| Objective:To screen the appropriate dose of lactobacillus acidophilus that could effectively treat the mice with experimental murine colitis, and evaluate the treatment efficacy.Methods:Colitis was induced by oral administration of 2.5% dextran sodium sulfate(DSS). BALB/c mice received different dose (low-, medium-and high-dose) of lactobacillus acidophilus orally for 7 days. The body weight and the character of feces as well as occult blood were observed daily. Histological damage was assessed in colonic tissue. On the 7th day, all mice were sacrificed. Colons were removed, washed in normal saline, samples for histology were then cut longitudinally and fixed in 10% formalin, dehydrated, and embedded in paraffin. Samples for cytokine mRNA and protein measurements were frozen in liquid nitrogen and stored at-70℃until needed.Results:Compared with the normal group, the levels of the disease activity index and Histopathology scores were increased (7.81±1.02VS0, 5.80±2.94VS0,P<0.05).Lactobacillus acidophillus and mesalamine allev-iated the general situation and the weight loss obviously and dramatically reduced the disease activity index and Histopathology scores(6.20±2.64, 5.00±1.21,5.7±2.63,5.81±1.32 VS7.81±1.02;4.25±2.05,2.56±1.81, 2.20±1.12,3.10±2.60 VS 5.80±2.94, P<0.05).Conclusion:L. acidophilus could effectively treat mice with experimental colitis. The effect was dose dependent. The high dose group (1*108CFU/mL) had a better effect. Objective:The aim of this study was to compare the bacterial composition and to identify differences in the mucosa associated intestinal microflora of mice with active colitis and health controls with the cloning experiments, SSCP fingerprinting and real time PCR in biopsy samples. Bacterial culture technique was also used to investigate the changes of common cultured flora such as lactobacilli, bifidobacterium,enterococcus, and enterobacter after intervention with different dose of L. acidophilus.Methods:The composition of the common cultured intestinal microflora in mucosal samples was investigated using classical bacterial culture. Single strand conformation polymorphism (SSCP) analysis using universal primers was used to determine microbial diversity in mucosal samples.Results:Staphylococcus aureus (6.13±0.47) and the total count of aerobian (6.80±1.60, P<0.05) were increased significantly in acute experimental colitis mice compared with controls.While Bifidoba-cterium(5.38±0.94, P<0.05) and Lactobacillus (3.69±1.48, P<0.05) were reduced sharply.Afer supplementary with L. acidophilus, the structure of the flora changed. The number of Bifidobacterium and Lactobacillus increased while Staphylococcus aureus decreased.the total count of aerobian and the total count of bacteroid were similar.The mean numbers of bands are shown. Diversity of the normal controls(10.67±2.51)was significantly higher compared with the disease groups(6.60±2.48). Considering not only number of bands but also their intensity, analysis of the most obviously different bands indicated that the main difference between the two groups was the uncultured bacteria.Conclusion:Dysbacteria was found by the analysis of fecal flora in acute experimental colitis.The number of the Staphylococcus aureus and the total count of aerobian were increased while Bifidobacterium and Lactobacillus were reduced.Diversity of the microflora in experimental colitis mice was reduced in comparison with controls.The uncultured bacteria was the main difference. Objective:To research the potential mechanism for probiotics therapy and the optimizing effect on dextran sulphate sodium (DSS)-induced acute experimental colitis.Inhibiting or relieving the infiltration of inflammantory cells, maintaining the balance between the proinflammatory and anti-inflam-matory cytokines and improving the histological damage of colonic mucosa may be the partial mechanism of probiotics on treating UC.Methods:We analysed the Th1/Th2 cytokine profile and the transcription factor in the IL-12/STAT4/T-bet,IFN-γ/STAT1/T-bet,IL-4/GATA3 signaling in the mucosa of experimental colitis mice. IL-12,STAT4,T-bet,IFN-γ,STAT1,IL-4,GATA3 expression in colonic mucosa were measured by reverse transcription polymerase chain reaction(RT-PCR). At the same time, T-bet expression was measured by Western blot and IHC.Result:Expressions of cytokines:After treatment, the expressions of the Thl cytokine profile (IL-12 and IFN-γ) were decreased while the expressions of the Th2 cytokine profile (IL-4) was increased obviously in the Lactobacillus acidophilus low dose group, Lactobacillus acidophilus dose group,Lactobacillus acidophilus high dose group and mesalazine group compared with the model group(IL-12:0.36±0.08, 0.37±0.02,0.35±0.01,0.35±0.14VS0.52±0.03; IFN-γ:0.78±0.08, 0.68±0.11,0.62±0.13,0.76±0.03VS0.76±0.03;IL-4:0.59±0.03,0.66±0.22, 0.75±0.07,0.64±0.22VS0.58±0.12).Expressions of the transcription factor:After treatment, the levels of the transcription factorSTAT4, STAT1, T-bet were decreased in the Lactobacillus acidophilus low dose group, Lactobacillus acidophilus median dose group,Lactobacillus acidophilus high dose group and mesalazine group(0.40±0.06,0.37±0.01,0.32±0.13,0.36±0.22 VS0.54±0.11; 0.59±0.12,0.55±0.01,0.54±0.13,0.45±0.15 VS0.76±0.05; 0.28±0.12,0.27±0.03,0.23±0.04, VS0.41±0.01, P<0.05; 0.36±0.02 VS0.41±0.01, P>0.05),while the level of GATA3 was increased (0.78±0.25, 0.75±0.23,0.82±0.16,0.81±0.09 VS 0.60±0.23,P<0.05).Compared with the model group, After treatment,the expression of T-bet in the level of protein and Immunohistochemistry were decreased in the Lactobacillus acidophilus low dose group, Lactobacillus acidophilus median dose group,Lactobacillus acidophilus high dose group and mesalazine group (027±0.04,,0.23±0.02,0.18±0.04,0.27±0.11 VS0.30±0.04; 0.263±0.045,0.234±0.015, 0.114±0.025,0.252±0.024 VS 0.322±0.064 P<0.05),and among these treatment groups, the Lactobacillus acidophilus high dose group has the optimal effcacy (0.18±0.04VS0.30±0.04,0.114±0.025 VS 0.322±0.064, P<0.05).Conclusion:Lactobacillus acidophilus could ameliorate the infla-mmatory in the colon.To inhibit the signaling pathways IFN-γ/STAT1 and IL12/STAT4 and activate the pathway IL-4/GATA3 may be the possible mechanism. |
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