg对糖尿病患者防治心血管系统并发症有重要意义。     

L-精氨酸对糖尿病大鼠心肌损伤影响的实验研究

目的　探讨 L-精氨酸对实验性糖尿病大鼠心肌损伤的保护作用以及在临床用于防治糖尿病性心血管系统并发症的可能性。方法　选用健康纯系 Wister大鼠 ,应用链脲佐菌素制备大鼠糖尿病模型 ,随机分为糖尿病组、L-精氨酸组、正常对照组 ,用药第 8周末处死动物 ,检测外周血及心肌组织的 NO、NOS、SOD、MDA等 ,并取心肌组织作电镜观察 ,研究 L-精氨酸对实验性糖尿病大鼠心肌损伤的影响。结果　 L-精氨酸可以明显降低糖尿病大鼠血糖 (P<0 .0 1 ) ,增加血清中 NO含量及增强 NOS活性 (P<0 .0 5) ;使心肌组织中 SOD增加、MDA减少 (P<0 .0 5)。结论　 L -精氨酸在糖尿病性心肌损伤中通过 L-精氨酸 - NO通路对心肌损伤具有一定的保护作用 ,适当补充外源性 L-精氨酸对糖尿病患者防治心血管系统并发症有重要意义。     

L-精氨酸对糖尿病大鼠睾丸损伤的保护作用

目的 研究L-精氨酸(L-Arg)对糖尿病大鼠睾丸损伤的保护作用及其机制. 方法 电镜下观察L-Arg对STZ诱导的糖尿病大鼠睾丸的形态学改变,并测定睾丸NO、环磷酸鸟苷(cGMP)、内皮素-1(ET-1)、降钙素基因相关肽(CGRP)、丙二醛(MDA)含量及一氧化氮合酶(NOS)、诱导型一氧化氮合酶(iNOS)、SOD、Ca~(2+)-ATPase、Na~+-K~+-ATPase活性,RT-PCR检测睾丸内皮型一氧化氮合酶(eNOS)、iNOS、醛糖还原酶(AR)、CGRP及ET-1 mRNA表达.结果糖尿病组大鼠睾丸电镜下主要见到支持细胞胞质内出现较多空泡,并有大量脂滴沉积,与生精细胞接触处出现空泡;NO、cGMP、CGRP含量及NOS、SOD、Ca~(2+)-ATPase、Na~+-K~+-ATPase活性、CGRP、eNOS mRNA表达均明显低于正常对照组(NC组)(P＜0.05或P＜0.01),而ET-1、MDA含量及AR、ET-1 mRNA表达明显高于NC组(P＜0.01).经L-Arg治疗后,上述改变逆转,与模型组比较,差异有统计学意义(P＜0.05或P＜0.01),电镜下睾丸组织的形态结构接近于NC组. 结论 L-Arg对糖尿病所致的睾丸损伤有一定的保护作用,其机制可能与改善睾丸血供及减轻氧化应激损伤有关.     

L-精氨酸对糖尿病大鼠肾脏、大脑、睾丸氧自由基和抗氧化水平的影响

目的探讨L-精氨酸对糖尿病(DM)大鼠肾脏、大脑、睾丸氧自由基和抗氧化水平的影响.方法给大鼠腹腔注射四氧嘧啶制备DM模型,随机分为DM组、L-精氨酸治疗组及正常对照组;用药4 w末处死大鼠,测定肾脏、大脑及睾丸组织一氧化氮合酶(NOS)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性及一氧化氮(NO)、丙二醛(MDA)含量.结果 DM大鼠睾丸NOS活性(P＜0.01)及大脑、睾丸NO含量(P＜0.05,P＜0.001)、肾脏SOD(P＜0.001)、肾脏、大脑、睾丸GSH-Px活性(P＜0.01,P＜0.001,P＜0.05)均较正常对照组显著降低,而肾脏、大脑、睾丸MDA含量均较正常对照组明显升高(均P＜0.001);L-Arg可显著增加DM大鼠肾脏、大脑、睾丸NOS活性和NO含量(均P＜0.001)及大脑SOD(P＜0.01)、大脑、睾丸GSH-Px活性(P＜0.05,P＜0.001),并使肾脏、大脑、睾丸MDA含量显著降低(分别P＜0.01,P＜0.001,P＜0.001).结论 DM大鼠肾脏、大脑、睾丸组织存在脂质过氧化损伤;L-Arg通过提高NO含量,保护抗氧化酶活性,对DM大鼠肾脏、大脑、睾丸组织的氧化应激有一定的减轻作用.     

