Gamma-ray susceptibility of immature and mature hippocampal cultured cells.
Ionizing radiation suppresses neurogenesis in the mammalian brain. This in vitro study compared the detrimental effect of acute gamma-irradiation on immature hippocampal cells with mature cells. Both rat immature (0.5 day in vitro (DIV)) and mature hippocampal cells (14 DIV) were irradiated with 0-4 Gy gamma-rays. Cell viability was analyzed by using a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay. DNA fragmentation study was performed by extracting intracellular DNA. Morphological features of apoptosis were characterized by 4',6-diamidine-2'-phenylindole, dihydrochloride (DAPI) staining. MTT assay revealed that the survival rate of immature hippocampal cells declined in a dose-dependent manner within the range of irradiation applied, but was not changed in mature cells. Intranucleosomal DNA fragmentation in a ladder like pattern was dose-dependently increased in immature cells, but not in mature cells. The number of apoptotic nuclei in immature cells increased significantly in a dose-dependent manner within the range of irradiation applied. Active caspase-3 and cleaved poly (ADP-ribose) polymerase (PARP) expressions in immature hippocampal cells at 6 hr after 2 Gy exposure were markedly higher than control levels. The significantly greater radiosensitivity of immature hippocampal cells than that of the mature cells, indicates that the susceptibility of such hippocampal cells depends on their maturation. In addition, gamma-irradiation may induce caspase-dependent apoptosis in immature hippocampal cells.
Song
Myoung-Sub
MS
College of Veterinary Medicine and Animal Medical Institute, Chonnam National University, Gwangju 500-757.
Kim
Joong-Sun
JS
Yang
Miyoung
M
Kim
Sung-Ho
SH
Kim
Jong-Choon
JC
Park
Soo Hyun
SH
Shin
Taekyun
T
Moon
Changjong
C
D000818:Animals; D053148:Caspase 3 / Q000378:metabolism / Q000528:radiation effects; D002470:Cell Survival / Q000528:radiation effects; D002478:Cells, Cultured / Q000166:cytology / Q000201:enzymology / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005720:Gamma Rays; D006624:Hippocampus / Q000166:cytology / Q000201:enzymology / Q000528:radiation effects*; D011065:Poly(ADP-ribose) Polymerases / Q000187:drug effects / Q000235:genetics; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley
D011065:Poly(ADP-ribose) Polymerases; D053148:Caspase 3