致病性大肠杆菌诱发腹泻对犊牛早期肠道黏膜通透性及免疫功能的影响

Effect of diarrhea induced by pathogenic Escherichia coli on early intestinal mucosal permeability and immune function in calves

为了研究致病性大肠杆菌O1(E.coli O1)诱发腹泻对犊牛早期肠道黏膜通透性及免疫功能的影响,试验选取48头体况相似的犊牛,将其随机分为试验组和对照组,对照组犊牛未接菌常规哺乳,试验组犊牛在相同饲喂基础上口服100 mL活菌数为2.5×1011 cfu/mL的致病性E.coli O1菌悬液以建立动物腹泻模型,检测犊牛肠道黏膜通透性标记物、血清中免疫因子和免疫球蛋白的水平,试验期为10 d。结果表明:致病性E.coli O1诱发的犊牛腹泻能够明显提高二胺氧化酶(diamine oxidase,DAO)和内毒素(endotoxin,ET)水平(P<0.05或P>0.05);显著提高犊牛肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)、白细胞介素-6(interleukin-6,IL-6)和白细胞介素-1β(IL-1β)水平(P<0.05),降低白细胞介素-10(IL-10)、白细胞介素-4(IL-4)和转化生长因子-β(transforming growth factor-β,TGF-β)水平(P<0.05);显著降低免疫球蛋白A(immunoglobulin A,IgA)和免疫球蛋白M(IgM)水平(P<0.05),免疫球蛋白G(IgG)水平降低但不显著(P>0.05)。说明致病性E.coli O1诱发的犊牛腹泻能够增加犊牛早期肠道黏膜通透性、损伤肠道黏膜屏障和降低免疫功能。

In order to study the effect of diarrhea induced by E.coli O1 on intestinal mucosal permeability and immune function of early calves, 48 calves with similar body condition were randomly divided into test group and control group. The control group was not inoculated and routinely breastfed, on the basis of the same feeding, the test group established an animal diarrhea model by oral administration of 100 mL of a virulent E.coli O1 suspension with a viable count of 2.5×1011 cfu/mL for 10 days. The model was established by oral administration of E.coli O1 to detect the intestinal mucosal permeability markers of calves, serum levels of immune factors and immunoglobulins. The results showed that the level of diamine oxidase(DAO) and endotoxin(ET) in diarrhea induced by Pathogenic E.coli O1 was significantly increased(P<0.05 or P>0.05);the levels of Tumor necrosis factor-α(TNF-α), Interleukin-6(IL-6) and IL-1β were significantly increased(P<0.05);the levels of IL-10, IL-4 and transforming growth factor-β(TGF-β) were decreased(P<0.05);the levels of immunoglobulin A(IgA) and IgM were significantly reduced(P<0.05), the level of IgG was decreased but not significantly(P>0.05). It indicated that diarrhea induced by Pathogenic E.coli O1 could increase the intestinal mucosal permeability, damage the intestinal mucosal barrier and reduce the immune function of the calf.