Effect of combination treatment with Lactobacillus rhamnosus and corticosteroid in reducing airway inflammation in a mouse asthma model.

BACKGROUND: Asthma is a complex multifactorial chronic airway inflammatory disease with diverse phenotypes and levels of severity and is associated with significant health and economic burden. In a certain population of asthma patients, the symptoms cannot be well controlled with steroid. There has been long standing interest in the use of probiotics for treating allergic diseases. The purpose of this study is to investigate whether the combination of Lactobacillus rhamnosus GG (LGG) with prednisolone could reduce the dosage of glucocorticoid in controlling airway inflammation in a murine model for allergic asthma. MATERIAL AND METHODS: We used Der p 2-sensitized asthma model in female BALB/c mice. The animals were treated with 75 µl or 50 µl oral prednisolone or combination treatment of these two doses of oral prednisolone with LGG. Airway hyperresponsiveness, serum specific IgE/IgG1/IgG2a, infiltrating inflammatory cells in lung and cytokines were assessed. RESULTS: Compared to 75 µl prednisolone, a lower dose of prednisolone with 50 µl was less satisfactory in suppressing airway hyperresponsives, serum IgE and IgG1, Th2 cytokines and inflammatory cytokines such as IL-6, IL-8 and IL-17 as well as infiltrating inflammatory cells. However, combination of 50 µl prednisolone and LGG decreased airway resistance and serum IgE and IgG1, inhibited the production of IL-4, IL-5, IL-6, IL-8, IL-13 and IL-17, upregulated serum IgG2a and enhanced Th1 immune response. CONCLUSIONS: LGG may reduce the dosage of prednisolone and thus may be beneficial in the treatment of asthma.