线粒体形态结构随增龄的变化

线粒体形态结构随增龄的变化刘永海，吴丽娟，陈清棠随着电镜等新技术的应用，对线粒体的复杂结构已有了全面了解。它含有三羧酸循环、氧化磷酸化及呼吸链等一系列酶系，是细胞的能源中心，因此线粒体与细胞生命活动有着极为密切的关系。线粒体功能随增龄而减退，线粒体电...     

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。     

电针对老年性痴呆模型大鼠海马线粒体酶活性的影响

目的研究电针对老年性痴呆（AD）模型大鼠海码神经元线粒体酶活性的影响，从能量代谢的角度探讨电针治疗AD的部分作用机制。方法以D-半乳糖腹腔注射和Aβ1-40海马注射诱导形成的AD模型大鼠为研究对象，电针“百会”、“涌泉”穴，每日1次，连续20d。以通道式水迷宫测试学习记忆能力的变化，评价电针对AD的治疗效庸；以生化方法检测海马神经元线粒体琥珀酸脱氢酶、Na^＋ -K^＋ -ATP酶、Ca^2＋ -Mg^2＋ -ATP酶的活性。结果电针能有效改善AD模型大鼠学习记忆能力，提高线粒体琥珀酸脱氢酶、Na^＋ -K^＋ -ATP酶、Ca^2＋ -Mg^2＋ -ATP酶活性。结论电针可促进ATP的合成与分解利用，调节线粒体功能，改善AD能量代谢障碍。     

三七总皂苷保护海马区神经元线粒体膜电位的实验研究

目的 研究三七总皂苷对缺血再灌注后海马区神经元线粒体膜电位的保护作用.方法 36只SD大鼠随机分为假手术组、模型组、三七总皂苷组,每组12只.建立大鼠脑缺血再灌注模型,荧光染色流式细胞仪检测各组海马区神经元内游离Ca2+浓度和线粒体膜电位的变化.结果 与假手术组比较,模型组海马区神经元内游离Ca2+浓度明显升高,线粒体膜电位明显降低(P＜0.01);与模型组比较,三七总皂苷组海马区神经元内游离Ca2+浓度明显降低(P＜0.01),线粒体膜电位明显升高(P＜0.05).结论 三七总皂苷能抑制缺血再灌注引起的海马区神经元内Ca2+浓度升高,抑制线粒体膜电位下降,保护海马区神经元线粒体功能,这可能是其抗脑缺血再灌注损伤的作用机制之一.     

缺锌对衰老大鼠海马生长抑素mRNA神经元影响的原位杂交组织化…

目的：为探索缺锌对衰老大鼠海马结构内ＳＳ神经元影响的可能机制，研究缺锌和衰老大鼠海马ＳＳｍＲＮＡ神经元的变化。方法 选用Ｗｉｓｔａｒ雄性大鼠２４只，分为缺锌组（７月龄）、老龄组（２４月龄）和对照组（７月龄），每组各８只，缺锌组以含１０ｍｇ／ｋｇ双硫腙的普食喂养，２ｗ后，采用原位杂交组织化学技术显示海马结构内ＳＳｍＲＮＡ神经元，光镜下计数各组海马内ＳＳｍＲＮＡ神经元的数目，采用图像分析技术测定其灰度     

衰老和缺锌大鼠海马胆囊收缩素神经元数目及免疫反应强度的…

选用Ｗｉｓｔａｒ雄性大鼠２４只，分为缺Ｚｎ组（７月龄）、老龄组（２８月龄）和对照组（７月龄），每组各８只。采用免疫组化ＡＢＣ结合图象分析，观察海马胆囊收缩素（ＣＣＫ）神经数目及其免疫反应强度的变化。结果表明，与对照组相比，缺Ｚｎ大鼠与老龄大鼠海马ＣＣＫ阳性神经元的数目和免疫反应强度均明显降低（Ｐ〈０．０５或Ｐ〈０．０１）。提示衰老过程中海马ＣＣＫ阳性神经元的数目减少，ＣＣＫ免疫反应强度降低；衰老过     

