Protection of iodine-125 brachytherapy brain injury in the rat with the 21-aminosteroid U-74389F.
Radiation protection was studied in a rat brachytherapy brain injury model. Radiation lesions were produced by stereotactic placement of high-activity iodine-125 seeds on the frontal lobe of F-344 rats. A minimum dose of 80 Gy was delivered to a 5.5-mm-radius volume. Radiation damage was evaluated 24 h after removal of the seeds by T1-weighted gadolinium-enhanced magnetic resonance imaging on a 1.5-T unit. Computerized three-dimensional reconstruction of the lesions seen on magnetic resonance imaging was performed to calculate the volume of radiation injury. Two experiments were performed with rats of different weights (mean, 300 g; mean, 180 g). All animals underwent surgical placement of an indwelling internal jugular catheter before brachytherapy. Treated animals received the 21-aminosteroid U-74389F 5 mg/kg intravenously every 6 hours during the implant and for 24 hours after the removal of the iodine-125 seed. Control animals were administered vehicle only. In both experiments, a statistically significant reduction in volume of radiation damage was observed in the U-74389F-treated group compared with the control group.
Bernstein
M
M
Brain Tumor Research Laboratory, Toronto Hospital-Toronto Western Division, University of Toronto, Ontario, Canada.
Ginsberg
H
H
Glen
J
J
D000818:Animals; D001918:Brachytherapy / Q000009:adverse effects*; D001921:Brain / Q000473:pathology / Q000528:radiation effects*; D004305:Dose-Response Relationship, Drug; D007457:Iodine Radioisotopes / Q000009:adverse effects*; D008279:Magnetic Resonance Imaging; D008297:Male; D011281:Pregnatrienes / Q000494:pharmacology*; D011833:Radiation Injuries, Experimental / Q000473:pathology*; D011837:Radiation-Protective Agents / Q000494:pharmacology*; D051381:Rats; D011916:Rats, Inbred F344
D007457:Iodine Radioisotopes; D011281:Pregnatrienes; D011837:Radiation-Protective Agents; C074965:U 74389F