title: Cell cycle changes and cytotoxicity in irradiated cultures of bovine aortic endothelial cells.
abstract: The purpose of this experiment was to determine the effect of ionizing radiation on cell number, lactate dehydrogenase (LDH) release, cell cycle distribution, [3H]thymidine incorporation, and autoradiographic labeling index in bovine aortic endothelial cells in vitro. Confluent endothelial monolayers were exposed to single doses of 0.5-10 Gy of 60Co gamma rays and were analyzed from 2 to 24 h postirradiation. Irradiated monolayers exhibited a time- and dose-dependent decrease in cell number, increase in LDH release, and redistribution of cells in the cell cycle. Cell cycle redistribution included an increase in the proportion of cells in S phase at 4 h after irradiation and a decrease in S phase at 24 h. The cells also exhibited a decrease in [3H]thymidine incorporation as early as 2 h after 5 Gy. This represented the most rapid radiation response observed in the present study. These data demonstrate that radiation cytotoxicity in confluent, plateau-phase endothelial monolayers is accompanied by changes in the cell cycle distribution of adherent cells, and that reduced [3H]thymidine incorporation is an early marker of radiation injury in this clinically important cell type.
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000166:cytology / Q000528:radiation effects; D002417:Cattle; D002453:Cell Cycle / Q000528:radiation effects*; D004247:DNA / Q000096:biosynthesis; D004727:Endothelium / Q000378:metabolism / Q000528:radiation effects*; D066298:In Vitro Techniques; D007770:L-Lactate Dehydrogenase / Q000378:metabolism
chemical_list: D004247:DNA; D007770:L-Lactate Dehydrogenase