艾灸对衰老模型大鼠海马神经元凋亡蛋白Bcl-2及Bax的影响

目的研究艾灸对衰老模型大鼠海马区神经元中Bcl-2与Bax的影响,从细胞凋亡的角度探讨艾灸治疗衰老的部分作用机制。方法以D-半乳糖皮下注射造成的衰老模型大鼠为研究对象,艾灸神阙穴,每日1次,连续30d。以通道式水迷宫测试学习记忆能力的变化,评价艾灸对衰老的治疗效应;以免疫组化SP法检测海马神经元中Bcl-2和Bax表达。结果与模型组大鼠相比,艾灸组大鼠海马神经元中Bcl-2的阳性细胞数显著增加(P0.05),而Bax的阳性细胞数显著降低(P0.05)。结论艾灸能有效改善衰老可能是通过促进衰老大鼠海马神经元Bcl-2的表达,降低Bax的表达,进而抑制细胞的凋亡,减少神经元的丢失来实现的。     

增龄对大鼠海马N-Shc蛋白的影响

目的 研究不同月龄大鼠海马N-Shc蛋白的表达,以及经氧化应激后N-Shc磷酸化水平的改变随年龄的增加而变化的规律.方法 采用蛋白免疫印迹的方法,分别分析幼年组、成年组和老年组大鼠海马N-Shc蛋白的表达水平,以及经H2O2刺激后N-Shc磷酸化水平的改变.结果 幼年组、成年组、老年组海马N-Shc蛋白的含量依次减少(P＜0.05),但成年组和老年组之间没有显著性差异;H2O2处理后,幼年组、成年组、老年组海马N-Shc蛋白磷酸化水平也依次减少(P＜0.01),而成年组和老年组之间无显著差异.结论 随着年龄的增加,海马中N-Shc蛋白的表达逐渐减少并且N-Shc蛋白的活性逐渐降低.     

衰老大鼠主动脉增龄性重塑及其规律分析

目的探讨年龄对主动脉结构及功能的影响，分析主动脉增龄性重塑的主要表现及变化规律。方法健康Wistar大鼠60只，依月龄分为青年组、成年组、中年组和老年组。各组应用超声方法分别进行主动脉壁厚（ADT）和内径检测，离体动脉环试验测定胸主动脉环对乙酰胆碱（Ach）的最大舒张反应性，以及主动脉形态学和比色法检测主动脉一氧化氮（NO）及活性氧（ROS）水平。结果ADT、主动脉内径变化率（AAD）、收缩压（SBP）、脉压（PP）、NO、ROS、内膜中膜厚度（T）、血管内径（D）、中膜平滑肌相对含量[SMC（Aa％）]、胶原纤维相对含量（Aa％）；血管羟脯氨酸含量（HC）、乙酰胆碱诱导的最大舒张百分比（Emax）与年龄明显相关，并且上述指标在各年龄组随增龄变化速率存在差异。结论增龄性动脉重塑过程并非恒速进行，存在一个缓慢起始、加速进展、减速维持的过程。动脉增龄性重塑表现为功能重塑与结构重塑，功能重塑与结构重塑并非同步变化，功能重塑在成年期已经开始；结构重塑主要发生在中年期。     

缺锌对衰老大鼠海马生长抑素mRNA神经元影响的原位杂交组织化学研究

目的为探索缺锌对衰老大鼠海马结构内SS神经元影响的可能机制，研究缺锌和衰老大鼠海马SSmRNA神经元的变化．方法选用Wistar雄性大鼠24只，分为缺锌组（7月龄）、老龄组（24月龄）和对照组（7月龄）．每组各8只．缺锌组以含10mg／kg双硫腙的普食喂养，2w后，采用原位杂交组织化学技术显示海马结构内SSmRNA神经元，光镜下计数各组海马内SSmRNA神经元的数目，采用图像分析技术测定其灰度值和截面积．结果与对照组相比，缺锌和衰老大鼠海马内SSmRNA神经元的数目和灰度值均明显减少和降低．神经元的截面积无明显变化．结论在衰老状态下，海马结构内SSmRNA神经元的基因表达水平降低，这种变化与衰老过程中机体锌水平的降低有密切关系．     

