.1 Radiation Brain Injury In Animal Models And Early Detection And Prevention. A New Radiobiology Death - Survival Of The Theoretical Study Of The Model

Objective: To develop a mouse model of radiation-induced brain injury (RIBI), and then study the effects of the traditional medical blood-activator (TMBA) and cinnarizine (CA) in treating RIBI using this model. In additional, a clinical trial was designed to study the relationships of memory loss and brain injury in long-term survivors of nasopharyngeal carcinoma (NPC) after radiotherapy.Materials and Methods: 2 week-aged Chunking mice were irradiated with 10MeE electrons. The radiation portal included neck, neck with part brain and whole brain, and the dose was 30, 25 and 20 Gys in single irradiation, respectively. Step down and water waze test were used to examine the brain function at 2^nd, 4^th, 6^th, 8^th weekend after irradiation, while the pathological studies of the neck soft tissue and brain were completed. The irradiated mice were treated with the traditional medical blood-activator (24mg/Kg) and cinnarizine (27mg/Kg). In clinical study, Memory test was examined in 24 long-term NPC survivors and 30 normal people, while CT (or MRI) of brain was used for every NPC survivors to detect brain morphological injury.Result: (1) The indexes of step down and water waze were higher in irradiated mice than the controls (p<0.05). (2) The indexes of step down and water waze in the treated groups were slighter than untreated groups (p<0.05), but were higher than the unirradiated groups (p<0.05). (3) The peak of acute radiation injury in neck soft tissue and brain was in the 2nd weekend. The neck soft tissue and brain were normal at 8th weekend after radiation except some slight fibrosis in neck soft tissue. It showed some deviated trend between the brain functional test and pathological studies at 6th and 8th weekend after irradiation. (4) The acute radiation injury of neck soft tissue and brain were slighter in treated groups than in untreated groups. (5) The extent of memory loss was in direct proportion to the survival time (r = -0.72, p<0.001) and the degree of late brain injury in long-term NPC survivors.Conclusion: (1) The loss of brain was an early index of RIBI in mouse model. (2) The TMBA and CA could mitigate the radiation-induced brain injury. (3) Memory test might be a valuable tool to early diagnose serious brain injury in long-term survivors of NPC after radiotherapy.