维生素与自由基

自由基是机体代谢的中间产物,适量的自由基对抗局部感染有一定的作用,但在疾病、应激、特殊生理等情况下会产生过多的自由基,对机体健康和生产性能带来消极的影响。笔者就自由基对动物体的损害与几种主要的抗氧化性维生素的去自由基作用进行了综述。     

病毒感染与自由基的相互作用

近年来,在基础医学和生命科学领域对自由基的研究已成为一个热点.随着研究的不断深入,自由基已经介入到许多病毒感染性疾病的致病过程,对疾病的发生、发展起着重要作用.病毒可诱导宿主细胞产生氧化应激,释放大量活性氧自由基,在活性氧自由基的作用下病毒复制增强.同时过多的自由基作用于机体,会造成生物膜的脂质过氧化损伤,引起酶、氨基...     

活性氧自由基在动物机体内的生物学作用

自由基是近年来在基础医学和生命科学领域的研究热点,研究较多的以氧(O)、碳(C)和氮(N)为中心的活性基团。其中活性氧是机体内最常见自由基,也是近年来对其体内外生物学作用阐述最多的自由基种类之一。正常情况下,该类自由基在抗菌、消炎和抑制肿瘤等方面具有重要意义。但是,在疾病或某些外源性药物和毒物入侵后,机体抗氧化体系可能会发生紊乱,自由基代谢平衡因此失调,从而导致生物膜和大分子物质发生脂质过氧化损伤。文章对活性氧自由基在动物机体内的产生、性质和生物学作用,以及天然清除剂在机体内对自由基的抗氧化作用、自由基与疾病间的关系做了较全面综述。     

氧自由基与鸡球虫感染

近年来，自由基在生物体系中的作用已成为生命科学的研究热点之一。体内产生的自由基以氧自由基（Oxygen FreeRadicals，OFR）为主，约占95％，对机体危害亦最大。在正常的生理状况下，生物体内的自由基不断产生，也不断被清除，维持在低水平的平衡浓度，不仅对机体无害，还有独特的生理作用。在疾病的情况下，机体体内OFR产生过多或机体清除OFR能力减弱，则可产生MDA等，     

氧自由基与鸡球虫感染

近年来，自由基在生物体系中的作用已成为生命科学的研究热点之一。体内产生的自由基以氧自由基（Oxygen FreeRadicals，OFR）为主，约占95％，对机体危害亦最大。在正常的生理状况下，生物体内的自由基不断产生，也不断被清除，维持在低水平的平衡浓度，不仅对机体无害，还有独特的生理作用。在疾病的情况下，机体体内OFR产生过多或机体清除OFR能力减弱，则可产生MDA等，     

对实验性兔病毒性出血症病例的血清及组织中脂质过氧化物的分析

兔病毒性出血症(又称兔瘟)是由病毒引起的一种急性出血性传染病,对养兔业危害极大。但对兔瘟病毒致病作用的研究却很少。目前在人类疾病研究中,人们越来越重视自由基对机体的损伤。证明了自由基对机体的损伤主要通过对核酸、蛋白质、糖和脂     

自由基对动物的危害及消除技术研究进展

自由基是动物体代谢的正常产物,动物处于正常生理状态时,自由基通常保持稳态。当动物体内自由基的动态平衡遭到破坏时,过量的自由基会对动物机体造成损伤,危害动物健康,甚至引起疾病。文章总结了动物机体自由基的产生机理以及危害,系统分析了自由基产生与饲料养分之间的关系,同时对几种饲料活性物质降低自由基对动物体危害的研究进展进行了综述。     

动物体内氧自由基的产生及危害

氧自由基可引起动物体衰老及疾病的产生。自由基在体内主要通过酶促和非酶促反应产生 ,且自由基的产生是相互关联的。本文简述了超氧阴离子等 5种氧自由基在体内的产生方式及其对机体脂肪、DNA、蛋白质的危害     

复方女贞子多糖对雏鸡抗氧化功能的影响

自从Hammer提出衰老的自由基学说以来,大量的研究发现,临床许多疾病与机体的自由基损伤有关.在正常情况下,机体内的自由基处于动态平衡中,但是一旦该平衡被打破,就会对机体造成损害,从而引发一系列相关疾病[1].     