小鼠大脑皮质和海马结构内胆碱能纤维的分布及增龄变化

用乙酰胆碱酯酶（ＡＣｈＥ）组织化学方法和体视学测量技术，研究胆碱能纤维在小鼠大脑皮质和海马结构内的分布及增龄变化。结果显示，小鼠大脑皮质和海马结构内ＡＣｈＥ阳性纤维呈不同的板层样分布，老年小鼠（２４月龄）额－顶皮质第Ⅲ、Ⅴ层和海马ＣＡ１、ＣＡ３区分子层及齿状回分子层ＡＣｈＥ阳性纤维密度明显低于成年小鼠（１３月龄）和青年小鼠（３月龄）（Ｐ＜０．０１），后两组间除成年小鼠海马ＣＡ３区分子层纤维密度稍低外，其他各区无显著差异（Ｐ＞０．０５）。结果表明，胆碱能纤维在小鼠大脑皮质和海马结构内的分布具有年龄相关性和区域特异性。     

大鼠脑线粒体和突触体外周型苯二氮(艹卓)受体的增龄变化

目的探讨衰老过程大鼠脑组织线粒体和突触体外周型苯二氮[艹卓]受体（PBRs）的动态变化。方法雌性SD大鼠分为乳鼠组、3、12、15、18、24和30月龄组。动物断头后迅速取脑，采用梯度离心法提取大脑皮质线粒体和海马突触体，应用放射配基结合实验测定PBRs结合活力。结果7组比较，皮质线粒体和海马突触体PBRs结合活性差异显著（均P〈0．05～0．001）。15月龄以前皮质线粒体和海马突触体PBRs结合活性逐渐下降（P〈0．01），15～24月龄PBRs结合活性有下降趋势，但变化不显著（P〉0．05）。30月龄组皮质线粒体和海马突触体PBRs结合活性显著高于3月龄组（P〈0．01），低于乳鼠组（P〈0．05）。结论大脑皮质线粒体、海马突触体PBRs结合活性呈明显增龄性改变，PBRs参与了脑老化过程。     

衰老和缺锌大鼠海马生长抑素含量及其阳性神经元的变化

目的 探讨海马结构内生长抑素（ＳＳ）含量及其阳性神经元的增龄变化，并分析这种变化与衰老过程中锌水平的降低的关系。方法 选用Ｗｉｓｔａｒ雄性大鼠４２只，分为锌组（７月龄）、老年组（２４月龄）和对照组（７月龄），每组各１４只。老年组和对照组均普食喂养，缺锌组以含１００ｍｇ／ｋｇ双硫腙的普食喂养。２周后，采用放免分析和原子吸收法，测定每组各８史大鼠海马和血浆ＳＳ含量及血浆锌含量；采用免疫组化ＡＢＣ法结合     

Changes of dopamine-sensitive cyclic AMP-generating system in the rat hippocampus as a function of age

The dopamine (DA) D₁ and D₂ receptors coupled to the 3′,5′-cyclic adenosine monophosphate (cAMP)-generating system were studied in membrane particles of the dorsal hippocampus in 3 (considered to be young), 12 (considered to be adult) and 24 (considered to be old) month male Sprague-Dawley rats. Activation of D₁ receptors with DA, apomorphine or SKF 82526 enhanced accumulation of cAMP in the hippocampus of rats of the three age groups examined. This stimulatory effect was significantly reduced in adult rats. No further changes were noticeable in old animals. D₂ receptors negatively coupled to cAMP generation were demonstrated by incubating hippocampus membrane particles with SCH 23390 plus DA or with D₂ receptor agonists quinpirole or bromocriptine. The D₂ inhibitory effect on cAMP generation was unchanged in the three age groups. No difference was detectable between young, adult and old rats in the activation of cAMP production by forskolin.     

