title: Radiation and primary response to lipopolysaccharide: bone marrow-derived cells and susceptible organs.
abstract: BACKGROUND
  The major goal of this study was to determine whether radiation significantly alters bone marrow-derived cell distribution and mass of sensitive organs after challenge with lipopolysaccharide (LPS).
  
  
  METHODS
  C57BL/6 mice were exposed whole-body to 0 or 3 gray (Gy) gamma-radiation (60Co) and injected intraperitoneally with 0.1 ml saline or 1 mg/kg LPS (E. coli serotype 0111:B4) 10 days later. Subsets from each group were euthanized at 60 min and 1, 7 and 14 days post-injection for analyses.
  
  
  RESULTS
  Body mass was low 1 day after LPS, especially in irradiated animals. LPS-induced splenomegaly and hepatomegaly were attenuated by radiation, whereas thymic atrophy was enhanced. However, radiation had no effect on LPS-induced changes in oxygen radical production by liver phagocytes. The numbers of all major leukocyte populations (lymphocytes, monocyte-macrophages, granulocytes) were altered by both radiation and LPS at virtually all time points of testing. In general, the LPS-induced changes in leukocytes were diminished by radiation. Significant radiation x LPS interactions were especially prominent at day 1 after LPS administration. In contrast, mice receiving both radiation and LPS had lower red blood cell (RBC) and platelet counts than those receiving either agent alone.
  
  
  CONCLUSIONS
  The data show that radiation had a highly significant influence on LPS-induced changes in mass of several body organs, leukocytes, RBC, and platelets, and thus may increase severity of infection due to Gram-negative bacteria.
authors.affiliation: Department of Radiation Medicine, Molecular Radiation Biology Laboratories, and Loma Linda University and Medical Center, Loma Linda, CA 92354, USA. dgridley@dominion.llumc.edu
authors.forename: Daila S
authors.initials: DS
authors.lastname: Gridley
authors.forename: Glen M
authors.initials: GM
authors.lastname: Miller
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Pecaut
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000187:drug effects / Q000473:pathology / Q000528:radiation effects; D001854:Bone Marrow Cells / Q000187:drug effects* / Q000528:radiation effects*; D004906:Erythrocyte Count; D004912:Erythrocytes / Q000187:drug effects / Q000473:pathology / Q000528:radiation effects; D004926:Escherichia coli; D005260:Female; D005720:Gamma Rays; D007274:Injections, Intraperitoneal; D007962:Leukocytes / Q000187:drug effects / Q000473:pathology / Q000528:radiation effects; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008099:Liver / Q000187:drug effects / Q000473:pathology* / Q000528:radiation effects; D051379:Mice; D008810:Mice, Inbred C57BL; D009929:Organ Size / Q000187:drug effects / Q000528:radiation effects; D010976:Platelet Count; D013154:Spleen / Q000187:drug effects / Q000473:pathology* / Q000528:radiation effects; D013950:Thymus Gland / Q000187:drug effects / Q000473:pathology* / Q000528:radiation effects; D014916:Whole-Body Irradiation
chemical_list: D008070:Lipopolysaccharides