CERELA   05438
CENTRO DE REFERENCIA PARA LACTOBACILOS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Lactobacillus rhamnosus CRL 1505 improves respiratory and systemic innate immunity in malnourished mice
Autor/es:
HERRERA MATÍAS; SALVA SUSANA; VILLENA JULIO; BARBIERI NATALIA; ALVAREZ SUSANA
Lugar:
San Miguel de Tucumán. Tucumán. Argentina
Reunión:
Simposio; III International Symposium on Lactic Acid Bacteria. II Argentinean LAB Net Meeting; 2009
Institución organizadora:
CERELA-CONICET
Resumen:
We demonstrated previously that the oral administration of Lactobacillus rhamnosus CRL 1505 (Lr) to malnourished mice, was capable of improving resistance against Streptococcus pneumoniae. In this work we studied the effect of Lr on the innate immune response against the respiratory pathogen. Weaned mice were malnourished after consuming a protein-free diet (PFD) for 21 days. Malnourished mice were fed a balanced conventional diet (BD) for 7 days (BD group) or BD for 7 days with supplemental Lr (108 cells/mouse/day) from day 3 to day 7 (BD+Lr group). The malnourished control group (MNC) received PFD while the well-nourished control (WNC) mice consumed BD. At the end of treatments the different groups of mice were infected nasally with S. pneumoniae (105 cells/mouse). We analyzed in bronco-alveolar lavages (BAL), blood and bone marrow (BM): a) the total and differential cell counts, b) activity of phagocytes, and c) Gr-1 and CD34 expression with flow cytometry. Before the challenge, we observed that malnutrition induced a decrease of the population of granulocytes in both blood and BM (FSC vs SSC), being the mature myeloid cells (Gr-1high) the main population responsible for this effect (Blood neutrophils: WNC=0.9±0.07 109cells/l; MNC=0.6±0.08; BD=0.7±0.03; BD+Lr=0.9±0.07; BM Gr-1+ cells: WNC=21.8±2.1 106 cells/femur; MNC=13.5±1.8; BD=14.9±1.0; BD+Lr=21.2±1.6). In addition, MNC mice showed lower neutrophils peroxidase activity than WNC group. The treatment with BD+Lr was able to normalize the number of blood and BM Gr-1high cells (p<0.05) and improved neutrophils peroxidase activity. Challenge with the pathogen increase the number of respiratory phagocytes in all experimental groups, however, MNC showed impaired respiratory phagocytes activity and neutrophils recruitment into the lungs. BD+Lr mice showed values of neutrophils in BAL similar to those of WNC mice and the activation of phagocytic cells was significantly higher when compared with all the experimental groups (BAL NBT+ cells: WNC=46.8±2.2 %; MNC=37.3±3.1; BD=40.2±0.9; BD+Lr=56.0±1.3). Infection increase the number of blood and BM GR-1 cells in all groups; however, in MNC and BD it was observed an increase of BM Gr-1high cells, while in WNC and BD+Lr there was an increase of BM Gr-1low cells. (BM Gr-1high cells: WNC=5.9±0.6 106 cells/femur; MNC=7.4±0.9; BD=7.3±0.3; BD+Lr=4.7±0.4; BM Gr-1low cells: WNC=13.6±1.3 106 cells/femur; MNC=3.2±0.4; BD=9.7±0.6; BD+Lr=14.7±1.1). The challenge with the respiratory pathogen increase the number of BM immature myeloid cells (Gr-1+/CD34+) in all experimental groups; however, the levels of these cells in the MNC and BD groups were lower than the other groups (BM Gr-1+/CD34+ cells: WNC=7.2±0.7 106 cells/femur; MNC=2.4±0.3; BD=4.0±0.3; BD+Lr=4.9±0.3). Results showed that oral administration of L. rhamnosus CRL 1505 is able to improve the innate immune response against S. pneumoniae in malnourished immunocompromised mice. This effect would be related to the ability of L. rhamnosus CRL 1505 to induce an early recovery of myeloid cells in blood and BM.