雌性大鼠下丘脑,垂体中γ—氨基丁酸含量的增龄性变化

目的探讨下丘脑和垂体γ－氨基丁酸（ＧＡＢＡ）含量变化与机体老化的关系。方法采用放射受体法测定了老年（２４～３６月龄）、中年（１２～１４月龄）、青年（３～５月龄）及２０日龄雌性Ｗｉｓｔａｒ大鼠下丘脑、垂体中ＧＡＢＡ的含量。结果雌性大鼠下丘脑ＧＡＢＡ含量随增龄而增加，老年组明显高于中年、青年和２０日龄组（Ｐ＜０．０５，Ｐ＜０．００１），中年和青年组明显高于２０日龄组（Ｐ＜０．００１），中年与青年组间无明显差异；垂体中ＧＡＢＡ含量随增龄而降低，４组间均有显著性差异（Ｐ＜０．００１）。结论大鼠随月龄增加，下丘脑抑制性ＧＡＢＡ系统功能逐渐增强，垂体ＧＡＢＡ系统功能则逐渐减弱，这种趋势将导致下丘脑调节的神经内分泌功能衰退。可能与生殖内分泌系统的老化有关     

Calpains抑制剂对离体大鼠海马脑组织切片CA1区神经元缺氧/复氧性损伤的影响

目的研究Calpains抑制剂PD150606对离体大鼠海马脑组织切片CA1区神经元缺氧性损伤的 影响。方法将大鼠海马脑组织切片随机分为单纯缺氧(Con)组(n=6)、PD150606(PD)组(n=10)、二甲亚枫 (DMSO)组(n=8)。Con组的海马脑组织切片应用正常的人工脑脊液(aCSF)在37℃孵育60分钟,而PD组、DM- SO组的海马脑组织切片分别给用含有50μmol／L的PD150606或O.3％DMSO的aCSF孵育60分钟,所有脑片 均缺氧5分钟,复氧60分钟。分别记录用药前及缺氧前膜电位、缓慢去极化的速率、快速去极化时间及快速去极 化的幅度、复氧60分钟神经元的膜电位及神经元对细胞内注入电流及对Schaffer旁路刺激的反应。计算复氧60 分钟海马CA1区PI阳性神经元细胞数。结果PD组神经元的快速去极化时间为(299±43)秒,显著高于DMSO 组的(24.6±73)秒和Con组的(257±25)秒(P均<0.05);PD组8例在复氧60分钟后膜电位逐渐恢复到基础值 水平,并对细胞注入电流及经Schaffer旁路刺激可以产生高幅度、持续时间短的动作电位。此外,PD组海马CA1 区PI阳性神经元死亡数量为(78±15)个／mm,明显少于DMSO组的(180+22)个／mm和Con组的(198±20)个 ／mm(P均<0.05)。结论PD150606可以显著减轻大鼠海马CA1区神经元缺氧性损伤,减少缺氧／复氧后神经 元的死亡,促进复氧后神     

