冬眠哺乳动物心血管机能特点

冬眠动物心血管系统适应于冬眠和激醒过程的特殊生理条件形成了其显著的机能稳定性。我们在总结已有研究的基础提出了冬眠动物心血管系统具有耐低体温,抗主律失常,耐缺氧三大机能特点。这些特点不仅是冬眠动物五非冬眠动物的区别,也是冬眠动物在冬眠季机能强化的方面。     

冬眠与免疫

免疫系统是机体防御机制的重要组份。冬眠季节,冬眠动物免疫系统的结构退化、机能抑制,与动物整体的活动相适应,春季恢复。综述民哺乳动物中枢与外周淋巴器官和免疫反应的季节性变化。对调控免疫系统变化的环境因素和受环境因素影响的内源性生理节律对免疫系统冬眠季节的抑制机理作了介绍,更从冬眠对免疫的抑制联系到冬眠净化机体内外环境、冬眠与肿瘤、冬眠与辐射乃至冬眠与长寿等临床关心的实验研究作了简要介绍。     

哺乳动物的冬眠及其影响因素

冬眠不仅是生物学家研究的热点问题,也是其他领域科学家关注的焦点问题之一。结合最近国外的一些研究结果,阐述了哺乳动物冬眠的定义、冬眠期间的行为和生理表现以及影响冬眠的因素,同时也展望了冬眠在未来科学和医学领域中的价值。     

废用条件下大鼠和达乌尔黄鼠骨骼肌氧化应激和抗氧化防御能力与肌萎缩的比较研究

有鳞类(蛇和蜥蜴)具有较发达的嗅器和犁鼻器,对其不同种类嗅觉结构的认识有助于阐明爬行动物化学感觉的进化。本文采用组织学方法比较了草原沙蜥(Phrynocephalus frontalis)、荒漠沙蜥(P. przewalskii)、密点麻蜥(Eremias multiocellata)和秦岭滑蜥(Scincella tsinlingensis)的嗅器及犁鼻器。结果发现,草原沙蜥的鼻腔较为狭长,秦岭滑蜥呈梨形,其他两种蜥蜴的鼻腔略成圆形。秦岭滑蜥的嗅上皮最厚,其次是密点麻蜥和草原沙蜥,荒漠沙蜥最薄。犁鼻器主要由犁鼻腔、犁鼻感觉上皮、犁鼻神经及蘑菇体等组成,没有腺体。草原沙蜥和荒漠沙蜥的犁鼻腔较为宽阔,密点麻蜥和秦岭滑蜥的较窄。4种蜥蜴的犁鼻感觉上皮均较嗅上皮厚,蘑菇体向后逐渐缩小至消失,犁鼻感觉上皮成闭环状,包围犁鼻腔。密点麻蜥和秦岭滑蜥的犁鼻感觉上皮位于犁鼻器的背侧,蘑菇体位于腹侧;与此不同,两种沙蜥的犁鼻感觉上皮偏向于犁鼻器的腹内侧,蘑菇体位于背外侧。密点麻蜥的犁鼻感觉上皮最厚,其次为秦岭滑蜥,两种沙蜥最薄;秦岭滑蜥犁鼻感觉上皮的感觉细胞密度最高,其次是密点麻蜥,两种沙蜥最低。这些结果提示,密点麻蜥和秦岭滑蜥对嗅觉信号的依赖和投入较两种沙蜥多;4种蜥蜴犁鼻器的结构差异间接地佐证了有鳞类犁鼻器系统发生的特异性。     

生长抑素的生理作用及其与哺乳动物冬眠启动的关系

生长抑素(somatostatin, SS)是一种具有抑制性作用的脑肠肽,在哺乳动物的中枢神经系统及消化系统中广泛分布,具有抑制多种垂体激素的分泌、维持胃肠道功能等重要作用。冬眠是一种低体温和低代谢状态,以全身多器官功能暂时"休止"为特征,依据生长抑素特殊的"刹车"作用,推测其与冬眠启动过程相关。本文综述了生长抑素的生理作用及其与哺乳动物冬眠启动的关系。     

冬眠哺乳动物──天然的心血管医学研究模型

本文在简要概括本实验室和国际研究进展的基础上,归纳提出了冬眠动物心血管系统具有耐低体温、抗心律失常、耐缺氧等几大机能特点,并着重指出,冬眠动物适应于特殊生理条件所形成的心血管系统机能稳定性,及其背后的调节途径,对于医学研究有重要参考价值,因而作者倡导利用我国动物资源,从医学角度研究冬眠动物。     

哺乳动物防御素的研究进展及其应用前景

防御素是生物界广泛存在的一类具微生物抗性的低分子短肽,其中哺乳动物防御素的抗性谱最为广泛,具有很高的应用潜力.概述了哺乳动物防御素的组成分布、立体结构、基因表达调控、抗菌谱等的国内外研究进展,并展望了其在医学和植物抗病基因工程中的应用前景.     

