title: Prophylactic administration of Withania somnifera extract increases host resistance in Listeria monocytogenes infected mice.
abstract: In this study, we demonstrated that Withania somnifera L. extract (WSE) protects mice from a lethal dose of Listeria monocytogenes when administered prophylactically at 100, 250 and 500 mg/kg for 10 days, with survival rates up to 30%. These doses also prevented the myelosuppression and the splenomegaly caused by a sublethal infection with L. monocytogenes, due to increased numbers of granulocyte-macrophage progenitors (CFU-GM) in the bone marrow. Investigation of the production of colony-stimulating factors (CSFs) revealed increased colony-stimulating activity (CSA) in the serum of normal and infected mice pre-treated with WSE. Further studies to investigate the levels of interferon-gamma (INF-gamma) and lymphocyte cell proliferation were undertaken. We observed dose-dependent increases in cell proliferation and in the levels of INF-gamma in mice infected with L. monocytogenes and treated with WSE. All together, our results suggest that WSE indirectly modulates immune activity and probably disengages Listeria-induced suppression of these responses by inducing a higher reserve of myeloid progenitors in the bone marrow, proliferation of lymphocytes and increased INF-gamma levels.
authors.affiliation: Fisiopatologia Médica, Faculdade de Ciências Médicas, FCM, Universidade Estadual de Campinas, UNICAMP, Campinas, SP, Brazil.
authors.forename: Silvia T
authors.initials: ST
authors.lastname: Teixeira
authors.forename: Marize C
authors.initials: MC
authors.lastname: Valadares
authors.forename: Shirley A
authors.initials: SA
authors.lastname: Gonçalves
authors.forename: Adriana
authors.initials: A
authors.lastname: de Melo
authors.forename: Mary L S
authors.initials: ML
authors.lastname: Queiroz
mesh_terms: D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects; D004195:Disease Models, Animal; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000276:immunology; D007371:Interferon-gamma / Q000276:immunology; D008089:Listeria monocytogenes / Q000254:growth & development; D008088:Listeriosis / Q000276:immunology / Q000382:microbiology / Q000473:pathology / Q000517:prevention & control*; D008214:Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D010936:Plant Extracts / Q000302:isolation & purification / Q000627:therapeutic use; D013154:Spleen / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D032341:Withania / Q000737:chemistry*
chemical_list: D010936:Plant Extracts; D007371:Interferon-gamma; D016178:Granulocyte-Macrophage Colony-Stimulating Factor