共查询到19条相似文献，搜索用时 203 毫秒
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紧密连接是肠上皮细胞间的主要连接方式,参与维持上皮细胞极性与调节肠屏障的通透性。闭锁蛋白(OCLN)是紧密连接相关蛋白中最具代表性的蛋白之一,是形成紧密连接的基础结构。OCLN的功能主要包括栅栏功能和细胞旁屏障功能,研究发现其表达量降低时可引起肠黏膜屏障功能受损,后者是多种消化道疾病发生发展的一个重要过程。益生菌被认为是抗生素的重要替代物之一,其作用于宿主可产生多种有益作用。大量研究表明给予患者或者为疾病模型动物提供益生菌可有效改善肠黏膜屏障功能。本文就益生菌对肠道OCLN蛋白表达调控机制的研究作一综述,以期为OCLN相关研究和疾病的治疗策略提供理论参考。 相似文献
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肉鸡肠道疾病严重影响着养鸡业的发展,利用益生菌防治肉鸡的肠道疾病已成为当今的研究热点。本文综述了益生菌的特点、肠黏膜免疫屏障、益生菌对肉鸡肠黏膜免疫屏障的作用(调节肠道内微生物的平衡、预防和治疗肠道炎症、增强肠道的免疫屏障),旨在阐明益生菌在肉鸡肠黏膜免疫屏障中的研究进展,为规模化养殖场合理使用益生菌提供理论依据。 相似文献
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肠道免疫屏障功能损伤的研究进展 总被引：6，自引：0，他引：6
肠黏膜免疫屏障作为肠屏障中的第一道防线,有效地保护肠黏膜的完整性,使其不受有害病原体的感染。但在肠黏膜缺血、缺氧、肠道细菌移位、肠内营养障碍、细胞凋亡等状态下,肠黏膜免疫屏障将出现一系列生理和病理变化,导致肠黏膜萎缩和通透性增大。为此,文章从几种损伤机制的角度,对造成肠道免疫屏障损伤的因素及其作用机理作一综述。 相似文献
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肠道不仅是消化吸收的重要场所,也是生物体最大的免疫器官.肠道黏膜面积庞大,它的结构和功能构成了强大的黏膜免疫系统,加之在肠道中生存着大量的微生物菌群,致使外源细菌和病毒很难突破这道防线而对生物体产生危害,所以肠黏膜屏障结构的完整性对机体健康至关重要.肠内细菌移位、菌群紊乱和失调、肠黏膜屏障功能遭到破坏及局部免疫功能下降等极易引发肠源性感染.益生菌能降低肠道pH、减少细菌移位、阻止细菌黏附、防止肠黏膜屏障功能的破坏及增强局部免疫功能,预防和治疗肠源性感染.可见,肠内益生菌所形成的肠黏膜生物屏障在防止致病菌和内毒素经肠道入侵中发挥着重要的作用.现将其如何发挥屏障作用并与肠黏膜机械和免疫屏障协同配合进行探讨. 相似文献
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益生菌是可添加在饲料中对动物健康产生很多益处的活微生物,其在维持胃肠道微生物平衡、免疫调节和病原体防御中起关键作用,某些特定的益生菌菌株对加强肠上皮的完整性和调节一些免疫组分也显示出一定程度的潜力。有关益生菌的作用机制是当前研究的热点,其中,在益生菌调节肠道介导的防御反应的所有可能途径中,肠屏障功能、先天和适应性黏膜免疫反应及信号传导途径被认为在针对病原菌的肠防御反应中起重要作用。作者主要针对益生菌如何与肠道内的杯状细胞黏蛋白、三叶因子（trefoil factors,tffs）、防御素、Toll样受体（Toll-like receptors,TLRs）、分泌型免疫球蛋白A（secretory immunoglobulin A,sIgA）、热休克蛋白（heat shock proteins,HSPs）和P-糖蛋白（P-glycoprotein,P-gp）相互作用而起到调节肠道先天防御反应的作用进行了概述,以期为今后研究益生菌对肠道健康及对感染病原体的肠道如何起到有益作用奠定基础。 相似文献
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选用12头(21±1)d断奶仔猪,随机分为2个处理,研究脂多糖(LPS)刺激对肠黏膜免疫屏障功能的影响。禁食12h后,LPS组仔猪腹膜注射100μg/kgBW LPS,对照组注射等量的生理盐水。48h后,屠宰仔猪,打开腹腔,取小肠组织样品,测定小肠上皮间淋巴细胞、杯状细胞、肥大细胞数、肠集合淋巴结增殖、凋亡细胞数。结果表明:LPS刺激显著降低十二指肠、回肠上皮间淋巴细胞数(P<0.01),极显著增加小肠各段肥大细胞数(P<0.01);LPS刺激显著增加回肠集合淋巴结凋亡细胞数(P<0.05),但对增殖细胞数没有影响(P>0.05);LPS刺激可增加仔猪小肠杯状细胞数,但两处理组间差异不显著(P>0.05)。这些结果显示,LPS应激可导致肠黏膜免疫屏障功能改变,进而加重机体出现急性感染症状。 相似文献
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WAN Hua-yun HU Jun-yi WANG Zi-xu CHEN Yao-xing CAO Jing DONG Yan-jun MA Bao-chen DONG Yu-lan 《中国畜牧兽医》2017,44(12):3642-3649
Intestinal epithelial cells (IECs) are the first line of defense against pathogenic microorganisms of animal organism, which are important component of mucosal mechanical barrier, immune barrier and chemical barrier, they have absorption and barrier double function. In the intestine, there are many kinds of microorganisms. According to its relationship with the host, it is divided into three types of commensal