共查询到20条相似文献,搜索用时 78 毫秒
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动物的胃肠道是直接与外部环境接触的部位,时刻暴露于各种外源和内源物质当中。因此,胃肠道中具有功能性上皮屏障,以防止各种物质侵入组织内部。胃肠道微生物在维持胃肠道上皮屏障稳态和强化方面发挥重要作用。胃肠道上皮屏障与微生物相互作用调节宿主胃肠道生长发育、新陈代谢和免疫功能的建立,而宿主胃肠道上皮屏障功能的建立也会影响胃肠道微生物的定殖与分布。本综述总结了胃肠道上皮屏障的结构与功能,以及胃肠道微生物和胃肠道上皮屏障之间的相互作用关系。旨在为胃肠道微生物与胃肠道上皮屏障间关系的研究提供参考。 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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肠道菌群数量大、种类繁多,会对宿主产生各种各样的影响,包括营养代谢、免疫系统调节和抵御感染等,在维持肠道稳态平衡中起着重要作用。肠道上皮细胞是肠道防御系统的关键。肠道上皮是动物机体抵御微生物的第一道屏障,具有吸收和屏障功能,还是宿主与微生物群交流的主动传感器,而这样的功能是肠道菌群与肠上皮各类细胞间相互作用的结果。论文以肠道菌群与肠上皮细胞中的几类典型细胞之间的互作关系展开论述,旨在为如何通过各类细胞发挥的功能来协调肠道菌群的稳定,进而为预防或治疗某些由于肠道菌群失调而导致的疾病提供理论依据。 相似文献
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滥用抗生素会引起动物肠道菌群失调,影响动物免疫。通过对肠道微生物的组成,研究肠道微生物和哺乳动物的免疫系统之间的相互作用,为研究抗生素诱导菌群和免疫稳态失衡打下理论基础。 相似文献
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家禽肠道微生物作为肠道黏膜屏障的重要组成部分在宿主的肠道屏障功能维持和肠道健康稳定中发挥重要作用。益生菌和益生元是调控肠道微生物的有效手段,其中真菌多糖作为天然代谢产物,具有抗氧化、增强免疫等多种生物活性,是一种重要的潜在益生元,其在鸡体内无法直接消化利用,主要通过肠道微生物进行发酵降解,并产生相关代谢产物,真菌多糖与肠道微生物的相互作用会对肠道屏障功能产生积极影响。文章在简要概述家禽肠道微生物的定植和影响因素、家禽肠道黏膜屏障功能及其干预调控手段的基础上,重点阐述了潜在益生元真菌多糖干预家禽肠道微生物对肠道屏障功能的调控作用,为家禽肠道健康调控奠定理论基础,并为真菌多糖产品的开发提供参考。 相似文献
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German AJ Hall EJ Day MJ 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2003,17(1):8-20
Normal individuals maintain tolerance to the endogenous bacterial flora residing within their alimentary tract, a phenomenon mediated by the gastrointestinal lymphoid tissue. Loss of this tolerance is a key factor in the development of chronic intestinal inflammation. Manifestations of such uncontrolled inflammation in humans include inflammatory bowel disease and celiac disease. Dogs may similarly be affected, and although the etiopathogenesis is likely similar, the lesions differ. This review includes discussion of the factors involved in breakdown of mucosal tolerance, the immunologic basis of canine enteropathies, and the use of novel immunotherapies for these diseases. 相似文献
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E F Wolfman 《Veterinary Clinics of North America: Equine Practice》1989,5(2):295-307
Operations for intestinal ischemia are frequently done by veterinarians. In equine surgery those conditions commonly producing ischemia are intussusception, volvulus, bowel obstructions, and incarcerated hernias. In an attempt to predict intraoperative bowel viability after the restoration of circulation, a variety of adjuvant methods have been investigated. There is little question that of the techniques currently available, sodium fluorescein injected intravenously approaches the ideal in predicting nonviability in humans and in most animal models. Furthermore, it is safe, takes little operating time, is inexpensive, and is ubiquitously available; in addition, the only special equipment needed is a long-wave ultraviolet lamp. Reliance on this method would seldom result in nonviable bowel being left in situ. Furthermore, the use of fluorescein would minimize the unnecessary resection of viable intestine and, thereby, minimize the postoperative nutritional problems that may occur, especially in equines. The report of Sullins et al questions the accuracy of the fluorescein technique in predicting viability and nonviability in horses and also raises the question as to whether the prediction of viability, after the restoration of intestinal blood flow, also predicts normal intestinal function. Further investigations will be needed to confirm or refute these observations. 相似文献
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Small intestinal morphology and activity of intestinal peptidases in piglets around weaning 总被引:10,自引:0,他引:10
Hedemann MS Højsgaard S Jensen BB 《Journal of animal physiology and animal nutrition》2003,87(1-2):32-41