食源性抗氧化肽研究进展

生物活性肽主要水解自食源性蛋白质,此类活性物质表现出多种生物功能,其中尤以抗氧化能力最为突出。多项研究已证实抗氧化成分的摄入与疾病的发生呈逆相关关系。生物活性肽的抗氧化作用主要表现在自由基的清除能力、脂质过氧化的抑制能力以及金属离子的螯合能力。抗氧化活性的强弱取决于活性肽的结构及其特异性氨基酸序列。本文在对氧化应激的发生进行了介绍后,先后阐述了抗氧化肽的益生功能、酶法制备工艺、抗氧化活性的检测方法、生物利用度及其食用安全性。     

哺乳动物滑翔和飞行性状适应性演化研究进展

运动形式的适应性演化与生物的捕食、防御、繁殖和通讯等生存行为紧密相关.哺乳动物演化出的多种多样的运动方式对占领新栖息地和获取新生存资源有着举足轻重的作用,其中滑翔和飞行能力是哺乳动物为适应环境而演化出的特殊运动形式,该类群动物已成为适应性演化研究的热点模型之一.为了适应生存,滑翔和飞行哺乳动物在形态、生理和行为方面都发...     

黄喉拟水龟对冬眠期间急性高温胁迫的氧化应激响应

全球气候变暖加剧,暖冬现象出现的频率及强度不断增加,外温动物冬眠期间将面临更加频繁的高温胁迫。但目前,高温胁迫对爬行动物冬眠期间氧化应激以及抗氧化防御系统影响的研究还较为缺乏。本研究以黄喉拟水龟(Mauremys mutica)南北两个种群的一龄幼龟为研究对象,探究了冬眠期间(6℃)幼龟受高温胁迫(25℃)后的脂质过氧化损伤标志物丙二醛(MDA)含量,以及抗氧化防御和修复系统的超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GSH-Px)的活性变化。结果显示,南种群在经历高温胁迫后肝脏MDA含量高于北种群,且放回6℃冬眠条件恢复24 h后仍在升高;北种群肌肉MDA含量受高温胁迫后上升,但在冬眠温度下恢复24 h后即降至对照水平。两种群SOD活力受高温刺激影响不显著。同时,黄喉拟水龟南种群肝脏中CAT的活力在高温刺激2 h后达到最高,并且各处理组间南种群CAT活力均高于北种群;北种群幼龟肝脏GSH-Px活力在高温刺激12 h达到最高。综上,本研究表明,高温胁迫对冬眠期间黄喉拟水龟机体造成一定的氧化损伤,南方种群可能更易受到冬眠期间温度波动的影响,但南方种群机体具有更强的抗氧化酶活力以应对高温胁迫的威胁。     

超排处理对雌兔生殖器官中表皮生长因子表达的影响

本研究采用免疫荧光组织化学染色法和蛋白免疫印迹法比较研究了后肢去负荷大鼠(Rattus norvegicus)和冬眠不活动达乌尔黄鼠(Spermophilus dauricus)不同类型骨骼肌氧化应激水平和抗氧化防御能力及与肌萎缩之间的关系。结果显示,后肢去负荷14 d后,大鼠比目鱼肌和趾长伸肌肌萎缩程度显著升高,过氧化氢和丙二醛水平增加,Nrf2介导的抗氧化信号通路及下游抗氧化酶蛋白表达及活性显著下降;而冬眠不活动达乌尔黄鼠骨骼肌中肌萎缩指标并未出现变化,氧化应激水平维持夏季组水平,抗氧化酶和调控因子出现不同程度升高。研究表明,后肢去负荷导致非冬眠大鼠骨骼肌氧化应激水平升高,抗氧化防御能力减弱,可能是导致大鼠废用性肌萎缩的重要机制之一;而冬眠动物达乌尔黄鼠骨骼肌在自然废用状态下,抗氧化防御能力增强可能是防止自然冬眠不活动引起的废用性肌萎缩的重要机制。     

The Protective and Antidotal Effects of Taurine on Hexavalent Chromium-Induced Oxidative Stress in Mice Liver Tissue

