Early effects of PRS-irradiation for 9L gliosarcoma: characterization of interphase cell death.
We characterized the interphase cell death of 9L gliosarcoma after high-dose-rate, low-energy photon irradiation using the Photon Radiosurgery System (PRS), a novel device for interstitial radiotherapy. Within 24 hours after irradiation with a dose of 18 Gray, 22.0% of cells underwent metabolic cell death, whereas dead cells in controls stayed less than 5.0% (p<0.005). In the majority of sensitive cells, loss of membrane integrity preceded the lethal morphological changes. The response was dose-dependent over the range of 9-18 Gray, but saturation was obtained over 18 Gray. On the other hand, a significant (p < 0.01) increase in the number of TUNEL-positive cells with apoptotic morphology was detected 6-24 hours after irradiation, but the fraction remained 1.9-2.1% of the population and was independent of the doses between 9 and 25 Gray. Apoptotic cells were rarely observed in the control cells (0.3-0.6%). Our data indicate that single high-dose irradiation induces both necrotic and apoptotic interphase cell death in 9L gliosarcoma, but rapid cell death mostly occurs through the non-apoptotic pathway.
Department of Stereotactic Neurosurgery, Albert-Ludwigs-University of Freiburg, Germany.
H
H
Kurita
C B
CB
Ostertag
B
B
Baumer
K
K
Kopitzki
P C
PC
Warnke
D017209:Apoptosis / Q000528:radiation effects; D001918:Brachytherapy; D001932:Brain Neoplasms / Q000532:radiotherapy*; D002470:Cell Survival / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D018316:Gliosarcoma / Q000532:radiotherapy*; D006801:Humans; D007399:Interphase / Q000528:radiation effects; D009336:Necrosis; D016634:Radiosurgery; D014407:Tumor Cells, Cultured / Q000528:radiation effects*