In vitro response of human and porcine vascular cells exposed to high dose-rate gamma-irradiation.
OBJECTIVE
The objective of this study was to compare the in vitro response of human and pig endothelial cells, smooth muscle cells and fibroblasts exposed to conventional high dose-rate gamma-irradiation.


METHODS
Clonogenic cell survival and growth responses were obtained after irradiation of plateau-phase cells with a 60Co source at a dose-rate of 1.5 Gy/min. DNA single-strand breaks were also evaluated using an alkaline filter elution technique.


RESULTS
Overall, both the pig and human cell lines showed a similar response to conventional high dose-rate irradiation. Using clonogenic assays, the human aortic smooth muscle cell line was more sensitive than the fibroblast and endothelial cell lines, whereas the pig endothelial cell line was more sensitive than smooth muscle cells and fibroblasts. Shortly after irradiation (10 days) there was a temporary growth arrest, which was similar for endothelial, smooth muscle cells and fibroblasts with doses above 6 Gy. There was also a non-linear, dose-dependent growth delay up to 4 weeks after irradiation. This effect was also consistent between the different cell lines. Using alkaline filter elution, there was no significant difference in relative elution between endothelial cells, smooth muscle cells and fibroblasts, indicating similar DNA damage among the different cell lines.


CONCLUSIONS
The in vitro response of human and pig endothelial cells, smooth muscle cells and fibroblasts exposed to high dose-rate irradiation appeared similar. The pig model seems well suited to evaluate the short- and long-term effects of ionizing radiation in the prevention of restenosis after vessel injury.
Bertrand
O F
OF
Division of Experimental Medicine, McGill University, Montreal, Canada. ofbert@icm.umontreal.ca
Mongrain
R
R
Thorin
E
E
Lehnert
S
S
D000328:Adult; D000818:Animals; D002470:Cell Survival / Q000528:radiation effects; D002675:Child, Preschool; D004249:DNA Damage; D004730:Endothelium, Vascular / Q000166:cytology / Q000528:radiation effects*; D005347:Fibroblasts / Q000528:radiation effects; D005720:Gamma Rays; D006801:Humans; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000528:radiation effects*; D011829:Radiation Dosage; D013552:Swine