Effects of spaceflight and PEG-IL-2 on rat physiological and immunological responses.
Sprague-Dawley rats were subjected to two 8-day spaceflights on the space shuttle. Rats housed in the National Aeronautics and Space Administration's animal enclosure were injected (iv or sc) with pegylated interleukin-2 (PEG-IL-2) or a placebo. We tested the hypothesis that PEG-IL-2 would ameliorate some of the effects of spaceflight. We measured body and organ weights; blood cell differentials; plasma corticosterone; colony-forming units (macrophage and granulocyte macrophage); lymphocyte mitogenic, superantigenic, and interferon-gamma responses; bone marrow cell and peritoneal macrophage cytokine secretion; and bone strength and mass. Few immunological parameters were affected by spaceflight. However, some spaceflight effects were observed in each flight. Specifically, peritoneal macrophage spontaneous secretion of tumor necrosis factor-alpha occurred in the first but not in the second flight. A significant monocytopenia and lymphocytopenia were detected in the second but not in the first flight. The second mission produced bone changes more consistent with past spaceflight investigations. PEG-IL-2 did not appear to be beneficial; however, this was mostly due to the lack of spaceflight effects. These studies reflect the difficulty in reproducing experimental models by using current space shuttle conditions.
Chapes
S K
SK
Division of Biology, Kansas State University, Manhattan, Kansas 66506, USA. skcbiol@ksu.edu
Simske
S J
SJ
Sonnenfeld
G
G
Miller
E S
ES
Zimmerman
R J
RJ
D000818:Animals; D001835:Body Weight / Q000187:drug effects / Q000502:physiology; D001854:Bone Marrow Cells / Q000187:drug effects / Q000502:physiology; D003114:Colony-Forming Units Assay; D003345:Corticosterone / Q000096:biosynthesis; D016207:Cytokines / Q000096:biosynthesis; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000096:biosynthesis; D007109:Immunity / Q000187:drug effects / Q000502:physiology*; D007376:Interleukin-2 / Q000031:analogs & derivatives* / Q000494:pharmacology; D007958:Leukocyte Count; D008198:Lymph Nodes / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D008297:Male; D009929:Organ Size / Q000187:drug effects / Q000502:physiology; D011092:Polyethylene Glycols; D051381:Rats; D017207:Rats, Sprague-Dawley; D013026:Space Flight; D013154:Spleen / Q000166:cytology / Q000187:drug effects / Q000502:physiology
D016207:Cytokines; D007376:Interleukin-2; C067245:interleukin-2, polyethylene glycol-modified; D011092:Polyethylene Glycols; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D003345:Corticosterone