| Background and ObjectiveProbiotics of human intestinal play an important role in maintaining the health of the host gastrointestinal tract. Zairian M, et al indicated that probiotics can prevent chronic stress induced intestinal abnormalities and, thereby, exert beneficial effects in the intestinal tract. There has substantial research focusing on modulation of the intestinal microbiota and host inflammatory responses by probiotics. Probiotics are defined as non-pathogenic live microorganisms that can have health benefits for the host. Such microorganisms have been used extensively for both the prevention and treatment of various inflammatory and infectious intestinal disorders, including IBD, IBS. Therefore, attention has been focused on probiotics therapeutics. Smecta (montmorillonite powder) is a mucosal barrier agent, used clinically to treat diarrhea.Despite large amount of data shows probiotics can regulate intestinal immunity, block pathogen adhesion to improve mucosal barrier function, but there were few studies related on the probiotics treating stress-related illness. Using Bifidobacterium longum to regulate intestinal function under psychological stress has not been reported yet. In this study, we intend to use water avoidance stress (WAS) to simulate environment and psychological pressure. The aim of this study is to determine the influence of chronic psychological stress on intestinal microflora and corticotropin-releasing factor (CRF) on rats and the protective effects of Bifidobacterium longum and Smecta.MethodsFifty female Sprague Dawley rats were randomly and equally divided into five groups:normal group, stress group, Bifidobacterium group, Smecta group, Bifidobacterium plus Smecta group. All these groups were subjected to either water avoidance stress (WAS) or normal condition for tow hours per day for 7 consecutive days.1. The intestinal permeability in vivo was evaluated by measuring urinary sucralose and other sugar probes including lactulose and mannitol using capillary column gas chromatography (CCGC) method;2. Some representative genera of gut flora in their feces were detected by using selected culture media plate counting method;3. The mesenteric lymph nodes (MLN) were cultured to determine the bacterial translocation;4. The small intestine between ligament of Treitz and ileocecal valve was cuted down for biopsy to observe mucosal injury;5. The contents of CRF and adrenocorticotrophic hormone (ACTH) of their blood sera were determined by enzyme-linked immunoad sorbent assay (ELISA).Results1. Compared with the normal group, the amount of Escherichia coli in stress group increased significantly (7.078±0.229 vs 7.347±0.277, P<0.05); the 24h's mannitol concentration (4.718%<0.399% vs 5.097%±0.453%, P<0.05) and MLN bacterial translocation of stress group increased significantly (10% vs 40%, P<0.05); the CRF (267.0±32.3 vs 300.8±34.3, pg·mL-1, P<0.05) and ACTH (5.68±0.799 vs 6.79±0.651, pg·mL-1, P<0.05) levels of stress group increased significantly.2. In comparison with the stress group, the amount of Escherichia coli (7.347±0.277 vs 7.044±0.281, P<0.05), bacteroids (9.485±0.306 vs 9.075±0.393, P<0.05) and ACTH level (6.79±0.651 vs 5.92±0.477, pg·mL-1, P<0.05) in Bifidobacterium intervention group decreased significantly; the amount of Escherichia coli (7.347±0.277 vs 7.054±0.302, P<0.05) and MLN of bacterial translocation (40% vs 20%, P<0.05) in Smecta group decreased significantly.3. Compared with Bifidobacterium longum or Smecta used only group, there was little change in Bifidobacterium longum and Smecta group.Conclusions1. The amount of Escherichia coli increased and intestinal microfloradisturbance occurred; MLN bacterial translocation occurred, intestinal permeability increased and the blood sera content of CRF was increased significantly in rats after suffering from chronic psychological stress.2. After beening treated with Bifidobacterium longum and Smecta, The amount of Escher-ichia coli decreased, the CRF and ACTH levels decreased, MLN bacterial translocati-on decreased, Bifidobacterium longum and Smecta could alleviate the gut microflora disturbance caused by the chronic psychological stress and partly restore its intestinal barrier function.3. In treatment of intestinal dysfunction caused by chronic psychological stress, Bifidobacterium longum and Smecta are not in synergies.4. CCGC can be used to determine the intestinal permeability. This method was higher specificity, higher sensitivity and cloud lower the cost of experiment. |
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