Thymocyte apoptosis in response to low-dose radiation.
Thymocyte apoptosis was assessed by counting apoptotic bodies with flow cytometry (FCM) and measuring DNA fragmentation with fluorescence spectrophotometry (FSP). J-shaped dose-response curves were obtained after both whole-body irradiation (WBI) of mice and in vitro irradiation of EL4 cells with doses ranging from 0.025 to 4 Gy X-rays. There was a significant reduction of apoptosis rate to below control level with doses within 0.2 Gy, and a dose-dependent increase in apoptosis with doses above 0.5 Gy. When thymocytes were cultured 24 h after WBI with 75 mGy X-rays in complete RPMI 1640 medium, a reduction in apoptosis was observed in the course of incubation for 72 h, and the presence of Con A in the medium accentuated this reduction in a dose- and time-dependent manner. The implications of these observations and the possible molecular mechanisms for future studies are proposed.
Liu
S Z
SZ
MPH Radiobiology Research Unit, PRC, Norman Bethune University of Medical Sciences, Changchun, China.
Zhang
Y C
YC
Mu
Y
Y
Su
X
X
Liu
J X
JX
D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects*; D002453:Cell Cycle / Q000528:radiation effects; D002478:Cells, Cultured; D003208:Concanavalin A / Q000494:pharmacology; D004307:Dose-Response Relationship, Radiation; D008223:Lymphoma / Q000473:pathology / Q000532:radiotherapy; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D013950:Thymus Gland / Q000166:cytology / Q000187:drug effects / Q000528:radiation effects*; D014407:Tumor Cells, Cultured; D014916:Whole-Body Irradiation; D014965:X-Rays
D003208:Concanavalin A