高蛋氨酸饮食对大鼠血管内皮细胞分泌功能的影响

目的:探讨高蛋氨酸饮食对大鼠血管内皮细胞分泌功能的影响。方法:雄性Wistar大鼠随机分为正常饮食对照组(对照组)和高蛋氨酸饮食组(高蛋氨酸组)。对照组喂饲普通饲料,高蛋氨酸组大鼠喂饲含3%蛋氨酸的饲料,共8周。采用高效液相色谱法测定大鼠血浆同型半胱氨酸含量,以MDA、SOD、NO/ET和t-PA/PAI平衡等指标建立研究平台和内皮功能评价体系,同时以扫描电镜观察主动脉弓血管内皮细胞形态。结果:与对照组相比,高蛋氨酸组血浆Hcy含量显著高于对照组,是对照组的2倍以上;血浆MDA和SOD活力显著升高(P<0.05),t-PA/PAI-1和NO/ET比值均显著降低(P<0.05)。扫描电镜显示高蛋氨酸组大鼠内皮细胞呈典型虫蛀样损害,伴有附壁血栓形成和脂质沉积。结论:高蛋氨酸饮食可诱发大鼠高半胱氨酸血症,Hcy可通过氧化应激机制损伤血管内细胞分泌功能,血浆NO/ET和t-PA/PAI-1系统失衡。     

家兔低密度脂蛋白胆固醇增高及同步饮磁处理水时动脉内膜病理学变化的比较研究

目的:观察家兔实验性低密度脂蛋白胆固醇(LDL -c)增高及同步饮磁处理水时动脉内膜病理变化的区别,探讨磁处理水对动脉粥样硬化的预防作用。方法:新西兰雄性大白兔随机分为3组即对照组(NG)、模型组(ASG)和预防组(MWG) ,以高脂饲料复制家兔动脉粥样硬化(AS)模型。MWG家兔喂高脂饲料同步饮磁处理水,分阶段检测各组家兔血浆LDL -c含量并观察其主动脉内膜病理学改变。结果:MWG血浆LDL -c含量明显较ASG降低(P <0 .0 1,MWG主动脉内膜脂质沉积及粥样斑块形成面积较ASG减小(P <0 .0 1,内膜增生程度较ASG减轻(P <0 .0 1)。结论:提示磁处理水在家兔实验性高LDL -c血症及AS的预防中起一定作用。     

豚鼠动脉粥样硬化模型形成机制:LDL-C代谢异常

目的建立豚鼠动脉粥样硬化模型并探讨其形成机制,同时与大鼠进行比较,阐明模型特点及优势。方法应用高脂饲料诱导方法,观察豚鼠和大鼠动脉粥样硬化病变的形成情况。HE染色法分析主动脉内膜-中膜厚度、内膜炎性细胞浸润和内膜表层斑块的形成情况;酶法检测血脂,酶联免疫吸附法测定血清Ox-LDL浓度,实时定量PCR检测肝脏LDL-R mRNA表达的变化,免疫组化检测血管内膜CD36蛋白表达的变化。结果与对照组比较,豚鼠模型组动脉内膜明显增厚,单核细胞、巨噬细胞浸润与聚集增加,大量的泡沫细胞聚集形成斑块,而大鼠模型组未出现类似动脉粥样硬化病理改变。机制研究表明豚鼠较大鼠易于诱发形成动脉粥样硬化原因主要在于豚鼠血清Ox-LDL水平明显升高,肝脏LDL-R mRNA表达下调,动脉内膜CD36蛋白表达明显增强等。结论与大鼠不同,经高脂饲料诱导10周后,豚鼠可形成典型动脉粥样硬化病变,其机制主要在于LDL-C代谢异常。     

