ASTROCYTES PROTECT AGAINST X-RAY-INDUCED NEURONAL TOXICITY IN-VITRO

THE role of neuronal damage in the radiation-induced CNS injury result ing from brain tumor therapy remains poorly understood. To begin to de fine the radioresponse of neurons, the survival of rat cortical neuron cultures was investigated. Neuronal survival was reduced by similar t o 40% 24-48 h after irradiation with 3.5 Gy. The addition of the free radical scavenger NAC after irradiation increased neuronal survival. N eurons were also significantly less sensitive to radiation in co-cultu res with astrocytes or in the presence of astrocyte-conditioned medium . Medium conditioned on astrocytes was found to acquire significant fr ee radical scavenging capability. However, this antioxidant property d oes not appear to be responsible for neuronal radioprotection. The abi lity of astrocytes to reduce radiation-induced neuronal toxicity appea rs to be mediated by a soluble protein(s) of mel. wt > 10 kDa. (C) 199 8 Rapid Science Ltd.