The effect of weaning on small intestinal morphology and the activities of three intestinal peptidases was investigated from 3 days prior to weaning to 9 days post-weaning in 64 piglets. Villous height, crypt depth and mitotic counts were determined at three positions along the small intestine. The activities of aminopeptidase N, dipeptidylpeptidase IV and gamma-glutamyl transpeptidase were measured at five positions along the small intestine. The villous height was maximal on the day of weaning. Post-weaning, the villi shortened at the proximal positions of the small intestine and the minimal length was observed on day 3 after weaning. Villous height did not decrease distally in the small intestine. Increased crypt depth was observed from 3-7 days post-weaning at all positions examined. Mitotic counts showed increased proliferative activity in the crypts from the third day post-weaning. Weaning influenced the activity of aminopeptidase N and dipeptidylpeptidase IV. The activities declined until day 3 post-weaning. After that, the activities increased and they had reached pre-weaning values by day 9 post-weaning. Weaning had only minor effect on the activity of gamma-glutamyl transpeptidase. In summary, weaning induced changes in small intestinal morphology and enzyme activity. The changes were maximal on day 3 post-weaning and during the following days, a gradual recovery of the small intestine was observed. 相似文献
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J V Davies 《Veterinary Clinics of North America: Equine Practice》1989,5(2):271-281
Perhaps because of the inherent difficulty in using horses as experimental animals, only a relatively small amount of data is as yet available regarding normal equine gut motility. However, it is clear that the horse is fundamentally similar to other mammalian species studied. The neural and humoral control of gut activity requires much exploration; it is likely that, in the horse, some of this information will be derived during the investigation of the effects of various substances that might have clinical relevance. This is alluded to in the chapter that follows (The Effects of Pharmacological Agents on Gastrointestinal Motility). The clinical applications are likely to remain limited, though some light may be shed upon the derivation of certain disorders. 相似文献
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Canine intestinal carcinoids 总被引:1,自引:0,他引:1
Intestinal carcinoids were diagnosed in three aged dogs. Two of the neoplasms occurred in the rectum and one at the cecocolic junction. Judged by histologic criteria, all three carcinoids were considered to be malignant. Amyloid was present in both rectal tumors. In each tumor the diagnosis was confirmed by the finding of electron-dense intracytoplasmic secretory granules in the neoplastic cells. 相似文献
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D F Smith 《Modern veterinary practice》1984,65(9):705-710
A clear understanding of the surgical anatomy of the bovine intestinal tract is the most important factor in determining the degree of success to be achieved in the surgical management of intestinal disorders in cattle. However, bovine intestinal anatomy can be very difficult to comprehend, especially in cattle with intestinal distention and malposition. The abundance of mesenteric and omental fat and the compact nature of the mesentery make manipulation and exteriorization of many parts of the bowel difficult. Therefore, it is important to accurately identify specific surgical landmarks. A good working knowledge of the relevant surgical anatomy increases the level of confidence in one's surgical abilities and makes one more willing to consider surgical intervention in a cow with suspected GI dysfunction. 相似文献