Relative biological effectiveness (RBE) of alpha radiation in cultured porcine aortic endothelial cells.
OBJECTIVE
Northern peoples can receive elevated radiation doses (1- 10 mSv/y) from transfer of polonium-210 (210Po) through the lichen-caribou-human food chain. Ingested 210Po is primarily blood-borne and thus many of its short range alpha particles irradiate the endothelial cells lining the blood vessels. The relative biological effectiveness (RBE) of alpha particles vs. x-rays was examined in porcine aortic endothelial cells as a surrogate for understanding what might happen to human endothelial cells in northern populations consuming traditional foods.


METHODS
Cultured porcine aortic endothelial cells were exposed to x-ray and 210Po alpha particle radiation. Alpha irradiation was applied to the cell cultures internally via the culture medium and externally, using thin-bottomed culture dishes. The results given here are based on the external irradiation method, which was found to be more reliable. Dose-response curves were compared for four lethal endpoints (cell viability, live cell fraction, release of lactate dehydrogenase [LDH] and clonogenic survival) to determine the relative biological effectiveness (RBE) of alpha radiation.


RESULTS
The alpha RBE for porcine cells varied from 1.6-21, depending on the endpoint: 21.2+/-4.5 for cell viability, 12.9+/-2.7 for decrease in live cell number, 5.3+/-0.4 for LDH release to the medium but only 1.6 +/-0.1 for clonogenic survival. The low RBE of 1.6 was due to x-ray hypersensitivity of endothelial cells at low doses.
Thomas
Patricia
P
Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan.
Tracy
Bliss
B
Ping
Tilly
T
Baweja
Anar
A
Wickstrom
Mark
M
Sidhu
Narinder
N
Hiebert
Linda
L
D000512:Alpha Particles; D000818:Animals; D001011:Aorta / Q000166:cytology / Q000378:metabolism / Q000528:radiation effects*; D002470:Cell Survival / Q000528:radiation effects; D002478:Cells, Cultured; D004307:Dose-Response Relationship, Radiation; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism / Q000528:radiation effects*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008954:Models, Biological; D012062:Relative Biological Effectiveness; D013552:Swine; D014965:X-Rays
D007770:L-Lactate Dehydrogenase