本试验通过连续3 d腹腔注射免疫抑制剂环磷酰胺( cyclophosphamide,CTX)建立小鼠免疫抑制模型,研究解淀粉芽孢杆菌SC06对免疫抑制小鼠肠道细菌酶活性和肠黏膜屏障功能的影响。选取120只BALB/c小鼠(4周龄,雌性,体重10~16 g),随机分成3组,每组4个重复,每个重复10只。对照组饲喂基础饲粮,免疫抑制组和芽孢杆菌组分别饲喂基础饲粮和添加解淀粉芽孢杆菌SC06的试验饲粮(活菌数为1×105 CFU/g),并均在试验第1~3天连续3 d腹腔注射CTX 80μg/g BW。试验期为60 d。结果表明：与对照组相比,免疫抑制组小鼠盲肠和小肠内容物中各细菌酶(α-葡萄糖苷酶、β-葡萄糖苷酶、β-葡萄糖苷酸酶、α-半乳糖苷酶和β-半乳糖苷酶)以及小肠灌洗液中二胺氧化物酶(DAO)活性极显著降低(P<0.01),小肠灌洗液中一氧化氮(NO)含量及诱导型一氧化氮合成酶(iNOS)活性极显著升高(P<0.01),小肠灌洗液中促炎细胞因子增殖诱导配体(APRIL)、干扰素-γ(IFN-γ)、白细胞介素-6(IL-6)和白细胞介素-12(IL-12)及抗炎细胞因子白细胞介素-10(IL-10)含量极显著升高(P<0.01),说明腹腔注射CTX后小鼠肠道菌群发生紊乱,肠上皮细胞遭到破坏,肠黏膜屏障功能受损。解淀粉芽孢杆菌SC06可极显著提高免疫抑制小鼠盲肠内容物中β-葡萄糖苷酸酶和α-葡萄糖苷酶及小肠内容物中β-葡萄糖苷酸酶活性(P<0.01),分别极显著和显著提高小肠灌洗液中髓过氧化物酶(MPO)和分泌型磷脂酶A2(sPLA2)活性(P<0.01和P<0.05)。以上结果表明解淀粉芽孢杆菌SC06可在一定程度上提高免疫抑制小鼠的肠道益生菌数量,但仅能部分恢复免疫抑制小鼠的肠黏膜屏障功能。%This study was conducted to study the effects of Bacillus amyloliquefaciens SC06 on intestinal bacte-rial enzyme activities and intestinal mucosal barrier function of immunosuppressive mice. The model of immu-nosuppressive mice was built by intraperitoneal injection of cyclophosphamide ( CTX) for 3 days continuously. A total of 120 BALB/c mice (4-week-old, female and body weight of 10 to 16 g) were randomly divided into 3 groups with 4 replicates per group and 10 mice per replicate. The mice in control group and immunosuppres-sive group were all fed basal diet, and those in Bacillus group were fed the basal diet supplemented with Bacil-lus amyloliquefaciens SC06 (living bacteria count was 1 × 105 CFU/g). On the 1st to 3rd day of the experi-ment, the mice in immunosuppressive group and Bacillus group were intraperitoneally injected with 80 μg/g BW of CTX for 3 consecutive days. The experiment lasted for 60 days. The results showed as fol-lows: compared with the control group, the activities of bacterial enzymes ( includingα-glucosidase,β-gluco-sidase, β-glucuronidase, α-galactosidase and β-galactosidase) in cecal and small intestinal contents and diam-ine oxidase (DAO) in small intestinal lavage fluid were significantly decreased (P<0. 01), the content of ni-tric oxide ( NO) and the activity of inducible nitric oxide synthase ( iNOS) in small intestinal lavage fluid were significantly increased ( P <0 . 01 ) , and the contents of pro-inflammatory cytokines-aproliferation inducing-ligand (APRIL), interferon-γ(IFN-γ), interleukin-6 (IL-6) and interleukin-12 (IL-12) and anti-inflamma-tory cytokine-interleukin-10 ( IL-10 ) in small intestinal lavage fluid were significantly increased ( P<0 . 01 ) . It indicated that the intestinal flora of mice was disordered, and the intestinal mucosa epithelial cells and the in-testinal mucosal barrier function were damaged by intraperitoneal injection of CTX. Bacillus amyloliquefaciens SC06 could significantly increase the activities of β-glucuronidase and α-glucosidase in cecal contents and β-glucuronidase in small intestinal contents ( P<0 . 01 ) , and significantly increase the activities of myeloperoxi-dase ( MPO ) and secretory phospholipase A2 ( sPLA2 ) in small intestinal lavage fluid ( P <0 . 01 and P <0. 05, respectively). The results indicate that Bacillus amyloliquefaciens SC06 can increase the intestinal probi-otic count in a certain extent, but only can partially recover the intestinal mucosal barrier function.
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