低密度脂蛋白胆固醇升高在家兔动脉粥样硬化发生发展中的意义

目的观察低密度脂蛋白胆固醇(LDL-c)对家兔动脉粥样硬化(AS)形成的影响,探讨AS的发生机制。方法以高脂饲料复制家兔实验性AS模型,分阶段检测家兔血清胆固醇(TC)、甘油三脂(TG)、高密度脂蛋白胆固醇(HDL-c)和低密度脂蛋白胆固醇(LDL-c)含量;观察主动脉内膜病理学变化;分析主动脉内膜增生程度及AS斑块面积与血浆脂蛋白水平的相关性。结果高脂组家兔主动脉粥样硬化面积和内膜增生程度明显较对照组增加(P<0.01),血浆LDL-c水平明显较对照组升高(P<0.01);动脉内膜增生程度及AS斑块面积均与血浆LDL-c水平呈非常显著正相关(r=0.837,P<0.001)。结论提示血浆LDL-c水平升高,是致AS发生发展的重要原因。     

别嘌醇对高尿酸血症大鼠血清脂联素的影响

目的观察高尿酸血症大鼠血清脂联素的改变,探讨别嘌醇对高尿酸血症大鼠血清脂联素的影响及意义。方法 36只雄性SD大鼠随机分为3组。使用高酵母膏饲料联合氧嗪酸钾混悬液腹腔注射6周诱导大鼠高尿酸血症模型。别嘌醇治疗组除给予造模剂外同时给予别嘌醇灌胃。6周后处死大鼠,检测血清尿酸、脂联素、一氧化氮,免疫组化法检测大鼠主动脉内膜层eNOS的表达量。结果与正常对照组相比模型组大鼠血尿酸显著升高[(216.0±6.2)vs(45.1±5.6),P<0.05],血清脂联素、一氧化氮及主动内膜层内皮型一氧化氮合酶表达量显著降低[(52.6±7.9)vs(63.6±9.2),(17.2±3.3)vs(24.1±2.0),(38.3±4.5)vs(48.3±4.2),P<0.05]。别嘌醇治疗组血尿酸降低[(44.8±4.3)vs(216.0±6.2),P<0.05],血清脂联素和一氧化氮水平升高[(159.6±9.2)vs(52.6±7.9),(22.1±2.2)vs(17.2±3.3),P<0.05],主动脉内膜内皮型一氧化氮合酶蛋白表达增加[(46.1±4.2)vs(38.3±4.5),P<0.05]。脂联素与一氧化氮呈正相关(r=0.057),与血尿酸呈负相关(r=-0.48)。结论别嘌醇处理可一定程度逆转高尿酸血症可诱导的大鼠血清脂联素的降低,别嘌醇可能是上调内皮型一氧化氮合酶的激动剂。     

葛根异黄酮对去卵巢大鼠骨质疏松症的影响

通过对3月龄Wister大鼠,手术切除双侧卵巢后7天,每天灌胃TIP40mg/kg和10mg/kg,并设去卵巢组(OVX)、假手术组(Sham)和尼尔雌醇阳性对照组(OVX-E2),在给药3个月时,测定大鼠股骨骨矿密度(BMD)、骨钙及血清钙水平等,研究葛根异黄酮(TIP)对由雌激素缺乏引起的骨质疏松症的防治作用。结果TIP40mg/kg的BMD比去卵巢组显著提高了18.1%;使胫骨和血清钙含量显著增加;使去卵巢大鼠的脾脏重量系数和胸腺重量系数明显恢复;并可明显控制大鼠的体重。葛根异黄酮可能具有雌激素样活性,并有改善骨质疏松症的生物学活性。     

2型糖尿病大鼠主动脉硬化模型的构建

目的:建立自发2型糖尿病大鼠主动脉硬化动物模型.方法:用2型糖尿病大鼠主动脉硬化动物模型,44只GK大鼠随机分为正常GK对照组、建模组,每组22只,正常Wistar大鼠组22只.期间观察大鼠血糖、尿糖及一般情况变化,8周后,测定各组动物空腹血糖、总胆固醇(total cholesterol,TC)、甘油三酯(triglycerides,TG)、低密度脂蛋白胆固醇(low density lipoprotein choleste rol,LDL-C),同时光学显微镜观察主动脉结构.结果:模型组大鼠的总胆固醇、甘油三酯、低密度脂蛋白胆固醇明显升高,出现主动脉肥大,病理显示明显的主动脉及动脉内膜病变.结论:通过高脂、一氧化氮合成酶抑制剂,可成功构建自发2型糖尿痛大鼠主动脉病变,用作2型糖尿病大鼠大血管病变研究的动物模型.     