bacteria, conditional pathogenic bacteria and pathogenic bacteria, it plays an important role in the construction of intestinal barrier. Firstly, IECs identify the intestinal microbes by direct or indirect ways, and distinguish their own and non-self, it is immune tolerance to their own substances (such as, commensal bacteria), and produce specific immune response to non-self-substances (pathogenic bacteria). Both of IECs and intestinal commensal bacteria together against pathogens maintain intestinal health. When the pathogenic microorganisms invade the intestine, IECs defense pathogenic microorganisms mainly through extracellular secretions and cell surface mucus layer, and the former largely include mucin, antibacterial molecular and antimicrobial immunoglobulin. The intestinal symbiotic bacteria can resist the pathogenic microorganisms and maintain the normal intestinal mucosal barrier function through the competitive identification sites, the secretion of antimicrobial substances, the increase of mucus secretion, the induction of IECs renewal, proliferation and repair. In the process of resisting invasion of gut microbes, pathogenic microorganisms through their own movement, secretion of toxins and enzymes to destroy the intestinal epithelial barrier, and directly contact with IECs to damage them. So the interaction between IECs and intestinal bacteria maintain the intestinal homeostasis. In this paper, a review is made of the IECs and intestinal microbial structure and functional adaptations, and hope to elaborate the mechanism of intestinal microbial-epithelial cell barrier interaction. 相似文献
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肠道上皮细胞（intestinal epithelial cells,IECs）是动物机体抵御病原微生物的第一道防线,是黏膜机械屏障、免疫屏障和化学屏障的重要组成部分,具有吸收和屏障双层功能。肠道中微生物数量庞大、种类繁多,根据其与宿主的关系,主要分为共生菌、条件致病菌和病原菌3类,在肠道屏障的构建中发挥重要作用。IECs首先通过直接或间接方式对肠道微生物进行识别,区别自身与非自身,对自身物质（即共生菌）免疫耐受,对非自身物质（即病原菌）产生特异性免疫反应。IECs与肠道共生菌共同抵御肠道病原微生物,维持肠道健康,病原微生物侵入肠道,IECs主要通过胞外分泌物和细胞表面黏液层双重屏障发挥作用,其中胞外分泌物主要包括黏蛋白、抗菌分子和抗微生物免疫球蛋白。肠道共生菌可以通过竞争识别位点,分泌抗菌物质,增加黏液分泌,诱导IECs更新、增殖和修复等方式抵御病原微生物,维护正常的肠黏膜屏障功能。在IECs抵御肠道病原微生物入侵过程中,病原微生物通过自身运动、分泌毒素和酶等破坏肠上皮屏障,直接接触IECs,对其进行损伤。因此IECs和肠道菌群间相互作用,共同维持肠道内环境稳态。作者就IECs和肠道微生物结构、功能的适应性变化作一综述,以期阐述肠道微生物-上皮细胞屏障互作的机制。 相似文献
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益生菌在健康硬骨鱼肠道中不仅起到抑制致病微生物的作用,而且更重要的是,益生菌能够刺激和增强肠道黏膜免疫系统,在肠道免疫中起重要作用。近年来,硬骨鱼黏膜免疫因其多样性及其不明确的定义,已成为热门的研究课题。硬骨鱼与水生环境直接接触,使肠道黏膜表面易受各种病原体的侵袭。免疫调节是硬骨鱼中有效的预防性措施,而益生菌能够提高肠道黏膜表面固有的免疫活性细胞和因子,对病原体起颉颃作用。益生菌主要通过口服方式进入鱼体,而肠道作为其主要靶器官,对鱼体产生特异性免疫应答。因此,关于益生菌影响肠道黏膜免疫系统的研究值得关注。相比于哺乳动物,硬骨鱼具有更加弥散的肠淋巴系统。局部免疫应答所必需的免疫细胞大量存在于肠道黏膜中,并且可以在免疫后的鱼体肠道中监测到局部免疫应答。文章综述了近年来硬骨鱼肠道黏膜免疫系统以及益生菌对硬骨鱼肠道黏膜免疫的影响,并对鱼类益生菌的进一步研究进行了展望,以期为后续研究益生菌与硬骨鱼之间相互作用提供参考。 相似文献
