双歧杆菌对小鼠急性实验性结肠炎作用的研究

Effect of bifidobactria on dextran sulphate sodium-induced acute ulcerative colitis in mice

目的研究双歧杆菌在葡聚糖硫酸钠（DSS）诱导的急性溃疡性结肠炎小鼠模型中的作用。方法将80只BALB／C小鼠均分为8组，每组10只。除正常对照组、单纯0501菌株组、单纯c122菌株组外，其他5组动物均给予5％DSS造模7d。在造模开始前2d，阴性对照组用0．9％氯化钠液灌肠、阳性对照组用柳氮磺胺吡啶（SASP）20mg／ml灌肠、DSS＋0501菌株组用1×10^9CFU／ml0501菌液灌肠、DSS＋cl22菌株组用1×10^9CFU／ml cl22液菌灌肠。9d后处死动物取结肠标本，行H—E染色．观察镜下结肠病理变化，并用免疫组化染色、RT-PCR技术分析结肠黏膜中自细胞介素（IL）-10mRNA及蛋白表达。结果DSS造模过程中给予双歧杆菌灌肠小鼠（0501菌株组和c122菌株组）的结肠炎性反应程度较模型组加重，结肠黏膜IL-10表达减少。而单纯给予双歧杆菌灌肠小鼠（单纯0501菌株组和单纯c122菌株组）未见结肠炎表现。结论双歧杆菌的某些菌株在结肠黏膜屏障功能受损情况下，可加重溃疡性结肠炎小鼠的结肠黏膜损伤。

Objective To investigate the effect of bifidobacteria on dextran sulphate sodium（DSS）- induced acute ulcerative colitis in mice. Methods Thirty BALB/C mice were randomly divided into normal control group （n = 10） , 0501 strain group （n = 10） and cl22 strain group （n = 10）. Fifty BALB/ C mice received 5% dextran sulphate sodium（DSS） for 7 days to induce ulcerative colitis. The mice were then divided to model group, negative control group（perfused with 0.9 NaCl solution ）, positive control group（perfused with SASP of 20 mg/ml）, DSS ＋ 0501 strain group（perfused with 1 ×10^9CFU/ml bifidobacteria 0501 strain solution） and DSS ＋ cl22 strain group （perfused with 1×10^9CFU/ml bifidobacteria cl22 strain solution）. All mice were sacrificed 9 days later. The colon specimens were measure by histochemical staining with H-E. The expressions of interleukin-10 （IL-10） and its protein were detected by RT-PCR and immunohistochemistry respectively. Results The degree of colon inflammation in mice both in DSS＋ 0501 strain and DSS＋cl22 strain groups were aggravated and expressions of IL-10 mRNA and protein were reduced compared to model group. No colon inflammation was found in 0501 strain and cl22 strain groups. Conclusion Some strain of bifidobacteria may aggravate colon inflammation in mice when mucosal barrier is destroyed.