复合生物添加剂对童子鸡饲养效果观察

目的：对绿生元复合生物添加剂、单株好氧芽胞杆菌饲料添加剂对童子鸡的饲喂效果进行了考察。方法,实验分成三组,在全价饲料中各加入不同的添加剂,一组加入单株好氧菌的生物饲料添加刑;二组加入绿生元复合生物添加剂;三组加入抗生素既对照组。每组饲养1400只鸡,添加剂量各为0．1％。从一日龄喂养开始到十周龄结束。结果：一、二、三组死亡率分别为12．5％、8.07％、12．43％;料重比分别为2．587、2.523、2.609。增重成绩对比,实验一、二组相对抗生素组分别是104.6％、108．1％(抗生素组为100％)。结论：绿生元复合生物饲料有明显的促生长效果,增强鸡机体抗病能力,提高养殖经济效益。     

长期低剂量γ线照射和照射加电击对老年前期大鼠性激素、肝功能和脂质过氧化物的影响

本文观察了长期低剂量γ射线照射和照射加电击对老年前期(18～21月龄)大鼠血浆性激素水平、肝微粒体混合功能氧化酶(MFO)活力以及组织脂质过氧化物的影响。长期照射加电击使雄性大鼠血浆睾酮水平明显降低(p<0.05),照射与照射加电击均使雄鼠肝微粒体MFO活力明显下降(p<0.05)。长期低剂量γ射线照射和照射加电击组的睾丸自由基浓度较对照组明显升高(p<0.05),长期照射使雄性大鼠肝匀浆与微粒体,睾丸匀浆与线粒体的脂质过氧化物较对照组明显增高,但照射加电击组的脂质过氧化物较照射组(以及对照组)明显下降。实验结果说明照射与照射加电击对老年前期大鼠的作用有所不同,这些环境因素具有加速老化的作用。     

褪黑素对谷氨酸钠致痫大鼠脑内一氧化氮含量的影响

目的观察褪黑素(Melatonin,MT)对谷氨酸钠致痫大鼠脑内一氧化氮(nitric oxide,NO)含量的影响,研究其抑制癫痫的作用机制。方法40只健康雄性SD大鼠随机分为4组(每组10只):生理盐水对照组(NS组);谷氨酸钠致痫组(Glu组);褪黑素+谷氨酸钠组(MT+Glu组);Luzidole+褪黑素+谷氨酸组(Luz+MT+Glu组)。观察大鼠行为变化,记录脑电图,用NADPH组织化学反应检测大鼠海马内NO含量变化。结果行为学观察和EEG显示,NS组无痫样发作和痫样放电,Glu组和Luz+MT+Glu组痫样发作重(Ⅲ-Ⅴ级),脑电图显示频发高幅的痫样波,MT+Glu组有轻微发作(0-Ⅱ级),脑电图上偶见散在单个微小痫样波;NADPH组织化学反应结果显示,Glu组和Luz+MT+Glu组大鼠大脑皮质及海马内NOS阳性细胞与对照组比较增多,差异性明显(P<0.05),MT+Glu组较Glu组和Luz+MT+Glu组内NOS阳性细胞减少,差异性明显(P<0.05)。结论MT对谷氨酸钠致痫大鼠痫样发作程度、痫样放电有抑制作用,其机制之一是经其特异性受体,减弱NO作用,进而发挥抑痫效应。     

