产肠毒素大肠杆菌K88诱发BALB/c鼠肠炎模型的建立及评价

Establishment and evaluation of bacterial enteritis model in BALB/c mice induced by enterotoxigenic Escherichia coli K88

为建立BALB/c小鼠感染产肠毒素大肠杆菌(ETEC)K88肠炎模型,本研究分别灌服小鼠浓度为1.0×107cfu/m L、1.0×108cfu/m L和1.0×109 cfu/m L的菌液,连续灌服3 d,对其发病情况和外周血中各细胞因子水平进行检测。结果显示,灌菌后小鼠食欲下降、体重降低,外周血中IL-1α、TNF-α以及髓过氧化物酶(MPO)含量增加,十二指肠病理组织切片显示炎症发生。灌菌期结束后第5 d,小鼠粪便稀软,体重降到最低,所检测的细胞因子含量达到峰值,与对照组差异极显著(p<0.05);十二指肠肠黏膜层与肌层间隙增宽、杯状细胞增多、固有层与黏膜层炎性细胞侵润,炎症变化最为明显。本研究建立了BALB/c小鼠感染ETEC K88肠炎模型,于灌菌期结束后第5 d炎症最为严重。此外,接种不同浓度菌液的小鼠炎性因子数量变化差异不显著(p>0.05)。

To establish the model of bacterial enteritis in BALB/c mice induced by enterotoxigenic Escherichia coli （ETEC） K88, the mice were irrigated with the E.coli at concentrations of 1.0 ×10 7 cfu/mL, 1.0 ×10 8 cfu/mL and 1.0 ×10 9 cfu/mL, respectively. After constant perfusion for three days, the incidence and the level of cytokines in peripheral blood were detected. The results showed that both the appetite and body weight of the mice decreased, but the levels of IL-1α, TNF-α and MPO increased in the mice. In addition, the histopathological change of duodenum indicated that the inflammatory reaction had occurred after perfusion. Five days after perfusion the body weight of the mice declined to the lowest with serious diarrhea, and the levels of peripheral blood cytokinesin the perfused group increased significantly than that in control group （p〈0.05）. The gap between mucosa and muscular became wide and there appeared an increase of goblet cells, and inflammatory cell infiltration between lamina propria and mucosa along with obvious inflammatory change. This study successfully established the mouse enteritis model by perfusion of ETEC K88, and the inflammation was the most serious on the fifth day after perfusion. However, the different concentration of bacteria had little effect on the levels of inflammatory cytokines （p〉0.05）.