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【目的】酸马奶可防治心血管、消化系统、肺结核、糖尿病和腹泻等疾病,尤其马克斯克鲁维酵母Kluyveromyces marxianus对单核细胞增生李斯特菌Listeria monocytogenes有抑菌作用,但对酸马奶提取K.marxianus代谢抗菌复合物抑菌作用的研究报道较少。为此,研究酸马奶提取K.marxianus代谢抗菌复合物对感染致病性大肠杆菌Escherichia coli O_8小鼠免疫机能及其盲肠菌群的影响。【方法】将128只小鼠随机分为4组,空白组、致病对照组、K2组和K8组,致病对照组小鼠连续7 d灌胃无菌PBS,并于第4天注射E.coli O_8;K2组灌胃抗菌复合物K.marxianus p H 2.0,并注射E.coli O_8;K8组灌胃抗菌复合物K.marxianus p H 8.0,并注射E.coli O_8。采用常规HE染色法观察0、4和7 d小鼠小肠病理切片,称重法测定小鼠免疫器官指数,ELISA法测定血清中免疫球蛋白,流式细胞术测定T细胞亚群,平板涂布法测定盲肠菌群。【结果】致病对照组小鼠在实验第4天注菌后出现一系列患病临床症状和小肠组织病理变化。K2组和K8组小鼠整体精神状态好于致病对照组,死亡小鼠数量较少,可一定程度上缓解和改善感染致病性E.coli O_8小鼠的小肠组织病理变化。致病对照组在第7天胸腺指数显著低于空白组(P<0.05)。K2组和K8组在第4天和第7天脾脏指数显著高于空白组(P<0.05)。致病对照组在第7天Ig A显著低于空白组(P<0.05)。K2组在第4天Ig A、Ig G显著高于空白组(P<0.05)。K2组在第7天Ig G和Ig M显著高于空白组(P<0.05)。K8组在第7天Ig M显著高于空白组(P<0.05)。K2组在第4天和第7天CD8+显著低于空白组,CD4+/CD8+显著高于空白组(P<0.05)。K8组在第4天CD8+显著低于空白组(P<0.05)。K8组在第7天CD8+显著低于空白组,CD4+/CD8+显著高于空白组(P<0.05)。致病对照组在第7天盲肠E.coli数量显著高于空白组,双歧杆菌数量显著低于空白组(P<0.05)。K2组在第7天盲肠E.coli数量显著低于空白组,肠球菌数量显著低于空白组,乳酸杆菌数量显著高于空白组(P<0.05)。K8组在第7天盲肠肠球菌数量显著低于空白组,乳酸杆菌数量显著高于空白组(P<0.05)。【结论】酸马奶提取K.marxianus代谢抗菌复合物K2和K8能缓解感染致病性E.coli O_8小鼠临床症状,提高其免疫机能,并影响其盲肠菌群,提高双歧杆菌和乳酸杆菌,降低E.coli和肠球菌的数量。
【Objective】 Yogurt milk can prevent cardiovascular diseases, digestive system, pulmonary tuberculosis, diabetes and diarrhea, especially Kluyveromyces marxianus has antibacterial activity against Listeria monocytogenes, There are few reports on the bacteriostasis of extracting K.marxianus metabolites and antibacterial compounds. Therefore, the study on the effect of kumquat milk extract of K.marxianus on the immune function and the flora of pathogenic Escherichia coli O_8 mice was studied. 【Methods】 128 mice were randomly divided into 4 groups, blank group, pathogenic control group, K2 group and K8 group. The pathogenic control group mice were given sterile PBS for 7 consecutive days and injected with E The group K2 was orally administered K.marxianus p H 2.0 and injected with E.coli O_8; the group K8 was orally administered with K.marxianus p H 8.0 and E.coli O_8. The pathological sections of small intestine of mice were observed at 0, 4 and 7 days by conventional HE staining, the immune organ index of mice was measured by weighing method, the serum immunoglobulin was measured by ELISA, the T cell subsets were determined by flow cytometry, Determination of cecal flora. 【Results】 A series of pathological symptoms and histopathological changes of small intestine occurred in the pathogenic control mice after the fourth day of the experiment. The overall mental status of K2 and K8 mice was better than that of pathogenic control mice, with fewer death mice, which could alleviate and improve the histopathological changes of pathogenic E. coli O_8 mice infected to some extent. The thymus index of the control group on day 7 was significantly lower than that of the blank group on the 7th day (P <0.05). The spleen index of K2 and K8 groups was significantly higher than that of blank group on the 4th and 7th days (P <0.05). On day 7, Ig A in pathogenic control group was significantly lower than that in control group (P <0.05). At day 4, Ig A and Ig G in K2 group were significantly higher than those in blank group (P <0.05). On day 7, Ig G and Ig M in K2 group were significantly higher than those in blank group (P <0.05). IgM in K8 group was significantly higher than that in blank group on the 7th day (P <0.05). On the 4th and 7th day, the level of CD8 + of K2 group was significantly lower than that of the blank group, and the ratio of CD4 + / CD8 + was significantly higher than that of the blank group (P <0.05). On day 4, CD8 + in K8 group was significantly lower than that in blank group (P <0.05). On day 7, CD8 + of K8 group was significantly lower than that of blank group, and CD4 + / CD8 + was significantly higher than that of blank group (P <0.05). The number of caecal E. coli in the control group was significantly higher than that in the blank group on day 7, and the number of bifidobacteria was significantly lower than that in the blank group (P <0.05). The number of caecal E. coli in K2 group was significantly lower than that in blank group on day 7, the number of Enterococcus was significantly lower than that in blank group, and the number of Lactobacillus was significantly higher than that in blank group (P <0.05). The number of Enterococcus faecalis in K8 group was significantly lower than that in blank group on the 7th day, and the number of Lactobacillus was significantly higher than that in the blank group (P <0.05). 【Conclusion】 The extraction of K.marxianus metabolites and antimicrobial compounds K2 and K8 can alleviate the clinical symptoms of infected E. coli O_8 mice, increase their immune function, affect their cecal flora, and increase the levels of bifidobacteria and lactate Bacillus, reduce the number of E. coli and enterococci.