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ZHANG Man JIN Xin TIAN Qiao-zhen LIU Jiao WANG Yun-he ZHANG Zhao-yi YANG Yin-feng 《中国畜牧兽医》2017,44(12):3656-3662
Probiotics are a kind of living microorganism which can be administered in feed and confer numerous health benefits to animals. Probiotics play a key role in maintaining the microbial balance of gastrointestinal, immunomodulation and pathogen defense, specific probiotics show certain degree of potential to reinforce the integrity of intestinal epithelium and regulate some immune components. The mechanism of probiotic action is an area of interest. Among all possible routes of modulation by probiotics of intestinal mediated defense responses, modulations of intestinal barrier function, innate and adaptive mucosal immune responses as well as signaling pathways are considered to play an important role in the intestinal defense responses against pathogenic bacteria. This review summarizes how probiotic bacteria interact with goblet cell-derived mucins, trefoil factors (TFFs),defensins, Toll-like receptors (TLRs), secretory immunoglobulin A (sIgA), heat shock proteins (HSPs) and P-glycoproteins (P-gp) in the gut to regulate the intestinal innate defense responses,which is regarded as the scientific basis for the future detailed study of benefits of probiotics towards the health of intestine and also dietary intervention against intestinal exposure to pathogens. 相似文献
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Enteric bacteria: Friend or foe? 总被引：2，自引：0，他引：2
The normal gastrointestinal tract contains an enormous number of aerobic and anaerobic bacteria which normally enjoy a symbiotic relationship with the host but can have adverse effects with local and systemic consequences. The small intestine constitutes a zone of transition between the sparsely populated stomach and the luxuriant bacterial flora of the colon. Regulation of the intestinal flora depends on complex interactions between many factors including secretion of gastric acid, intestinal motility, biliary and pancreatic secretions, local immunity, the surface glycocalyx and mucus layer, and diet. Microbial interactions are also important, and can involve alterations in redox potential, substrate depletion and production of substances such as bacteri-ocins that inhibit bacterial growth. The beneficial effect of the normal enteric flora include the competitive exclusion of potentially pathogenic organisms, and the production of nutrients such as short-chain fatty acids (which represent an important energy source for the colonic mucosa) and vitamins. Detrimental effects of the enteric flora include competition for calories and essential