Experimental pathology and pharmacology in brain research and aging

The most important theories on aging are presented and the morphological and neurochemical aspects of the processes of aging in the brain are discussed. Considerably more evidence for specific changes with age can be found on the neurochemical than on the morphological side. The reduction in the capacity of the brain to adapt to metabolic stress situations is a manifestation of the progressive decrease, with advancing age, in the enzyme activity of aerobic energy metabolism.A special section is devoted to the difficulties involved in experimental studies with older laboratory animals, the limited number of species which are suitable for such work (rat, mouse, hamster) and the problems of building up colonies of these older animals.In the last part the significance of the progressive age dependent reduction in the functional tolerance range of oxygen consumption is discussed. Decreased metabolic capacity is part of the reduced adaptability to increased metabolic activity which is characteristic of the aging process. The extensive experimental pathological work carried out on the pathophysiology of ischemia and hypoxia within the framework of experimental brain research has today led to the use of such hypoxia models as screening methods being a prerequisite for the testing of geriatric pharmaceutical preparations in experimental pharmacology.     

Ornithine Decarboxylase in Human Brain: Influence of Aging, Regional Distribution, and Alzheimer's Disease

Abstract: Although experimental animal data have implicated ornithine decarboxylase, a key regulatory enzyme of polyamine biosynthesis, in brain development and function, little information is available on this enzyme in normal or abnormal human brain. We examined the influence, in autopsied human brain, of postnatal development and aging, regional distribution, and Alzheimer's disease on the activity of ornithine decarboxylase. Consistent with animal data, human brain ornithine decarboxylase activity was highest in the perinatal period, declining sharply (by ∼60%) during the first year of life to values that remained generally unchanged up to senescence. In adult brain, a moderately heterogeneous regional distribution of enzyme activity was observed, with high levels in the thalamus and occipital cortex and low levels in cerebellar cortex and putamen. In the Alzheimer's disease group, mean ornithine decarboxylase activity was significantly increased in the temporal cortex (+76%), reduced in occipital cortex (−70%), and unchanged in hippocampus and putamen. In contrast, brain enzyme activity was normal in patients with the neurodegenerative disorder spinocerebellar ataxia type I. Our demonstration of ornithine decarboxylase activity in neonatal and adult human brain suggests roles for ornithine decarboxylase in both developing and mature brain function, and we provide further evidence for the involvement of abnormal polyamine system activity in Alzheimer's disease.     

无瓣海桑果实提取物对衰老小鼠学习 记忆能力的影响及其机制研究

无瓣海桑果实为真红树无瓣海桑的果实。研究无瓣海桑果实不同提取物对D-半乳糖所致衰老小鼠学习记忆能力影响及其作用机制。采用Morris水迷宫实验测量无瓣海桑果实不同提取物对小鼠的学习记忆能力影响,HE染色观察各组小鼠脑部神经细胞的变化情况,并测定脑组织超氧化物歧化酶(SOD)活力、谷胱甘肽过氧化物酶(GSH-Px)活力、一氧化氮(NO)含量和单胺氧化酶(MAO)活力。结果表明:与模型组相比,无瓣海桑果实不同提取物处理组小鼠在水迷宫实验中逃避潜伏期明显缩短(P0.05),目标象限停留时间明显增加(P0.05)。无瓣海桑果实不同提取物处理组小鼠脑部神经细胞损伤与模型组相比明显减少,小鼠脑部SOD酶活力和GSH-Px酶活力提高(P0.05),NO含量和MAO活力在脑部显著降低(P0.05)。无瓣海桑果实不同提取物对D-半乳糖致衰老小鼠学习记忆能力有改善作用,无瓣海桑果实不同提取物通过提高小鼠脑内源抗氧化酶(SOD、GSH-Px)活力,降低脑部NO含量和MAO活力来提高D-半乳糖致衰老小鼠的学习记忆能力。     

Mitochondrial dysfunction in rat brain with aging Involvement of complex I, reactive oxygen species and cardiolipin