植物精油抗氧化作用机制研究进展

氧化应激是对动物生产造成巨大经济损失的常见问题之一,它是机体自由基产生增多或(和)清除能力下降,引起机体氧化系统和抗氧化系统紊乱,导致自由基在体内蓄积而引起的氧化损伤过程。氧化应激产生之后会对畜禽的生产性能和健康程度产生负面影响。因此,找到有效的外源性抗氧化剂对畜禽的健康生产有重要意义。植物精油作为天然抗氧化剂,具有安全、高效的特点,其在动物生产中的应用已成为研究热点。文章在简述自由基与氧化应激的基础上,对植物精油的抗氧化作用机制进行了分析和总结。     

病毒感染与细胞核转录因子-κB信号转导的相互作用关系

自发现细胞核转录因子-κB(NF-κB)以来,人们对其分子生物学特征、作用机制及其与疾病的关系作了广泛的研究。近年来的研究结果发现,NF-κB在病毒感染与疾病发生的过程中发挥着重要作用。病毒感染真核细胞时能诱导NF-κB从细胞质转移到细胞核,从而诱导一些炎性基因转录产生大量炎性因子引起炎症反应,或阻碍细胞凋亡促进其自身在宿主细胞内的复制,或促进某些原癌基因的表达使细胞癌化等。不同病毒感染机体时,都会通过对NF-κB信号转导的影响,改变机体的某些性状,导致疾病的产生。目前已发现应激刺激、细菌脂多糖、病毒、氧自由基等很多因素能激活NF-κB,而后通过NF-κB信号转导通路的桥接作用影响机体的新陈代谢,文章就病毒感染与细胞NF-κB信号转导的相互作用关系作一综述。     

Nrf2-ARE信号通路在机体氧化应激损伤中的作用及与其他信号通路的关系

氧化应激损伤与机体中多种疾病的发生与发展过程密不可分,当机体产生严重氧化应激时,抑制氧化应激和清除氧自由基是治疗机体产生疾病的重要策略。Nrf2-ARE信号通路是机体内极为重要的内源性防御体系,通过调控Nrf2-ARE信号通路可起到维持机体细胞内氧化还原状态平衡和降低氧化应激造成损伤的作用。综述了Nrf2-ARE信号通路调控机体抗氧化酶活性、与机体氧化应激相关疾病的相关性及其与其他信号通路的关系,以期为深入了解Nrf2-ARE信号通路在抵抗机体产生氧化应激损伤的作用和机制方面提供参考。     

Relationship among insulin-like growth factor-I,blood metabolites and postpartum ovarian function in dairy cows

The relationship among nutritional status, systemic insulin-like growth factor-I (IGF-I) and ovarian function early postpartum were investigated. A total of 27 Holstein-Friesian cows, 10 that cycled normally within 20 days postpartum, 5 diagnosed with follicular cysts, 8 with persistent corpus luteum (CL) after the first ovulation postpartum and 4 with inactive ovaries were used for the study. Blood samples were collected 1-3 times per week, for 60 days pre- and postpartum, for IGF-I, progesterone, estradiol, free fatty acids (FFA), blood urea nitrogen (BUN), and aspartate aminotransferase (AST) determination. Inactive ovary and cystic cows had a higher body condition score before calving and lost more condition than normal or persistent CL cows. Immediately postpartum, IGF-I levels were higher and rose sharply in cows that cycled normally than in cystic, inactive ovary or persistent CL cows. At calving and early postpartum, FFA was higher in inactive ovary and cystic than in normal and persistent CL cows. There was a significant strong positive relationship between IGF-I and BUN, and strong negative relationships between IGF-I and FFA and AST in all groups. There was a positive relationship between serum IGF-I and estradiol in normal cystic and inactive ovary cows. This study found that overconditioned cows during the dry period or at calving, lost more body condition postpartum. These cows also had a deeper and longer period of negative energy balance (NEB), poor liver function and low circulating IGF-I concentrations early postpartum. Such cows were likely to have poor reproductive function as seen in development of cystic ovaries, persistent CL and inactive ovary. Changes in serum IGF-I early postpartum may help predict both nutritional and reproductive status in dairy cattle.     

Leptin生物学功能的研究进展及其应用前景

国外大量数据资料分析表明 ,Leptin可以降低脂肪、改变体组成、维持能量平衡、提高抗应激能力和免疫机能、促进动物新陈代谢 ,从而提高畜禽的生产性能和经济效益。本文从调控机制、抗性、能量平衡、繁殖等4个方面综述了Leptin生物学功能的研究进展 ,并从神经内分泌和分子生物学水平探讨了其作用机理 ,指出了在畜牧业上的应用前景     

日粮阴阳离子平衡在奶牛生产中应用的研究进展

日粮中的阴、阳离子对奶牛的正常生产和健康有着重要的意义,它们不仅影响奶牛体液的酸碱平衡和渗透压、机体的代谢活动及多项生理指标,而且在奶牛不同的生理阶段,适宜的日粮阴阳离子平衡能提高奶牛的采食量、生产性能,还能有效预防奶牛的产后瘫痪等疾病。作者现就日粮阴阳离子平衡(dietary cation anion balance,DCAB)在奶牛上的应用进行综述,为生产实践中合理应用提供一定的理论基础。     

Potential for control of oxidative injury by administration of antioxidants in veterinary medicine

