A new way of delivering probiotic bacteria in a murine model

Introduction: Health-promoting benefits of probiotics have been demonstrated in gastrointestinal domain after oral administration. Evidences show that probiotics communicate with the host by modulating key signaling pathways in gastrointestinal lymphoid associated tissue (G.A.L.T.). In order to understand how probiotic agents act within deep respirator y tract, we have developed a mouse model of respirator y deliver y, in attempt to examine the effects of Lactobacillus brevis (strain Cd2 Dsm 11988) administration in the pulmonary environment, in terms of host responses, survival rate, modifications of resident microbiota, gross- and histological modifications. Materials and Methods: Thirty CD1-male mice were exposed daily, to different dosage of aerosolised Lactobacillus brevis, for five days. After treatment, mice were euthanised and airways, lungs and bronchoalveolar lavage fluid (B.A.L.F.) were collected and processed for histopathological studies, and microbiota analysis. We analysed mucosal modification and cell response in lungs through histological and immunohistochemical evaluations, using several antibodies to immunophenotyping the immunitar y response. Results: Respirator y deliver y of probiotic bacteria was well tolerated in mice, resulting in mild to absent inflammator y reaction in airways mucosa and lung’s parenchyma. A considerable hyperplasia of the bronchial-associated lymphoid tissue (B.A.L.T.) and an increased number of pulmonar y intravascular and alveolar macrophages was also documented. Analysis of microbioma showed an interesting modulation of respirator y tract-resident bacterial populations. Discussion (and/or Conclusions): Our newly murine model of probiotic deliver y may be useful in attempt to positively modulate the airways/lung response to different pathogens. Our results suggest that probiotic can be used as a novel therapeutic or preventative strategy to manage respirator y diseases.