nutrients, particularly by bacteria located in the small intestine, and a capacity to damage the mucosa, in some circumstances causing or contributing to inflammatory bowel disease. These problems can be accentuated by interference with the physiological regulation of intraluminal bacteria allowing overgrowth by a normal resident, or colonisation by transient pathogens. The pathophysiological consequences may involve direct damage to the intestinal mucosa, and bacterial metabolism of intraluminal constituents, for example forming deconjugated bile acids and hydroxylated fatty acids which stimulate fluid secretion. Additional problems arise if there is interference with the mucosal barrier since this can result in increased passage of bacteria and bacterial products stimulating mucosal inflammation, while bacterial translocation can result in bacteraemia and septicaeniia. Problems associated with bacterial pathogens are illustrated by the properties of the spectrum of pathogenic Escherichia coli, some of which facilitate long-term colonisation by adherence to the surface or invasion of enterocytes. 相似文献
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与畜禽等动物相比,鱼类消化系统不健全,消化酶活性低,而植物性原料中常含有抗营养因子和毒性成分等,易导致肠道损伤及肠炎等疾病。丁酸等短链脂肪酸可显著改善鱼类生长性能,增强鱼体健康及抗氧化和抗应激能力。因丁酸气味不佳,影响动物适口性,丁酸钠作为丁酸的替代物,呈固态且不易挥发,易于添加使用。丁酸钠可促进肠道上皮细胞发育,改善肠道形态结构,保持肠道黏膜屏障完整,对损伤的肠道黏膜加以修复,刺激上皮细胞内mRNA和蛋白质合成,加速肠上皮细胞增殖,增加绒毛高度,促进消化吸收。丁酸钠能破坏有害菌DNA结构,蛋白质不能合成,使有害菌不能进行正常分裂,抑制肠道有害菌的生长繁殖,促进有益菌群的增殖,维持肠道菌群平衡,菌群多样性显著提高。丁酸钠可通过刺激消化酶的分泌来改善鱼类消化,降低劣质蛋白原料对肠道损伤,抑制鱼肠道细胞凋亡,减少肠道炎症发生,显著改善鱼类肠道屏障的功能。丁酸钠还可用作生长促进剂及免疫刺激剂,在低鱼粉饲料中使用可降低饲料成本,促进鱼类生长发育。因此,丁酸钠是绿色安全可替代抗生素的添加剂,同时植物蛋白适当替代鱼粉可提高经济效益。作者就丁酸钠对肠道消化吸收功能的影响进行重点阐述,以期为鱼类等水产养殖业使用丁酸钠提供科学参考。 相似文献
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肠道不仅仅是机体消化、吸收营养物质的主要场所,也是机体的一道防御屏障。肠道黏膜屏障包括黏膜生物屏障、机械屏障、化学屏障和免疫屏障,不论是哪一种肠道黏膜屏障受到损伤,都会导致机体不同程度的伤害,与一些疾病的发生密切相关。本文就肠道黏膜屏障机能及其调控研究进展进行综述,为进一步认识肠道黏膜屏障及治疗由其损伤引起的疾病提供参考和帮助。 相似文献
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益生菌对肠道黏膜免疫影响的研究进展 总被引：1，自引：0，他引：1
一些选择性益生菌株具有抑制肠道疾病炎性因子产生、稳定菌群、改善肠道黏膜免疫系统的功能。结合炎症性肠炎(inflammatory bowel disease,IBD),介绍某些选择性益生菌(probiotics)通过调节炎性细胞因子1β-白介素、γ-干扰素的表达,改善肠道黏膜炎症,控制疾病的进一步恶化。作者将从肠道黏膜的重要性,益生菌与Toll样受体、核转录因子(NF-κB)的关系,以及益生菌对肠道黏膜免疫影响等方面进行论述,进而探讨其作用机制,为进一步研究益生菌调节宿主肠道黏膜免疫提供新的思路。 相似文献
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动物肠道存在复杂的微生物群落,适宜的微环境有利于多种肠道微生物的定植生长。肠道健康是保证动物机体健康的基础,也是当前国内外学者所关注的热点问题。益生菌是对肠道健康有益的微生物,在改善动物肠道健康领域具有极大的潜力。益生菌对病原微生物侵袭有一定的抑制作用,对部分病毒也具有一定的预防及清除作用,但不同菌株作用效果存在较大差异。作者首先将益生菌对肠道健康的保护概括为益生菌抑制病原菌入侵和定植、改善肠道屏障功能、维持肠道健康菌群、提高机体免疫力4种方式,并探讨了不同菌株的作用方式;其次简述了益生菌抗肠道病毒的作用机制,其中,益生菌通过间接方式调节机体免疫是其抗病毒的主要方式;最后讨论了近年来益生菌在轮状病毒、流行性腹泻病毒和传染性胃肠炎病毒中应用的研究进展,并对益生菌的发展前景进行了展望,以期为益生菌在改善动物肠道健康的研究及产品的开发方面提供一定的参考依据。 相似文献