A morphometric study on human muscle mitochondria in aging

Mitochondria are dynamic organelles capable of significant changes of their ultrastructural features according to the tissue-specific energy demands. In human biopsies of vastus lateralis and anterior tibialis muscles from young (25.0 ± 4.4 years), middle-aged (50.4 ± 7.5 years) and old (75.5±3.9 years) healthy volunteers, we carried out a morphometric study on subsarcolemmal and intermyofibrillar mitochondria to assess whether age-related alterations of the morphology of these organelles contribute to the muscle performance decay in aging. By computer-assisted methods, we measured: the average area (MAA), the longer diameter (Dmax) and the ratio perimeter to area (pleomorphic index: Plei) of mitochondria. No significant age-related ultrastructural differences were found either in subsarcolemmal or intermyofibrillar organelles. However, in middle-aged as well as in the old group of patients vs. the young one, MAA and Dmax showed a clear trend to decrease, while Plei showed a marked, age-related tendency to increase. Higher percentages of less pleomorphic organelles were found in the youngest group of patients and this was particularly evident in the subsarcolemmal mitochondrial population. In addition to reporting on discrete aspects of mitochondrial ultrastructure, MAA, Dmax and Plei are closely related to each other and provide a reliable index of the muscle mitochondria adaptive response to age. Thus, we interpret our results as indicating a substantial preservation of muscle mitochondrial ultrastructure during aging.     

Exercise induces age-dependent changes on epigenetic parameters in rat hippocampus: A preliminary study

Regular exercise improves learning and memory, including during aging process. Interestingly, the imbalance of epigenetic mechanisms has been linked to age-related cognitive deficits. However, studies about epigenetic alterations after exercise during the aging process are rare. In this preliminary study we investigated the effect of aging and exercise on DNA methyltransferases (DNMT1 and DNMT3b) and H3-K9 methylation levels in hippocampus from 3 and 20-months aged Wistar rats. The animals were submitted to two exercise protocols: single session or chronic treadmill protocol. DNMT1 and H3-K9 methylation levels were decreased in hippocampus from aged rats. The single exercise session decreased both DNMT3b and DNMT1 levels in young adult rats, without any effect in the aged group. Both exercise protocols reduced H3-K9 methylation levels in young adult rats, while the single session reversed the changes on H3-K9 methylation levels induced by aging. Together, these results suggest that an imbalance on DNMTs and H3-K9 methylation levels might be linked to the brain aging process and that the outcome to exercise seems to vary through lifespan.     

Stereologic study of the sinoatrial node of rats -- age related changes

Changes in the sinoatrial node represent the major mechanism of sudden death in humans, and because of the sparse knowledge about the effects of aging on this structure, light microscopic and quantitative studies of the sinoatrial node were undertaken. Twenty-one hearts were studied, seven rat hearts from each of the following age groups: three months of age, twelve months of age and eighteen months of age. In the stereo logic study, the following parameters were studied: Vv_[nc] and Vv_{[interstitium]} % (the volume densities of the nodal cell and interstitium, determined by the point-couting method), and Nv_[nc](1/mm³) (the numerical density of the nodal cell, determined by the disector method). The mean volume of the nodal cell (V_[nc]) (μm³) was also determined. The comparisons showed that in the oldest animals, the volume density of the nodal cells decreased, while the volume density of the interstitium increased. Although numerical density of the nodal cell per volume of sinus node decreased, the nodal cells displayed increased mean volume with age. In conclusion, the aging process implies changes in the cell and fiber content of the sinoatrial node. This revised version was published online in July 2006 with corrections to the Cover Date.     

Grape seed proanthocyanidin lowers brain oxidative stress in adult and middle-aged rats

There is growing concern over the increasing instances of decline in cognitive abilities with aging in humans. The present study evaluated the benefits of the natural antioxidant, grape seed proanthocyanidin extract (GSPE) in treating the effects of age-related oxidative stress (OS) and accumulation of lipofuscin (LF) on the cognitive ability in rats. Female Wistar rats of 3- and 12-months of age received a daily oral supplement of GSPE until they attained 6- and 15-months of age. During this period, rats were tested for their cognitive ability. At the end of this period, blood glucose and markers of OS were assessed in the hippocampus. GSPE lowered blood glucose, lipid peroxidation, hydrogen peroxide level, and increased protein sulphydryl (P-SH) content in the hippocampus. In addition, GSPE significantly improved cognitive performance in the two age groups. These results demonstrate that the extent of OS-related LF accumulation is reducible by GSPE. They also suggest a critical role for GSPE as a neuroprotectant in the hippocampus and in preventing cognitive loss with aging.