Cellular metabolism results in the production of reactive oxygen species otherwise known as free radicals. When not kept under control these molecules cause damage to various compartments in cells. These molecules are kept in check with antioxidant compounds that can be endogenous to cells or are present in the diet. When this balance is in the favor of reactive oxygen species then the physiological condition is considered to be in oxidative stress, which can lead to oxidative injury in various tissues. There has been a lot of interest in the effects of free radicals and the various degenerative diseases. This interest has lead to theories such as the free radical theory of aging, which states that aging is the accumulation of damage over time that leads to degenerative diseases. This has lead to a host of interest in the interaction of oxidative damage and certain disease states and how antioxidants may be beneficial in helping to modulate various disease states. In order to understand the potential for controlling oxidative injury in veterinary medicine, one needs to understand the cellular processes that reactive oxygen species and antioxidant compounds play in the body. It is usually thought that oxidative injury results in oxidative damage to the lipid, protein, and DNA components of cells. This damage results in alterations in cellular function. Various antioxidant compounds function to scavenge free radicals before they are able to damage the various cellular components     

Oxidative stress and redox regulation on in vitro development of mammalian embryos

Many factors affect development of mammalian preimplantation embryos in vitro. It is well known that in vitro development of bovine embryos is highly affected by culture condition including energy source, growth factors, pH or gas environment. Many efforts have been made towards the suitable environments which can successfully support embryo development in vitro. For a rapid growth and differentiation, embryo requires energy by utilizing ATP, NADPH with oxygen molecules. These energy substrates are produced from the electron transport chain in the mitochondria. In addition to energy production, reactive oxygen species (ROS) are also generated as by-product of such energy production system. ROS production is sensitively controlled by the balance of oxidizing and reducing status and affected by several antioxidant enzymes such as superoxide dismutase (SOD), Catalase, glutathione peroxidase (GPx) or low molecular weight thiols such as glutathione (GSH). Imbalance of oxidation and reduction causes production of excess ROS, which causes the developmental arrest, physical DNA damage, apoptosis induction or lipid peroxidation. Environmental oxygen condition during embryo culture also highly affects embryo development as well as intracellular redox balance. Several studies have revealed that regulation of intra- and extra- cellular reducing environment by reducing excess ROS by using antioxidants, reducing oxygen concentration are effective for improving embryo development. Also, recent studies have demonstrated the difference in gene expression affected by oxidative stress. This review briefly summarizes the effects of ROS and the role of redox balance on preimplantation embryos for improving the efficiency of in vitro production of mammalian embryos.     

Keap1-Nrf2/ARE信号通路及其在畜禽抗氧化中的研究进展

正常生理状态下,动物体内自由基的产生和清除处于稳定的动态平衡,但发生氧化应激时,体内自由基产生的量超过自身清除能力,引起氧化系统和抗氧化系统的失衡,造成氧化损伤。而Keap1-Nrf2/ARE信号通路的激活在预防氧化应激引起的细胞和组织损伤、维持氧化还原平衡和蛋白质稳态以及调节炎症方面具有关键作用。Keap1是Nrf2的胞浆抑制蛋白,在正常生理状态下,Nrf2与Keap1结合而发生泛素化和蛋白酶体降解,使细胞核内Nrf2的含量维持在一个相对较低的水平。在氧化应激条件下,Keap1对Nrf2的泛素化和降解的能力减弱,细胞核中Nrf2积聚,Nrf2与抗氧化反应元件（ARE）结合后启动下游一系列保护性基因的表达,使机体从氧化应激状态恢复到正常的生理状态。氧化应激参与多种病理生理变化,对畜禽的生产性能、生长发育、繁殖性能、肉品质等有负面影响,Keap1-Nrf2/ARE信号通路是细胞内最重要的抗氧化应激通路之一,对动物的健康保护极其重要。作者总结了Keap1-Nrf2/ARE信号通路的基本结构和活化机制及其在畜禽抗氧化中的研究进展,阐述了其在提高畜禽的抗氧化、抗炎能力和在肉品质中的重要作用,以期为缓解当前畜禽业中严重的氧化应激和炎症提供理论依据。     

围产期奶牛氧化应激、抗氧化防御系统及其与机体炎症反应的关系

氧化应激诱导机体自由基的产生是有氧代谢的一个组成部分。活性氧(reactiveoxygenspecies,ROS)是机体正常代谢过程和某些白细胞群体在疾病防御过程中产生的。越来越多的研究表明,机体组织和细胞产生的氧化损伤会直接或间接诱导许多疾病的发生,进而影响动物健康和福利。高产奶牛的生产性能在一定程度上可通过补充抗氧化剂来优化。概述了氧化应激的研究进展,综述了围产期奶牛氧化应激、抗氧化防御系统及其与炎症反应的关系,以期为进一步揭示抗氧化剂预防免疫功能障碍和宿主组织氧化损伤的分子机理,避免围产期奶牛发生由氧化应激诱导的代谢病和临床型疾病提供新思路。