title: Tissue apoptosis in mice infected with Leptospira interrogans serovar Icterohaemorrhagiae.
abstract: BACKGROUND
  This investigation aimed to evaluate the occurrence of some apoptotic features induced by Leptospira interrogans serovar Icterohaemorrhagiae infection in young BALB/c mice during 2, 4, 7, 10, 14 and 21 days post-infection (dpi).
  
  
  METHODS
  The animals were euthanized and lung, liver and kidneys were harvested to histopathology analysis and immunohistochemistry to caspase-3 antigen detection was performed.
  
  
  RESULTS
  Chromatin condensation in kidney and liver tissues, but not in lung tissue, was observed. Caspase-3 reactive cells, mainly characterized as renal epithelial cells, were detected in the days 14 and 21 at high levels when compared to days 2, 4 and 7 (p = 0.025; p < 0.05). Lung sections revealed caspase-3 labeled alveolar cells in 10 and 14 days post-infection was higher than observed at 7 days (p = 0.0497; p < 0.05). Liver sections demonstrated reactive cells at a highest level at 14 and 21 days post-infection when comparison to 2, 4, 7 and 10 days (p = 0.0069; p < 0.05).
  
  
  CONCLUSIONS
  Our results suggest that infection of L. interrogans induce in kidney, liver and lung an activation of apoptosis mediated by caspase-3 dependent pathway in later phases of infectious process.
authors.affiliation: Department of Support, Production and Animal Health, Veterinary Medicine School, São Paulo State University (UNESP - Univ Estadual Paulista), Araçatuba, São Paulo Brazil.
authors.forename: Márcia
authors.initials: M
authors.lastname: Marinho
authors.affiliation: Department of Support, Production and Animal Health, Veterinary Medicine School, São Paulo State University (UNESP - Univ Estadual Paulista), Araçatuba, São Paulo Brazil.
authors.forename: Cilene Vidovix
authors.initials: CV
authors.lastname: Táparo
authors.affiliation: Department of Inflammatory Mediators, Anesthesiology, Pain and Intensive Care, UNIFESP, São Paulo, São Paulo Brazil.
authors.forename: Itamar S
authors.initials: IS
authors.lastname: Oliveira-Júnior
authors.affiliation: Department of Support, Production and Animal Health, Veterinary Medicine School, São Paulo State University (UNESP - Univ Estadual Paulista), Araçatuba, São Paulo Brazil.
authors.forename: Silvia Helena Venturoli
authors.initials: SH
authors.lastname: Perri
authors.affiliation: Department of Support, Production and Animal Health, Veterinary Medicine School, São Paulo State University (UNESP - Univ Estadual Paulista), Araçatuba, São Paulo Brazil.
authors.forename: Tereza Cristina
authors.initials: TC
authors.lastname: Cardoso
keywords: Caspases; Inflammatory response; Leptospirosis; Mice; Programmed cell death