Preventive effects of probiotics on asthmatic lung inflammation in an ovalbumin-induced murine model

Background: Asthma, a prevalent chronic inflammatory lung disease that has affected over 330 million people worldwide, manifests through symptoms such as wheezing, coughing, dyspnea, and chest tightness. Probiotics, such as L. rhamnosus and B. subtilis , confer beneficial effects on allergic airway inflammation. They induce regulatory immune responses and offer the potential to restore cytokine balance in activated immune cells. Therefore, in this study, we aimed to investigate the effects of probiotics on inflammation in pulmonary diseases by assessing their impact on airway resistance, immune cell infiltration, and allergy-related chemokine levels in an ovalbumin (OVA)-induced asthmatic mouse model. Methods Mice were sensitized to OVA through intraperitoneal injections of OVA alum on Days 0 and 7. Subsequently, the mice were subjected to aerosolized OVA challenges three times weekly from Day 14 to 28. The mice were then administered tri-weekly oral doses of L. rhamnosus or B. subtilis approximately 1 week before sensitization. Tidal volume and specific airway resistance were assessed via a methacholine test. The number of cells in lung bronchoalveolar lavage fluid (BALF) was counted to assess inflammatory cell infiltration. An enzyme-linked immunosorbent assay was used to measure the protein levels of IL-13 in the BALF and the levels of antibodies, including OVA-specific immunoglobulin E (IgE) and OVA-specific IgG1, in the serum. Furthermore, the lungs were subjected to histopathological analysis. Results The oral administration of B. subtilis and L. rhamnosus significantly decreased airway resistance, suppressed immune cell infiltration, and inhibited the production of allergy-related antibodies, including IgE and IgG1. Furthermore, B. subtilis and L. rhamnosus decreased the production of IL-13, which induces mucin production; mucin production was decreased in the B. subtilis and L. rhamnosus groups. Conclusions This study demonstrated that oral administration of probiotics could have a potential preventive effect on asthmatic lung inflammation.