L-精氨酸对糖尿病大鼠心肌损伤的影响

目的研究L-精氨酸(L-Arg)对糖尿病(DM)大鼠心肌的保护作用。方法 28只大鼠腹腔注射链脲佐菌素(60 mg/kg)制备DM模型,随机均分为DM组、L-Arg〔300 mg/(kg.d)〕治疗组。另设立正常对照(NC)组(n=12)。用药12周末处死大鼠,用透射电镜观察3组大鼠心肌细胞的形态学改变,采用RT-PCR检测心肌组织内皮型一氧化氮合酶(eNOS)、诱导型一氧化氮合酶(iNOS)、内皮素-1(ET-1)mRNA的表达水平,并测定心肌组织内eNOSi、NOS、Na+-K+-ATP酶、Ca2+-ATP酶活性以及一氧化氮(NO)、ET-1的含量。结果电镜下可见DM组大鼠心肌细胞肌原纤维含量明显减少,肌浆网扩张,线粒体肿胀变性。DM组大鼠eNOS mRNA表达、Na+-K+-ATP酶、Ca2+-ATP酶活性及NO含量明显低于NC组,而ET-1 mRNA表达及ET-1含量明显高于NC组。L-Arg组大鼠心肌病变明显减轻,eNOS mRNA表达、Na+-K+-ATP酶、Ca2+-ATP酶活性及NO含量明显高于DM组,ET-1mRNA表达及ET-1含量明显低于DM组。结论 L-Arg对DM大鼠心肌具有保护作用,其机制可能与L-Arg增加心肌组织NO含量、降低ET-1含量,改善心肌血供有关。     

L-精氨酸对糖尿病大鼠肝损伤的保护作用

目的探讨L-精氨酸(L-Arg)对糖尿病大鼠肝脏损伤的保护作用。方法给大鼠腹腔注射四氧嘧啶制备糖尿病模型,随机分为糖尿病组、L-Arg治疗组及正常对照组;用药4周末处死大鼠,检测肝细胞线粒体超氧化物歧化酶(Mn-SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性及丙二醛(MDA)含量,肝组织细胞一氧化氮合酶(NOS)、Na -K -ATPase、Ca2 -ATPase活性以及NO含量。结果与正常组比较,糖尿病组大鼠肝细胞线粒体Mn-SOD、GSH-Px活性明显降低,MDA含量显著升高,肝组织细胞内NOS、Na -K -ATPase、Ca2 -ATPase活性明显降低;与糖尿病组比较,L-Arg治疗组大鼠肝细胞线粒体Mn-SOD、GSH-Px活性明显升高,且肝组织细胞内NOS、Na -K -ATPase、Ca2 -ATPase活性及NO含量显著升高。结论L-Arg对糖尿病大鼠肝脏损伤具有一定的保护作用。     

磷脂对自由基损伤的心肌线粒体的保护和修复作用

报道磷脂类（卵磷脂及心磷脂）对氧自由基损伤的心肌线粒体的保护及修复作用。应用黄嘌呤氧化酶／次黄嘌吟自由基诱生系统作为自由基损伤体系。预先在心肌线粒体系中加入磷脂可以降低自由基引起的心肌线粒体的膨胀，过氧化脂质的堆积，保护细胞色素氧化酶的活力。这可能因为自由基对心肌线粒体的损伤导致了线粒体膜上卵磷脂及心磷脂的破坏。在体系中外加卵磷脂及心磷脂可作为氧化损伤的直接目标，保护了细胞器的正常结构和功能。同时     

超氧化物歧化酶与L-精氨酸联合预处理对大鼠肝缺血再灌注损伤的保护作用

目的观察L-精氨酸(L-Arg)和超氧化物歧化酶(SOD)两者分别应用和联合应用在大鼠肝缺血再灌注损伤(I/R)中的作用及其机制。方法将大鼠随机分为假手术组、I/R组、L-Arg预处理组(L-Arg组)、SOD预处理组(SOD组)、L-Arg和SOD联合预处理组(L-Arg+SOD组)。治疗组大鼠肝缺血前分别及联合给予L-精氨酸和SOD,再灌注后分别分析血液丙氨酸转氨酶(ALT),天冬氨酸转氨酶(AST)水平;切取肝脏组织测一氧化氮合酶(NOS)、一氧化氮(NO)、丙二醛(MDA)含量;组织病理学观察肝细胞各种病理变化。结果治疗组ALT、AST活性较I/R组有所降低(P0.05),L-Arg+SOD组降低更明显(P0.05)。和I/R组相比较,治疗组e NOS的表达、NO的量增加(P0.05),诱导型NOS(i NOS)表达增加不明显,和I/R组相比较却有所降低,MDA含量显著降低(P0.05),以上各项指标在各治疗组中均以L-Arg+SOD组变化更明显(P0.05)。I/R组示肝组织破坏明显,治疗组明显改善。结论 SOD与L-精氨酸均能够对大鼠肝I/R损伤具有保护作用,两者联用效果更好。     

