Hippocampal neurogenesis and PSA-NCAM expression following exposure to 56Fe particles mimics that seen during aging in rats.
Exposure to particles of high energy and charge can disrupt the neuronal systems as well as the motor and cognitive behaviors mediated by these systems in a similar fashion to that seen during the aging process. In the hippocampus, adult neurogenesis is affected both by aging and irradiation with ionizing particles. Likewise, the maturation of newly formed cells in this region as measured by PSA-NCAM expression is also altered by the aging process. The present study was designed to investigate the effects of 2.5 Gy of 1 GeV/n (56)Fe particles on neurogenesis using the nuclear proliferation marker 5-bromodeoxyuridine (BrdU and PSA-NCAM expression in the dentate gyrus of rats exposed to whole-body irradiation or simply placed in the chamber without being irradiated. All subjects (n=10) were sacrificed 28 days after the last BrdU injection (50 mg/kg X 3 days) and their brains were processed for immunohistochemistry. Results illustrate a decrease in the number of BrdU-positive cells as well as different distribution of these cells in the dentate gyrus of irradiated animals. Additionally, irradiated subjects show decreased levels of PSA-NCAM expression. These changes are consistent with those found in aged subjects indicating that heavy-particle irradiation is an adequate model for the study of aging.
Casadesus
Gemma
G
VSDA, HNRC on Aging, Tufts University, Boston, MA, USA. gxc40@case.edu
Shukitt-Hale
Barbara
B
Stellwagen
Heather M
HM
Smith
Mark A
MA
Rabin
Bernard M
BM
Joseph
James A
JA
D000375:Aging / Q000502:physiology*; D000818:Animals; D015415:Biomarkers / Q000032:analysis; D001973:Bromodeoxyuridine / Q000032:analysis; D049109:Cell Proliferation; D018891:Dentate Gyrus / Q000737:chemistry / Q000502:physiology; D006624:Hippocampus / Q000737:chemistry / Q000166:cytology / Q000502:physiology*; D007501:Iron / Q000494:pharmacology*; D008297:Male; D008855:Microscopy, Electron, Scanning; D039842:Neural Cell Adhesion Molecule L1 / Q000032:analysis*; D011839:Radiation, Ionizing; D051381:Rats; D017207:Rats, Sprague-Dawley; D012794:Sialic Acids / Q000032:analysis*; D014916:Whole-Body Irradiation
D015415:Biomarkers; D039842:Neural Cell Adhesion Molecule L1; D012794:Sialic Acids; C103469:polysialyl neural cell adhesion molecule; D007501:Iron; D001973:Bromodeoxyuridine