In vitro and in vivo effects of the probiotic Escherichia coli strain M-17:: immunomodulation and attenuation of murine colitis
In vitro and in vivo effects of the probiotic Escherichia coli strain M-17:: immunomodulation and attenuation of murine colitis
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DOI：
10.1017/s0007114508930373
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发表时间：
2008-09-01
影响因子：
3.6
通讯作者：
Koltun, Walter A.
中科院分区：
文献类型：
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作者：
Fitzpatrick, Leo R.;Small, Jeffrey;Koltun, Walter A.
我们研究了益生菌大肠杆菌M-17(EC-M17)在体外和体内对葡聚糖硫酸钠(DSS)诱导的小鼠结肠炎中核因子-kappa B信号、细胞因子分泌和疗效的影响。用肿瘤坏死因子-α(100 ng/ml)刺激的核因子-kappa B荧光素酶报告细胞系检测核因子-kappa B信号转导。用暴露于脂多糖(5mU g/ml)的原始264.7巨噬细胞株检测p65核结合和细胞因子分泌(肿瘤坏死因子-α、白介素1-β和白介素6)。给小鼠注射赋形剂、EC-M17、甲硝唑或EC-M17与甲硝唑合用13d。在最后6d，还给小鼠注射2%DSS。评估指标包括疾病活动指数(DAI)、组织学、髓过氧化物酶和核因子-kappaBp65。EC-M17呈剂量依赖性抑制肿瘤坏死因子-α诱导的核因子-kappaB信号转导。EC-M17在5×109个集落形成单位/ml时，对NF-kappaB的抑制率为95%。在1×10(8)个集落形成单位/毫升的浓度下，脂多糖对RAW 264.7巨噬细胞的核p65结合有显著的抑制作用(78%；P<0.05)。EC-M17对脂多糖诱导的肿瘤坏死因子-α、IL-1β和IL-6的分泌也有90%的抑制作用。在DSS诱导的结肠炎小鼠中，EC-M17、甲硝唑和EC-M17联合甲硝唑显著降低DAI和结肠组织学评分。EC-M17和甲硝唑均能降低结肠IL-12、IL-6、IL-1β和干扰素-γ水平。联合应用EC-M17和甲硝唑比单独使用任何一种方法都能显著降低细胞因子，并且联合治疗显著降低IL-1β(与EC-M17相比P<；0.05)和结肠组织学评分与甲硝唑相比。单独和与甲硝唑联合使用，EC-M17改善了小鼠结肠炎，可能是由于抑制了核因子-kappa B信号的作用。
We examined the in vitro and in vivo effects of a probiotic, Escherichia coli strain M-17 (EC-M17), on NF-kappa B signalling, cytokine secretion and efficacy in dextran sulfate sodium (DSS)-induced murine colitis. NF-kappa B signalling was assessed using an NF-kappa B luciferase reporter cell line that was stimulated with TNF-alpha (100 ng/ml). p65 Nuclear binding and cytokine secretion (TNF-alpha, IL-1 beta and IL-6) were evaluated using a RAW 264.7 macrophage cell line that was exposed to lipopolysaccharide (LPS; 5 mu g/ml). Mice were administered vehicle, EC-M17, metronidazole, or EC-M17 plus metronidazole for 13 d. During the final 6 d, mice also received 2% DSS. Parameters evaluated included disease activity index (DAI), histology, myeloperoxidase and NF-kappa B p65. EC-M17 dose dependently inhibited TNF-alpha-induced NF-kappa B signalling. At 5 X 109 colony-forming units/ml, EC-M17 inhibited NF-kappa B by > 95%. LPS-induced nuclear p65 binding was significantly inhibited (78%; P < 0.05) in RAW 264.7 macrophages at 1 x 10(8) colony-forming units/ml. EC-M17 also inhibited (by > 90%) the LPS-induced secretion of TNF-alpha, IL-1 beta and IL-6. In mice with DSS-induced colitis, EC-M17, metronidazole, and EC-M17 plus metronidazole significantly reduced DAI and colonic histology scores. Both EC-M17 and metronidazole reduced colonic IL-12, IL-6, IL-1 beta and interferon-gamma. The combination of EC-M17 plus metronidazole resulted in more substantial cytokine reductions than were found with either treatment alone, and combination therapy significantly (P < 0.05 in both cases) reduced IL-1 beta compared with EC-M17 and colonic histology scores compared with metronidazole. Alone, and in combination with metronidazole, EC-M17 improved murine colitis, probably due to an inhibitory effect on NF-kappa B signalling.