L-精氨酸甲酯对大鼠结肠炎性损伤的保护作用

目的 了解L-精氨酸甲酯(L-NAME)作为NOS抑制剂,对大鼠结肠炎性损伤的保护作用。方法：将实验大鼠随机分为对照组、损伤对照组、NAME1、NAME2、NAME3(即N1、N2、N3)组,实验采用三硝基苯磺酸(TNB）30mg 50％乙醇0．25ml给大鼠灌肠的结肠炎模型,并检测各组的溃疡指数(UI)、一氧化氮(NO)、MDA、GSH值。结果：1．N1、N2、N3组的NO、UI、MDA值低于损伤对照组,GSH值高于损伤对照组,对照组的损伤不明显。2．相关分析表示,NO与MDA存在正相关,与GSH存在负相关关系。结论：在结肠炎症反应中,NO过量生成具损伤作用;L-NAME通过抑制NOS活性,减少NO生成,具有一定的保护作用。     

增龄对大鼠心肌线粒体DNA氧化损伤的影响

目的　探讨增龄对大鼠心肌线粒体 DNA(mt DNA)缺失、线粒体呼吸链酶复合体及 ATP合成的影响。方法　 Wistar雄性大鼠分为 3组 :幼年组 (1月龄 )、青年组 (6月龄 )各 1 2只和老年组 (2 4月龄 ) 1 0只。心肌线粒体 DNA缺失、线粒体呼吸链酶复合体及腺苷三磷酸 (ATP)合成分别用聚合酶链反应 (PCR)、酶动力学和生物发光技术进行测定。结果　 3组大鼠均有不同程度 mt DNA缺失。老年组 mt DNA缺失 (2 .0 9± 1 .62 )较幼年组 mt DNA缺失 (0 .77± 1 .1 6)明显增高 (P<0 .0 5) ;较青年组 mt DNA缺失 (1 .54± 1 .1 7)也有升高的趋势 (P>0 .0 5)。老年组心线粒体呼吸链复合酶 活力 (2 347.2 1± 62 3.33)均较青年组 (3 859.1 2± 70 3.53)、幼年组 (4776.90± 548.63)明显降低 (P<0 .0 1 )。老年组心线粒体 ATP合成量 (1 96.95± 33.2 6)较青年组 (337.53± 62 .1 8)明显降低 (P<0 .0 1 )。心线粒体呼吸链复合酶 活力 3组间无明显性差异 (P>0 .0 5)。结论　大鼠线粒体 DNA氧化损伤与衰老有一定的相关性。     

超氧化物歧化酶对链脲佐菌素诱发糖尿病自由基代谢的影响

给链脲佐菌素诱导的糖尿病模型大鼠以超氧化物歧化酶（ＳＯＤ），观察其自由基代谢改变，结果表明，ＳＯＤ对改善糖尿病模型大鼠自由基代谢异常有作用。     

Effect of graded corticosterone treatment on aging-related markers of oxidative stress in rat liver mitochondria

