The effect of irradiation in air or in hyperbaric oxygen on the Fib/T tumor in WHT mice pretreated with a hypoxic gas mixture.
The effect of exposing WHT mice bearing the Fib/T tumor to a low-oxygen environment (8, 10, and 15% oxygen) for 48 h or 72 h before irradiation was compared, using an in vitro colony-forming excision assay, to the effect obtained when mice were pretreated with air. The response of the Fib/T tumor to radiation delivered in air was improved both by a 48-h and by a 72-h exposure of the animals to 8, 10, and 15% oxygen. However, the greatest tumor sensitization was achieved when mice were kept in 8% oxygen for 48 h before irradiation. These results are interpreted and discussed in relation to increases in the 2,3-DPG concentration, which were shown to occur when mice were exposed to a reduced oxygen environment. The relative importance of two models proposed to explain these findings is assessed. If mice pretreated with air were irradiated in hyperbaric oxygen, a similar tumor response was observed compared to that when mice were exposed to 8% oxygen for 48 h and then irradiated in air.
Hendrikse
A
A
Department of Radiotherapy, University of Cape Town, South Africa.
Blekkenhorst
G
G
D000388:Air; D000818:Animals; D002470:Cell Survival / Q000528:radiation effects; D003037:Cobalt Radioisotopes; D004163:Diphosphoglyceric Acids / Q000097:blood; D004307:Dose-Response Relationship, Radiation; D004912:Erythrocytes / Q000737:chemistry; D005720:Gamma Rays; D006931:Hyperbaric Oxygenation; D008297:Male; D051379:Mice; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental / Q000503:physiopathology / Q000532:radiotherapy*; D010100:Oxygen / Q000502:physiology*
D003037:Cobalt Radioisotopes; D004163:Diphosphoglyceric Acids; D010100:Oxygen