Changes in mouse thymus and spleen after return from the STS-135 mission in space.
Our previous results with flight (FLT) mice showed abnormalities in thymuses and spleens that have potential to compromise immune defense mechanisms. In this study, the organs were further evaluated in C57BL/6 mice after Space Shuttle Atlantis returned from a 13-day mission. Thymuses and spleens were harvested from FLT mice and ground controls housed in similar animal enclosure modules (AEM). Organ and body mass, DNA fragmentation and expression of genes related to T cells and cancer were determined. Although significance was not obtained for thymus mass, DNA fragmentation was greater in the FLT group (P<0.01). Spleen mass alone and relative to body mass was significantly decreased in FLT mice (P<0.05). In FLT thymuses, 6/84 T cell-related genes were affected versus the AEM control group (P<0.05; up: IL10, Il18bp, Il18r1, Spp1; down: Ccl7, IL6); 15/84 cancer-related genes had altered expression (P<0.05; up: Casp8, FGFR2, Figf, Hgf, IGF1, Itga4, Ncam1, Pdgfa, Pik3r1, Serpinb2, Sykb; down: Cdc25a, E2F1, Mmp9, Myc). In the spleen, 8/84 cancer-related genes were affected in FLT mice compared to AEM controls (P<0.05; up: Cdkn2a; down: Birc5, Casp8, Ctnnb1, Map2k1, Mdm2, NFkB1, Pdgfa). Pathway analysis (apoptosis signaling and checkpoint regulation) was used to map relationships among the cancer-related genes. The results showed that a relatively short mission in space had a significant impact on both organs. The findings also indicate that immune system aberrations due to stressors associated with space travel should be included when estimating risk for pathologies such as cancer and infection and in designing appropriate countermeasures. Although this was the historic last flight of NASA's Space Shuttle Program, exploration of space will undoubtedly continue.
Department of Basic Sciences, Division of Radiation Research, Loma Linda University, Loma Linda, California, United States of America.
Daila S
DS
Gridley
Xiao Wen
XW
Mao
Louis S
LS
Stodieck
Virginia L
VL
Ferguson
Ted A
TA
Bateman
Maria
M
Moldovan
Christopher E
CE
Cunningham
Tamako A
TA
Jones
Jerry M
JM
Slater
Michael J
MJ
Pecaut
D000818:Animals; D053938:DNA Fragmentation; D005247:Feeding Behavior; D005260:Female; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D051379:Mice; D008954:Models, Biological; D015513:Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D009929:Organ Size; D015398:Signal Transduction; D013026:Space Flight; D013154:Spleen / Q000033:anatomy & histology / Q000502:physiology*; D013950:Thymus Gland / Q000033:anatomy & histology / Q000502:physiology*; D014893:Weightlessness
D015513:Oncogene Proteins