Oral administration of Lactobacillus paracasei L9 attenuates PM2.5-induced enhancement of airway hyperresponsiveness and allergic airway response in murine model of asthma

• Published in: PloS one 2017-02, Vol.12 (2), p.e0171721
• Main Authors: Wang, Xifan, Hui, Yan, Zhao, Liang, Hao, Yanling, Guo, Huiyuan, Ren, Fazheng
• Format: Article
• Language: English
• Subjects: Administration, Oral; Air pollution; Allergies; Alveoli; Animal models; Animals; Aromatic hydrocarbons; Asthma; Asthma - drug therapy; Asthma - etiology; Asthma - immunology; Asthma - therapy; Biology and Life Sciences; Bronchoalveolar Lavage Fluid - cytology; Bronchoconstrictor Agents - pharmacology; Bronchoconstrictor Agents - therapeutic use; Bronchus; Cytokines; Disease Models, Animal; Education; Engineering research; Eosinophils - cytology; Eosinophils - immunology; Exposure; Female; Food allergies; Food science; Heavy metals; Hydrocarbons; Hypersensitivity; Hypersensitivity - drug therapy; Hypersensitivity - etiology; Hypersensitivity - immunology; Hypersensitivity - therapy; Immune response; Immune system; Immunoglobulin E; Immunoglobulin G; Immunology; Immunotherapy; Infiltration; Inflammation; Interferon; Interleukin 17; Interleukin 4; Laboratories; Lactobacillus paracasei; Lactobacillus paracasei - immunology; Lactobacillus rhamnosus; Leukocytes (eosinophilic); Lung - drug effects; Lung - immunology; Lung - pathology; Lymphocytes; Lymphocytes T; Medicine and Health Sciences; Methacholine; Methacholine Chloride - pharmacology; Methacholine Chloride - therapeutic use; Mice; Mice, Inbred BALB C; Neutrophils - cytology; Neutrophils - immunology; Nutrition; Oral administration; Ovalbumin; Ovalbumin - immunology; Particulate emissions; Particulate matter; Particulate Matter - toxicity; Polycyclic aromatic hydrocarbons; Probiotics; Probiotics - therapeutic use; Research and Analysis Methods; Respiratory tract; Studies; Th1 Cells - cytology; Th1 Cells - immunology; Th1 Cells - metabolism; Th2 Cells - cytology; Th2 Cells - metabolism; Urban areas; γ-Interferon
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0171721

This study investigated allergy immunotherapy potential of Lactobacillus paracasei L9 to prevent or mitigate the particulate matter 2.5 (PM2.5) enhanced pre-existing asthma in mice. Firstly, we used a mouse model of asthma (a 21-day ovalbumin (OVA) sensitization and challenge model) followed by PM2.5 exposure twice on the same day of the last challenge. PM2.5 was collected from the urban area of Beijing and underwent analysis for metals and polycyclic aromatic hydrocarbon contents. The results showed that PM2.5 exposure enhanced airway hyper-responsiveness (AHR) and lead to a mixed Th2/ IL-17 response in asthmatic mice. Secondly, the PM2.5 exposed asthmatic mice were orally administered with L9 (4×107, 4×109 CFU/mouse, day) from the day of first sensitization to the endpoint, for 20 days, to investigate the potential mitigative effect of L9 on asthma. The results showed that L9 ameliorated PM2.5 exposure enhanced AHR with an approximate 50% decrease in total airway resistance response to methacholine (48 mg/ml). L9 also prevented the exacerbated eosinophil and neutrophil infiltration in bronchoalveolar lavage fluid (BALF), and decreased the serum level of total IgE and OVA-specific IgG1 by 0.44-fold and 0.3-fold, respectively. Additionally, cytokine production showed that L9 significantly decreased T-helper cell type 2 (Th2)-related cytokines (IL-4, -5, -13) and elevated levels of Th1 related IFN-γ in BALF. L9 also reduced the level of IL-17A and increased the level of TGF-β. Taken together, these results indicate that L9 may exert the anti-allergic benefit, possibly through rebalancing Th1/Th2 immune response and modulating IL-17 pro-inflammatory immune response. Thus, L9 is a promising candidate for preventing PM exposure enhanced pre-existing asthma.