Caloric restriction (CR) decreases aging rate and lowers the rate of reactive oxygen species (ROS) production at mitochondria in different organs, but the signal responsible for this last change is unknown. Glucocorticoids could constitute such a signal since it is well known that their levels increase during CR, and available studies failed to find consistent effects of insulin, the other better described hormone that varies during CR, on mitochondrial oxidative stress. In addition, there is almost no information on the possible in vivo effects of glucocorticoids on specific markers of mitochondrial and tissue oxidative stress. In this investigation, male Wistar rats were treated with corticosterone at doses of 150 and 400 mg/kg of diet during 4 weeks. After that time, oxidative stress-related parameters were measured in the liver. The corticosterone treatments did not change the rate of ROS production or the rate of oxygen consumption of rat liver mitochondria. The two lipoxidation protein markers measured (malondialdehyde-lysine and carboxymethyllysine) were decreased by both corticosterone treatments. These changes were associated with decreases in fatty acid unsaturation, especially with lowered levels of the highly unsaturated araquidonic and docosahexaenoic acids, which decrease the sensitivity to lipid peroxidation processes. The specific protein carbonyl glutamic semialdehyde, a marker of protein oxidation, was also lowered at 400 mg/kg corticosterone. The protein glycoxydation marker carboxyethyllysine and the level of oxidative damage to mtDNA (8–oxo-7,8-dihydro-2 9-deoxyguanosine) were increased by corticosterone. The results do not support the idea that corticosterone is the signal responsible for the decrease in mitochondrial ROS generation during CR. However, they show that this hormone modulates the level of oxidative stress both in proteins and in mtDNA. Some of these changes can contribute to the chronic effects of the hormone at tissue level.     

D—半乳糖衰老大鼠自由基代谢状况分析

目的 建立大鼠D-半乳糖衰老模型,检测其脑、胃、肝、大肠、小肠细胞浆及线粒体自由基代谢相关指标（SOD、CAT、XOD、MDA、ONOO^-）。方法 引用模糊综合分析的数理统计方法,与对照组比较,对以上脏器细胞浆及线粒体自由基代谢相关指标进行模糊综合分析。结果 发现线粒体SOD、CAT、XOD、MDA、ONOO^-的综合作用对衰老有影响,影响程度为45%;而细胞浆SOD、CAT、XOD、MDA、ONOO^-的综合作用对衰老影响较小,影响程度为40%。通过检测脑细胞蛋白质羰基含量,发现该模型脑细胞蛋白质羰基含量显著升高,经中药复方治疗后其脑细胞浆蛋白质的羰基含量明显降低。结论 自由基代谢变化可能仅是D-半乳糖衰老大鼠的表现或机理之一,说明自由基衰老理论不能完美解释该模型。初步认为该模型可能包含羰基毒化机制。自由基代谢的改变可能是脑细胞蛋白质羰基化的主要原因,此外D-半乳糖衰本身亦可能致该模型大鼠脑细胞蛋白质羰基化。     

硒谷胱甘肽过氧化物酶保护心肌作用机制

通过人工半合成及天然低成饲料喂养豚鼠，在出现组织硒水平及谷胱甘肽过氧化物酶（ＧＰ）活性明显降低同时，动物红细胞、心肌细胞等的膜结构出现异常，膜脂组成中的磷脂减少．代表细胞膜老化指数的胆固醇／磷脂的分子比增加，作为心肌线粒体内膜必需界面脂的心磷脂明显减少，线粒体能量转换的关键呼吸酶．细胞色素氧化酶（ＣＣＯ）活性明显降低，同时代表其二级结构的园二色谱异常，２０８ｎｍ峰及２２４ｎ峰明显降低．各型脂质过氧化产物，如代表膜磷脂自由基氧化损伤初级产物的脂氢过氧化物、续发产物的丙二醛、呼气烷烃和脂过氧化物聚集产物的荧光色脂均明显增加。这可能正是３０多年前Ｎｅｕｂｅｒｔ等（１９６２）提出ＧＰ对细胞膜的保护作用，尤其所谓线粒体“收缩因子”（“Ｃｏｎｔｒａｃｔｉｏｎ　ｆａｃｔｏｒ”）作用的机制所在。     

车前子多糖对大鼠肝线粒体自由基防御功能的影响

目的探讨车前子多糖(PSP)对大鼠肝线粒体自由基防御功能的影响。方法差速离心法提取雄性SD大鼠肝线粒体,采用硫酸亚铁-维生素C(Fe2+-Vit C)激发剂,建立大鼠肝线粒体脂质过氧化(LPO)模型,比色法测定丙二醛(MDA)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、过氧化氢酶(CAT)和抗氧化物酶(T-AOC)活性,观察PSP对各生化指标的影响。结果 PSP浓度在25、50和100 mg/L范围时,MDA含量分别为3.94±0.15,3.65±0.18和2.88±0.20,均显著低于模型组6.47±0.48(P<0.01),表明PSP对肝线粒体脂质过氧化有抑制作用,而对抗氧化物酶类活性均有激活作用,与模型组比较,均明显升高(P<0.01)。结论 PSP对大鼠肝线粒体自由基的防御功能可产生一定的影响,对治未病起到一定的防治作用。     