Acute exposure to hexavalent chromium [Cr(VI)] compounds can cause hepatotoxicity. Reactive intermediates and free radicals generated during reduction process may be responsible for Cr(VI) toxicity. In this study, the effects of pretreatment or posttreatment of taurine on Cr(VI)-induced oxidative stress and chromium accumulation in liver tissue of Swiss Albino mice were investigated. Single intraperitoneal (ip) potassium dichromate treatment (20 mgCr/kg), as Cr(VI) compound, significantly elevated the level of lipid peroxidation as compared with control group (p < 0.05). This was accompanied by significant decreases in nonprotein sulfhydryls (NPSHs) level, superoxide dismutase (SOD), and catalase (CAT) enzyme activities as well as a significant chromium accumulation in the tissue (p < 0.05). Taurine administration (1 g/kg, ip) before or after Cr(VI) exposure resulted in reduction of lipid peroxidation (p < 0.05) showed rebalancing effect on tissue NPSH levels either in pretreatment or in posttreatment (p < 0.05). Enzyme activities of SOD and CAT were restored by taurine pretreatment (p < 0.05), whereas posttreatment had less pronounced effects on these parameters. On the other hand, taurine treatment, before or after exposure, could exert only slight decreases in tissue Cr levels (p > 0.05). In view of the results, taurine seems to exert some beneficial effects against Cr(VI)-induced oxidative stress in liver tissue.     

Venlafaxine Modulates Depression-Induced Oxidative Stress in Brain and Medulla of Rat

Venlafaxine is an approved antidepressant that is an inhibitor of both serotonin and norepinephrine transporters. Medical treatment with oral venlafaxine can be beneficial to depression due to reducing free radical production in the brain and medulla of depression- induced rats because oxidative stress may a play role in some depression. We investigated the effect of venlafaxine administration and experimental depression on lipid peroxidation and antioxidant levels in cortex brain, medulla and erythrocytes of rats. Thirty male wistar rats were used and were randomly divided into three groups. Venlafaxine (20 mg/kg) was orally supplemented to depression-induced rats constituting the first group for four week. Second group was depression-induced group although third group was used as control. Depressions in the first and second groups were induced on day zero of the study by chronic mild stress. Brain, medulla and erythrocytes samples were taken from all animals on day 28. Depression resulted in significant decrease in the glutathione peroxidase (GSH-Px) activity and vitamin C concentrations of cortex brain, glutathione (GSH) value of medulla although their levels were increased by venlafaxine administration to the animals of depression group. The lipid peroxidation levels in the three tissues and nitric oxide value in cortex brain elevated although their levels were decreased by venlafaxine administration. There were no significant changes in cortex brain vitamin A, erythrocytes vitamin C, GSH-Px and GSH, medulla vitamin A, GSH and GSH-Px values. In conclusion, cortex brain within the three tissues was most affected by oxidative stress although there was the beneficial effect of venlafaxine in the brain of depression-induced rats on investigated antioxidant defenses in the rat model. The treatment of depression by venlafaxine may also play a role in preventing oxidative stress. Abstract of the paper was submitted in 1st Ion Channels and Oxidative Stress Congress, 14–16 September 2006, Isparta, Turkey.     

动物抗氧化系统中主要抗氧化酶基因的研究进展

抗氧化系统是机体清除体内多余的活性氧、保护自身免受氧化损伤的重要体系,其中超氧化物歧化酶、过氧化氢酶、谷胱甘肽过氧化物酶等起主要作用。本文将对动物抗氧化系统中,超氧化物歧化酶、过氧化氢酶和谷胱甘肽过氧化物酶基因的种类、分布、结构及表达进行综述。     

Chronic Lithium Treatment has Antioxidant Properties but does not Prevent Oxidative Damage Induced by Chronic Variate Stress

This study evaluated the effects of chronic stress and lithium treatments on oxidative stress parameters in hippocampus, hypothalamus, and frontal cortex. Adult male Wistar rats were divided into two groups: control and submitted to chronic variate stress, and subdivided into treated or not with LiCl. After 40 days, rats were killed, and lipoperoxidation, production free radicals, total antioxidant reactivity (TAR) levels, and superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities were evaluated. The results showed that stress increased lipoperoxidation and that lithium decreased free radicals production in hippocampus; both treatments increased TAR. In hypothalamus, lithium increased TAR and no effect was observed in the frontal cortex. Stress increased SOD activity in hippocampus; while lithium increased GPx in hippocampus and SOD in hypothalamus. We concluded that lithium presented antioxidant properties, but is not able to prevent oxidative damage induced by chronic variate stress.     