Reactive oxygen species (ROS) are considered a key factor in brain aging process. Mitochondrial respiration is an important site of ROS production and hence a potential contributor to brain functional changes with aging. In this study we examined the effect of aging on complex I activity, oxygen consumption, ROS production and phospholipid composition in rat brain mitochondria. The activity of complex I was reduced by 30% in brain mitochondria from 24 months aged rats relative to young animals. These changes in complex I activity were associated with parallel changes in state 3 respiration. H(2)O(2) generation was significantly increased in mitochondria isolated from aged rats. The mitochondrial content of cardiolipin, a phospholipid required for optimal activity of complex I, decreased by 31% as function of aging, while there was a significant increase in the level of peroxidized cardiolipin. The age-related decrease in complex I activity in brain mitochondria could be reversed by exogenously added cardiolipin. This effect of cardiolipin could not be replaced by other phospholipids. It is proposed that aging causes brain mitochondrial complex I dysfunction which can be attributed to ROS-induced cardiolipin oxidation. These findings may prove useful in elucidating the mechanism underlying mitochondrial dysfunction associated with brain aging.     

维尔康对家蝇(Musca domestica)寿命和飞翔肌线粒体年龄变化的影响

本文观察了中药复方维尔康对雄蝇寿命、飞翔肌线粒体能量转换ATP酶(以下简称ATP(?))活性及线粒体超微结构衰老变化的影响。实验表明维尔康可使(?)的群体平均寿命和5％存活时的日龄分别增加11.4％和13.7％,用losrank检验比较对黑组和维尔序组家蝇的生存数据,结果差异极(?)著,P<0.001。对照组家蝇孵化后6日龄ATP酶水解活性最高,随即开始下降。维尔康组家蝇的要(?)活性则一直维持到15日龄以后才开始下降,但其ATP酶活性的年龄交化规律仍与对照组家蝇类似。维尔康组家蝇飞翔肌线粒体超微结构的退化也有较对照组家蝇推迟的趋向。这些现象提示维尔康似可延缓家蝇的衰老过程。     

Oxidative damage increases with age in a canine model of human brain aging

We assayed levels of lipid peroxidation, protein carbonyl formation, glutamine synthetase (GS) activity and both oxidized and reduced glutathione to study the link between oxidative damage, aging and beta-amyloid (Abeta) in the canine brain. The aged canine brain, a model of human brain aging, naturally develops extensive diffuse deposits of human-type Abeta. Abeta was measured in immunostained prefrontal cortex from 19 beagle dogs (4-15 years). Increased malondialdehyde (MDA), which indicates increased lipid peroxidation, was observed in the prefrontal cortex and serum but not in cerebrospinal fluid (CSF). Oxidative damage to proteins (carbonyl formation) also increased in brain. An age-dependent decline in GS activity, an enzyme vulnerable to oxidative damage, and in the level of glutathione (GSH) was observed in the prefrontal cortex. MDA level in serum correlated with MDA accumulation in the prefrontal cortex. Although 11/19 animals exhibited Abeta, the extent of deposition did not correlate with any of the oxidative damage measures, suggesting that each form of neuropathology accumulates in parallel with age. This evidence of widespread oxidative damage and Abeta deposition is further justification for using the canine model for studying human brain aging and neurodegenerative diseases.     

Age-related motor and catecholomine alterations in mice on levodopa supplemented diet

Old mice reared on regular diet show reduced motor activity, decreased basal adenylate cyclase, and increased MAO activities compared to adults. Brain DDC and COMT activities, DA, NE levels and DA-stimulated adenylate cyclase remained unchanged. By contrast, mice fed levodopa for life did not develop decreased motor activity with aging, lived about 50% longer, had slightly elevated whole brain DA and NE levels and failed to develop the expected rise in MAO activity with aging. Levodopa did not alter the number of dopaminergic and muscarinic cholinergic receptors or the adenylate cyclase activity in the striatum during aging. On levodopa, hepatic and renal DA, dopa, and HVA increased but the latter two returned to basal levels by mid life. In liver, DDC was unchanged but MAO tended to be higher in levodopa-fed mice. Thus, motor impairment is an age-related phenomenon in mice associated with selective alterations in brain dopaminergic systems, which may be prevented by dietary levodopa. Extracerebral tissues, through possibly adaptive metabolic mechanisms, play a significant role in regulating brain catecholamines during chronic administration of large doses of levodopa.     