自由基在慢性氟中毒大鼠肾脏损伤中的作用

目的 用电子自旋共振（ESR）法直接检测自由基含量,研究慢性氟中毒大鼠肾脏损伤与自由基的关系,从而确定自由基在肾脏损伤中的作用。方法 Wistar大鼠分为3组。正常对照组,未作任何处理;染氟组,自由饮用含氟化钠132.6mg/L的含氟水;抗氧化中药治疗--染氟组,自由饮用132.6mg/L的含氟水,同时每日经腹腔内注射抗氧化中药丹参绞股蓝复方3.125ml/kg,实验6个月时检查动物。结果 与正常对照组相比,自由基,染氟组明显升高,抗氧化中药--染氟组则无明显差异;血、肾超氧化物歧化酶（SOD）、谷胱苷肽过氧化物酶（GSH-Px）活性,染氟组明显降低,抗氧化中药--染氟组则无明显变化;丙二醛（MDA）,染氟组明显升高,抗氧化中药--染氟组则无明显改变;电镜下见染氟大鼠肾小管上皮细胞内线粒体肿胀,嵴变短、溶解、消失,有巨大线粒体,内质网扩张,粗面内质网核糖体脱落等变化。抗氧化中药处理的染氟组未见肾脏病变。结论 氟中毒的肾脏病变可能是自由基损伤的结果。     

Exercise and oxidative stress: Sources of free radicals and their impact on antioxidant systems

Strenuous exercise is characterized by increased oxygen consumption and the disturbance between intracellular pro-oxidant and antioxidant homeostasis. At lease three biochemical pathways (i.e., mitochondrial electron transport chain, xanthine oxidase, and polymorphoneutrophil) have been identified as potential sources of intracellular free radical generation during exercise. These deleterious reactive oxygen species pose a serious threat to the cellular antioxidant defense system, such as diminished reserves of antioxidant vitamins and glutathione. However, enzymatic and non-enzymatic antioxidants have demonstrated great versitility and adaptability in response to acute and chronic exercise. The delicate balance between pro-oxidants and antioxidants suggests that supplementation with antioxidants may be desirable for physically active individuals under certain physiological conditions by providing a larger protective margin.     

Effects of alloxan diabetes and insulin on morphology and certain functional activities of mitochondria of the rat liver and heart

Summary The authors studied the ultrastructural appearance and metabolic behaviour of mitochondria in the liver and heart of rats suffering from alloxan diabetes. Liver mitochondria did not show significant morphological and biochemical changes compared to normal, whereas heart mitochondria were decreased in number, their structure was altered and the phosphorylating activity was obviously impaired. Insulin treatment significantly improved the P/O ratio although, as far as the myocardium was concerned, it could not normalize it. The differences in behaviour of liver and heart mitochondria related to the changes of lipid and carbohydrate metabolism and to the disordered ion balance occurring in this experimental endocrine disease, are discussed. This work was in part supported by a grant from theConsiglio Nazionale delle Ricerche (Rome).     

Insulin stimulates Akt translocation to mitochondria: Implications on dysregulation of mitochondrial oxidative phosphorylation in diabetic myocardium

Mitochondrial oxidative phosphorylation is the major source of energy in cardiac muscle. In the streptozotocin-induced diabetic (STZ-DM) mice, myocardial oxidative phosphorylation was perturbated and oxidative phosphorylation complex V (ATP synthase) activity was significantly reduced. To determine the independent effects of hyperglycemia and insulin deficiency on the changes of myocardial complex V, we used phlorizin (Ph) to normalize blood glucose in the diabetic mice. Ph treatment did not improve myocardial complex V activity in the STZ-DM mice, whereas insulin treatment normalized myocardial complex V activity in the diabetic mice. Therefore, the reduction of complex V activity was caused by insulin deficiency and not by hyperglycemia in STZ-DM myocardium. Acute insulin stimulation induced phosphorylation of Akt and translocation of Akt to mitochondria in myocardium. Translocation of phospho-Akt to mitochondria was enhanced in the STZ-DM mice and was blunted in the diet-induced diabetic mice. In parallel, insulin activation of complex V was enhanced in the STZ-DM myocardium and suppressed in the diet-induced diabetic myocardium. In vivo inhibition of Akt blocked insulin stimulation of phospho-Akt translocation and blunted activation of complex V. Insulin-activated Akt translocation to mitochondria in cardiac muscle is a novel paradigm that may have important implications on myocardial bioenergetics.