Selenium and Vitamin E Modulates Cigarette Smoke Exposure-Induced Oxidative Stress in Blood of Rats

Cigarette smoke contains about 5,000 chemicals that include organic and metallic compounds. The current study was undertaken to investigate the effects of selenium and vitamin E on oxidative stress-induced damage in rats exposed to cigarette smoke. Forty male rats were equally divided into four groups. The first and second groups were used as control and cigarette smoke groups, respectively. Selenium was administered to rats constituting the third group for 27 days. The Se and vitamin E combination was given to animals in fourth group for 27 days. All groups except the control, were exposed to cigarette smoke starting at the third day of the experiment and continuing for 27 days. The blood samples from all groups were taken at the end of 27 days. Plasma lipid peroxidation, triacylglycerol, and total cholesterol levels were higher in the cigarette smoke group than in the control, although erythrocytic superoxide dismutase and glutathione peroxidase activities were lower in the cigarette smoke group than in the control. The plasma lipid peroxidation, triacylglycerol, and total cholesterol levels were lower in cigarette smoke+Se+VE group than in the cigarette smoke group, although erythrocytic superoxide dismutase activity and glutathione peroxidase activity in selenium and vitamin E-administered groups were higher than in the exposed to cigarette smoke group. High-density lipoprotein-cholesterol level was not affect by selenium and vitamin E administrations. In conclusion, selenium and vitamin E seem to have protective effects on the cigarette smoke-induced blood toxicity by supporting the enzymatic antioxidant redox systems.     

氧化应激研究进展及其在缺血性心肌病发病中的作用

缺血性心肌病(ischemic cardiomyopathy,ICM)是指由于长期心肌缺血导致心肌局限性或弥漫性纤维化,从而产生心脏收缩和(或)舒张功能受损,引起心脏扩大或僵硬、充血性心力衰竭、心律失常等一系列临床表现的临床综合症。大量研究表明,ICM的发病机制与氧化应激密切相关。研究和开发新的抗氧化药物,将为缺血性心肌病的防治提供新的方向和途径。     

氧化应激研究进展及其在缺血性心肌病发病中的作用

缺血性心肌病（ischemic cardiomyopathy,ICM）是指由于长期心肌缺血导致心肌局限性或弥漫性纤维化,从而产生心脏收缩和（或）舒张功能受损,引起心脏扩大或僵硬、充血性心力衰竭、心律失常等一系列临床表现的临床综合症。大量研究表明,ICM的发病机制与氧化应激密切相关。研究和开发新的抗氧化药物,将为缺血性心肌病的防治提供新的方向和途径。     

Interactions Between Chronic Stress and Chronic Consumption of Caffeine on the Enzymatic Antioxidant System

We studied the effect of chronic caffeine on parameters related to oxidative stress in different brain regions of stressed and non-stressed rats. Wistar rats were divided into three groups: control (receiving water), caffeine 0.3 g/L and caffeine 1.0 g/L (in the drinking water). These groups were subdivided into non-stressed and stressed (repeated restraint stress during 40 days). Lipid peroxide levels and the total radical-trapping potential were assessed, as well as antioxidant enzyme activities superoxide dismutase, gluthatione peroxidase, and catalase in hippocampus, striatum and cerebral cortex. Results showed interactions between stress and caffeine, especially in the cerebral cortex, since caffeine increased the activity of some antioxidant enzymes, but not in stressed animals. We concluded that chronic administration of caffeine led, in some cases, to increased activity of antioxidant enzymes. However, these effects were not observed in the stressed animals.     

Protective Effects of Lamotrigine,Aripiprazole and Escitalopram on Depression-induced Oxidative Stress in Rat Brain

We investigated the effects of lamotrigine, aripiprazole and escitalopram administration and experimental depression on lipid peroxidation (LP) and antioxidant levels in cortex of the brain in rats. Forty male wistar rats were randomly divided into five groups. First group was used as control although second group was depression-induced group. Aripiprazole, lamotrigine and escitalopram per day were orally supplemented to chronic mild stress (CMS) depression-induced rats constituting the third, fourth and fifth groups for 28 days, respectively. Depression resulted in significant decrease in the glutathione peroxidase (GSH-Px) activity, reduced glutathione and vitamin C of cortex of the brain although their levels and beta-carotene concentrations were increased by the three drugs administrations to the animals of CMS induced depression group. The LP levels in the cortex of the brain and plasma of depression group were elevated although their levels were decreased by the administrations. The increases of antioxidant values in lamotrigine group were higher according to aripiprazole and escitalopram supplemented groups. Vitamin A level did not change in the five groups. In conclusion, the experimental depression is associated with elevated oxidative stress although treatment with lamotrigine has most protective effects on the oxidative stress within three medicines.