广叶绣球菌多糖对免疫低下小鼠肠道免疫功能的调节作用

通过研究广叶绣球菌多糖对免疫低下小鼠肠道菌群、细胞因子表达量及短链脂肪酸的影响,探究广叶绣球菌多糖的免疫作用机制。腹腔注射环磷酰胺构建免疫低下小鼠模型,将小鼠分为6组：正常对照组、模型组、广叶绣球菌多糖低、中、高剂量组以及阳性对照组,连续饲养30d后处死取样,HE染色观察小肠组织结构,酶联免疫吸附法测定小肠白细胞介素-6（IL-6）、IL-10、肿瘤坏死因子-α（TNF-α）、干扰素-γ（IFN-γ）的表达水平,高通量测序技术分析小鼠肠道菌群的变化,气-质联用（GC-MS）技术分析盲肠内容物短链脂肪酸（SCFAs）的含量。结果表明,广叶绣球菌多糖高剂量组可显著改善绒毛肿胀和变短现象,提高绒毛长度/隐窝深度的比值（V/C值）和小肠IL-6、IL-10、TNF-α、IFN-γ细胞因子含量（P<0.05或P<0.01）,提高拟杆菌属Bacteroides、拟普雷沃菌属Alloprevotella、丁酸弧菌属Butyrivibrio、Intestinimonas、链球菌属Streptococcus的相对丰度（P<0.05或P<0.01）;各剂量组均可提高盲肠内6种主要短链脂肪酸含量,差异达显著或极显著水平（P<0.05或P<0.01）。试验组与阳性对照组趋势一致。广叶绣球菌多糖可通过改善免疫低下小鼠的肠道粘膜形态,提高小肠细胞因子水平,调节肠道菌群结构,增加SCFAs产生菌的相对丰度,提高短链脂肪酸含量,调节免疫低下小鼠的肠道免疫功能。

Regulatory effects of Sparassis latifolia polysaccharide on intestinal immune function in immunosuppressed mice

The immunifaction mechanism of Sparassis latifolia polysaccharide (SLP) was explored by observing the effects of SLP on intestinal microflora, expression of cytokines and short chain fatty acids in immunocompromised mice. The immunosuppressive mice model was established by intraperitoneal injection of cyclophosphamide for 3 consecutive days. The mice were randomly divided into 6 groups: normal control group, model group, low, medium and high dose Sparassis latifolia polysaccharide group, and positive group. The experiment lasted for 30 days. The tissue section of small intestine was determined by hematoxylin-eosin (H-E) staining. The levels of interleukin-6 (IL-6), interleukin-10 (IL-10), tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) in the small intestine was measured by enzyme-linked immunosorbent assay. The changes of intestinal microflora were analyzed by high-throughput sequencing. The content of short chain fatty acids (SCFAs) in cecal were analyzed by gas chromatography-mass spectrometry (GC/MS). Administration high dose of SLP can significantly improve the swelling and shortening of villi, increase the ratio of villi length to crypt depth (V/C value), increase the levels of IL-6, IL-10, TNF-α, IFN-γ in small intestine (P<0.05 or P<0.01), and improve the relative abundances of Bacteroides, Alloprevotella, Butyrivibrio, Integinimonas and Streptococcus (P<0.05 or P<0.01); the content of six main short chain fatty acids in cecum of each dose group were significantly increased (P<0.05 or P<0.01). The trends of the test groups were the same as that of the positive control group. SLP can effectively regulate the intestinal immune function of immunosuppressed mice by improving intestinal mucosal morphology, increasing the levels of intestinal cytokines, modulating the structure of gut microbiota, increasing the relative abundance of SCFAs-producing bacteria and promoting the content of short chain fatty acids, etc., and increase the content of short-chain fatty acids in the cecum to regulate the intestinal immune function of immunosuppressed mice.