植物乳杆菌Sc52对脂多糖诱导小鼠肠道屏障损伤的保护作用

目的:研究植物乳杆菌(Lactobacillus plantarum)Sc52对脂多糖(lipopolysaccharide,LPS)诱导小鼠肠道屏障损伤的保护作用。方法:选取6周龄雄性ICR小鼠,随机分为3组,实验组每天灌胃植物乳杆菌Sc52(1010 CFU/d),空白组与模型组灌胃等量生理盐水,连续两周后,除空白组外,一次性腹腔注射LPS(15 mg/kg)建立小鼠肠屏障损伤模型。检测小鼠血清中炎症因子及与肠道通透性相关指标水平,苏木精-伊红染色观察回肠组织病理学变化,气相色谱法测定小鼠肠道短链脂肪酸水平,平板计数法分析小鼠粪便中主要菌群数量,蛋白质印记法分析小鼠回肠上皮细胞间紧密连接蛋白表达水平。结果:预先灌胃植物乳杆菌Sc52能够降低小鼠血清中肿瘤坏死因子、白细胞介素-6、白细胞介素-12、一氧化氮等炎症相关因子水平。植物乳杆菌Sc52通过调节D-乳酸和二胺氧化酶的水平,改善肠道通透性。灌胃植物乳杆菌Sc52能够提高小鼠肠道中乙酸和丁酸含量,能够增加小鼠肠道中乳杆菌、双歧杆菌等有益微生物的数量,抑制有害微生物的生长;显著上调回肠组织中紧密连接蛋白Occludin和Claudin-1的表达。结论:植物乳杆菌Sc52对小鼠肠道屏障功能具有保护作用。

Protective Effect of Lactobacillus plantarum Sc52 on LPS-Induced Intestinal Barrier Injury in Mice

Objective: To study the protective effect of Lactobacillus plantarum Sc52 on lipopolysaccharide (LPS)-induced mouse intestinal barrier injury. Methods: Six-week-old male ICR mice were randomly divided into 3 groups. L. plantarum Sc52 was fed to the mice in the experimental group by gavage at a dose of 1010 CFU/d for 14 consecutive days, while the mice in the control and model groups were given an equal volume of normal saline. Then, all mice except those in the control group were intraperitoneally injected with LPS to establish an intestinal barrier injury model. The levels of inflammatory cytokines in serum and intestinal permeability-related parameters were measured by enzyme-linked immunosorbent assay (ELISA). The histopathological changes of the ileum were tested by hematoxylin-eosin staining. The contents of shortchain fatty acids in colonic contents were determined by gas chromatography and the major intestinal bacteria in feces were enumerated by plate counting. The expression of intestinal tight junction protein was examined by Western blot. Results: Intragastric administration of L. plantarum Sc52 could inhibit the increase of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-12 (IL-12) and nitric oxide (NO). In addition, L. plantarum Sc52 could improve intestinal permeability by regulating D-lactic acid and diamine oxidase levels in the serum of mice. Furthermore, after administration of L. plantarum Sc52, the contents of acetic acid and butyric acid in colonic contents were increased, the number of Lactobacilli, Bifidobacterium and other beneficial microorganism were also significantly increased, and the number of harmful bacteria was decreased. Moreover, the expression of tight junction protein in the ileum was up-regulated. Conclusion: L. plantarum Sc52 can effectively protect against intestinal barrier injury caused by LPS in mice.