Mitochondrial enzyme activities as biochemical markers of aging

The decrease of neurological performance in normal aging is directly related to brain oxidative stress and inversely related to lifespan. Male mice lifespan was increased by 8-10% (median and maximal lifespan, respectively) in mice with high spontaneous neurological activity, by 21-15% after moderate exercise; and by 25-20% after supplementation with vitamin E. Oxidative stress markers, TBARS and protein carbonyl content, were found increased on aging; a higher content of oxidation products is considered an effective aging factor, specially in the brain, with a majority of postmitotic cells. Mitochondrial enzyme activities, mitochondrial nitric oxide synthase (mtNOS), NADH dehydrogenase and cytochrome oxidase, behaved as markers of brain aging. The decrease in enzyme activities was directly related to the content of oxidation products and to the loss of neurological function in aged mice, this latter was determined in the tighrope and the T-maze tests. The above mentioned conditions that increased mice lifespan were effective to decrease the level of oxidative stress markers, and to retard the decreases in mitochondrial enzyme activities and neurological function associated to aging. The activities of mtNOS, NADH dehydrogenase and cytochrome oxidase may be used as indicators of the effectiveness of antiaging treatments.     

Can Carnosine Prevent the Aging-Induced Changes of Blood Platelet and Brain Regional Monoamine Oxidase-A mRNA in Relation to its Activity?

It is well known that the monoamine oxidase (MAO) activity deregulates during aging along with anti-oxidant activity. Carnosine (β-Ala-l-His) is an endogenous dipeptide biomolecule, having both anti-oxidant and anti-glycating properties. The present study deals with the effect of carnosine on aging-induced changes in MAO-A mRNA expression of brain regions and blood platelets in relation to their MAO-A activity. Results showed that aging significantly and characteristically increased the brain regional MAO-A mRNA whereas, in blood platelets it was significantly reduced with an increase in blood platelet counts. Carnosine attenuated both aging-induced (i) increase in brain regional MAO-A mRNA expression and blood platelet count, (ii) decrease in blood platelet MAO-A mRNA expression and its (platelet MAO-A) activity without affecting the young rats’ brain regions and platelet. The present results thus suggest that carnosine attenuated and restored the aging-induced (a) increase of platelet count and (b) changes in brain regional and blood platelet MAO-A mRNA expression and (c) decrease in platelet MAO-A activity, towards their respective basal level that were observed in young rats.     

Reversal of glial and neurovascular markers of unhealthy brain aging by exercise in middle-aged female mice

Healthy brain aging and cognitive function are promoted by exercise. The benefits of exercise are attributed to several mechanisms, many which highlight its neuroprotective role via actions that enhance neurogenesis, neuronal morphology and/or neurotrophin release. However, the brain is also composed of glial and vascular elements, and comparatively less is known regarding the effects of exercise on these components in the aging brain. Here, we show that aerobic exercise at mid-age decreased markers of unhealthy brain aging including astrocyte hypertrophy, a hallmark of brain aging. Middle-aged female mice were assigned to a sedentary group or provided a running wheel for six weeks. Exercise decreased hippocampal astrocyte and myelin markers of aging but increased VEGF, a marker of angiogenesis. Brain vascular casts revealed exercise-induced structural modifications associated with improved endothelial function in the periphery. Our results suggest that age-related astrocyte hypertrophy/reactivity and myelin dysregulation are aggravated by a sedentary lifestyle and accompanying reductions in vascular function. However, these effects appear reversible with exercise initiated at mid-age. As this period of the lifespan coincides with the appearance of multiple markers of brain aging, including initial signs of cognitive decline, it may represent a window of opportunity for intervention as the brain appears to still possess significant vascular plasticity. These results may also have particular implications for aging females who are more susceptible than males to certain risk factors which contribute to vascular aging.