Effects of space flight and IGF-1 on immune function.
We tested the hypothesis that insulin-like growth factor-1 (IGF-1) would ameliorate space flight-induced effects on the immune system. Twelve male, Sprague-Dawley rats, surgically implanted with mini osmotic pumps, were subjected to space flight for 10 days on STS-77. Six rats received 10 mg/kg/day of IGF-1 and 6 rats received saline. Flight animals had a lymphocytopenia and granulocytosis which were reversed by IGF-1. Flight animals had significantly higher corticosterone levels than ground controls but IGF-1 did not impact this stress hormone. Therefore, the reversed granulocytosis did not correlate with serum corticosterone. Space flight and IGF-1 also combined to induce a monocytopenia that was not evident in ground control animals treated with IGF-1 or in animals subjected to space flight but given physiological saline. There was a significant increase in spleen weights in vivarium animals treated with IGF-1, however, this change did not occur in flight animals. We observed reduced agonist-induced lymph node cell proliferation by cells from flight animals compared to ground controls. The reduced proliferation was not augmented by IGF-1 treatment. There was enhanced secretion of TNF, IL-6 and NO by flight-animal peritoneal macrophages compared to vivarium controls, however, O2(-) secretion was not affected. These data suggest that IGF-1 can ameliorate some of the effects of space flight but that space flight can also impact the normal response to IGF-1. Grant Numbers: NAGW-1197, NAGW-2328.
Chapes
S K
SK
Division of Biology, Kansas State University, USA. skcbiol@ksu.edu
Simske
S J
SJ
Forsman
A D
AD
Bateman
T A
TA
Zimmerman
R J
RJ
D000818:Animals; D003345:Corticosterone / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000276:immunology / Q000494:pharmacology*; D008213:Lymphocyte Activation / Q000187:drug effects / Q000502:physiology; D008214:Lymphocytes / Q000187:drug effects* / Q000276:immunology / Q000502:physiology; D016173:Macrophage Colony-Stimulating Factor / Q000378:metabolism; D008264:Macrophages / Q000187:drug effects* / Q000276:immunology / Q000502:physiology; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism; D009929:Organ Size; D051381:Rats; D017207:Rats, Sprague-Dawley; D013026:Space Flight; D013154:Spleen / Q000166:cytology / Q000502:physiology; D013950:Thymus Gland / Q000166:cytology / Q000502:physiology; D014893:Weightlessness
D016207:Cytokines; D009569:Nitric Oxide; D007334:Insulin-Like Growth Factor I; D016173:Macrophage Colony-Stimulating Factor; D003345:Corticosterone