title: Dietary Fiber Intake Regulates Intestinal Microflora and Inhibits Ovalbumin-Induced Allergic Airway Inflammation in a Mouse Model.
abstract: BACKGROUND
  Recently, academic studies suggest that global growth of airway allergic disease has a close association with dietary changes including reduced consumption of fiber. Therefore, appropriate dietary fiber supplementation might be potential to prevent airway allergic disease (AAD).
  
  
  OBJECTIVE
  We investigated whether dietary fiber intake suppressed the induction of AAD and tried to elucidate the possible underlying mechanisms.
  
  
  METHODS
  The control mice and AAD model mice fed with 4% standard-fiber chow, while low-fiber group of mice fed with a 1.75% low-fiber chow. The two fiber-intervened groups including mice, apart from a standard-fiber diet, were also intragastric (i.g.) administrated daily with poorly fermentable cellulose or readily fermentable pectin (0.4% of daily body weight), respectively. All animals except normal mice were sensitized and challenged with ovalbumin (OVA) to induce airway allergic inflammation. Hallmarks of AAD were examined by histological analysis and ELISA. The variation in intestinal bacterial composition was assessed by qualitative analysis of 16S ribosomal DNA (rDNA) content in fecal samples using real-time PCR.
  
  
  RESULTS
  Low-fiber diet aggravated inflammatory response in ovalbumin-induced allergic mice, whereas dietary fiber intake significantly suppressed the allergic responses, attenuated allergic symptoms of nasal rubbing and sneezing, decreased the pathology of eosinophil infiltration and goblet cell metaplasia in the nasal mucosa and lung, inhibited serum OVA-specific IgE levels, and lowered the levels of Th2 cytokines in NALF and BALF, but, increased Th1 (IFN-γ) cytokines. Additionally, dietary fiber intake also increased the proportion of Bacteroidetes and Actinobacteria, and decreased Firmicutes and Proteobacteria. Levels of probiotic bacteria, such as Lactobacillus and Bifidobacterium, were upgraded significantly.
  
  
  CONCLUSIONS
  Long-term deficiency of dietary fiber intake increases the susceptibility to AAD, whereas proper fiber supplementation promotes effectively the balance of Th1/Th2 immunity and then attenuates allergic inflammatory responses significantly, as well as optimizes the structure of intestinal microbiota, which suggests potential for novel preventive and therapeutic intervention.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, P.R. China.|Shandong Institute of Otolaryngology, Shandong Provincial Key Laboratory of Otology, Jinan, P.R. China.
authors.forename: Zhiyu
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, P.R. China.
authors.forename: Lei
authors.initials: L
authors.lastname: Shi
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Affiliated Eye, Ear, Nose, and Throat Hospital, Fudan University, Shanghai, China.
authors.forename: Wenhui
authors.initials: W
authors.lastname: Pang
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, P.R. China.|Shandong Institute of Otolaryngology, Shandong Provincial Key Laboratory of Otology, Jinan, P.R. China.
authors.forename: Wenwen
authors.initials: W
authors.lastname: Liu
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, P.R. China.|Shandong Institute of Otolaryngology, Shandong Provincial Key Laboratory of Otology, Jinan, P.R. China.
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, P.R. China.|Shandong Institute of Otolaryngology, Shandong Provincial Key Laboratory of Otology, Jinan, P.R. China.
authors.forename: Haibo
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, P.R. China.|Shandong Institute of Otolaryngology, Shandong Provincial Key Laboratory of Otology, Jinan, P.R. China.
authors.forename: Guanggang
authors.initials: G
authors.lastname: Shi
mesh_terms: D000818:Animals; D041963:Bacteroidetes / Q000187:drug effects / Q000254:growth & development; D001644:Bifidobacterium / Q000187:drug effects / Q000254:growth & development; D002482:Cellulose / Q000008:administration & dosage; D004043:Dietary Fiber / Q000627:therapeutic use*; D004195:Disease Models, Animal; D004804:Eosinophils / Q000187:drug effects / Q000276:immunology; D005243:Feces / Q000382:microbiology; D005260:Female; D000069196:Gastrointestinal Microbiome / Q000187:drug effects* / Q000276:immunology; D020397:Goblet Cells / Q000187:drug effects / Q000276:immunology; D006801:Humans; D007073:Immunoglobulin E / Q000096:biosynthesis; D007249:Inflammation; D007422:Intestines / Q000187:drug effects* / Q000276:immunology / Q000382:microbiology; D007778:Lactobacillus / Q000187:drug effects / Q000254:growth & development; D008168:Lung / Q000187:drug effects / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D009297:Nasal Mucosa / Q000187:drug effects / Q000276:immunology; D010047:Ovalbumin; D010368:Pectins / Q000008:administration & dosage; D020560:Proteobacteria / Q000187:drug effects / Q000254:growth & development; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012130:Respiratory Hypersensitivity / Q000139:chemically induced / Q000178:diet therapy* / Q000276:immunology* / Q000382:microbiology; D058408:Th1-Th2 Balance / Q000187:drug effects
chemical_list: D004043:Dietary Fiber; D012336:RNA, Ribosomal, 16S; D007073:Immunoglobulin E; D010368:Pectins; D002482:Cellulose; D010047:Ovalbumin