低聚乳果糖对断奶应激大鼠肠道紧密连接及屏障功能的影响

发布时间：2018-10-04 20:48

【摘要】：肠道屏障作为机体防御外部致病原的第一道防线具有重要的作用,断奶幼龄动物由于受心理、环境、营养等因素的影响,断奶应激会改变消化道结构和内部微生态环境,进而破坏肠道屏障功能,增加肠道通透性,引起炎症性腹泻,影响断奶幼龄动物正常的生长发育,甚至危及生命。本实验首先研究低聚乳果糖不同剂量对断奶大鼠在不同时间段内的生长性能的影响,随后以脂多糖刺激断奶大鼠模拟断奶幼龄动物生病前的机体环境,研究断奶大鼠在低聚乳果糖预前干预的情况下的血清中生化指标、大便理化性质、肠道内部微环境和形态、肠道通透性、肠道黏膜中细胞因子水平及上皮细胞紧密连接蛋白表达的变化。以期揭示不同剂量低聚乳果糖调控断奶动物肠道紧密连接及屏障功能的机制。同时可为研究低聚乳果糖应用于婴儿食品配方提供科学的参考依据。实验结果表明,在第2周的时间内,低聚乳果糖才对断奶大鼠生长性能发挥了有益作用,表现为体质量有增加的趋势(p0.05),料重比显著下降(p0.05)。脂多糖应激后,相对于阳性断奶大鼠,低聚乳果糖能显著增加血清中IgM水平(p0.05),显著降低血清中ALB(p0.05)、BUN(p0.05)、CK(p0.05)水平；显著降低盲肠食糜中NH3-N水平(p0.05),增加食糜中乙酸和丙酸及大便中丁酸的含量(p0.05)；明显改善大便形状评分(p0.01),显著减少大便次数(p0.05)；显著增加空肠和回肠绒毛高度／隐窝深度比值(p0.05)、结肠黏液层厚度和上皮细胞间杯状细胞数(p0.05)；显著减少肠道通透性(p0.05),抑制血清中DAO活性,调节促炎性和抑炎性细胞因子的平衡,显著增加断奶大鼠结肠黏膜Occludin蛋白表达(p0.05)。综上所述,低聚乳果糖对断奶大鼠生长性能有促进作用。通过抑制肠道黏膜萎缩,改善肠道微环境,增加肠道紧密连接蛋白的表达,降低肠道通透性,保护断奶大鼠肠道屏障功能。
[Abstract]:Intestinal barrier plays an important role as the first line of defense against external pathogenic agents. Weaning young animals are affected by psychological, environmental and nutritional factors, and weaning stress will change the structure of digestive tract and internal microecological environment. Furthermore, the function of intestinal barrier is destroyed, intestinal permeability is increased, inflammatory diarrhea is caused, normal growth and development of weaning young animals are affected, and even life is endangered. The effects of different doses of oligosaccharide on the growth performance of weaned rats at different time periods were studied, and then lipopolysaccharide was used to stimulate weaning rats to simulate the organism environment before weaning young animals became ill. To study the serum biochemical indexes, stool physicochemical properties, intestinal microenvironment and morphology, and intestinal permeability of weaned rats after pre-intervention with oligosaccharide. Changes of cytokine levels and tight junction protein expression in intestinal mucosa. The aim of this study was to reveal the mechanism of regulation of tight intestinal junction and barrier function in weaned animals with different doses of oligosaccharide. At the same time, it can provide scientific reference for studying the application of oligosaccharide in infant food formulation. The results showed that during the second week, fructose-oligosaccharide had a beneficial effect on the growth performance of weaned rats, showing an increasing trend of body mass (p0.05) and a significant decrease in the ratio of feed to weight (p0.05). After lipopolysaccharide stress, fructose oligosaccharides significantly increased the level of IgM in serum and decreased the level of bun (p0.05) and CK (p0.05) in serum compared with positive weaned rats. The content of acetic acid and propionic acid and butyric acid in stool were significantly decreased (p0. 05), the scores of stool shape were improved (p0. 01), the number of defecation was significantly decreased (p0. 05), the content of acetic acid and propionic acid in chylum was increased significantly (p0. 05), and the score of stool shape was significantly improved (p0. 01). The ratio of height of jejunum and ileum villi to crypt depth (p0.05), the thickness of mucus layer of colon and the number of goblet cells between epithelial cells (p0.05) were significantly increased, the intestinal permeability was significantly decreased (p0.05), the activity of DAO in serum was inhibited, and the balance of pro-inflammatory and anti-inflammatory cytokines was regulated. The expression of Occludin protein in colon mucosa of weaned rats was significantly increased (p0.05). In conclusion, fructooligosaccharide can promote the growth performance of weaning rats. Through inhibiting intestinal mucosal atrophy, improving intestinal microenvironment, increasing the expression of intestinal tight junction protein, reducing intestinal permeability and protecting intestinal barrier function of weaning rats.
【学位授予单位】：南昌大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R151

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