RESUMO
The ability of the radioprotector gammaphos to modify the development of late vascular changes in rat brain after local irradiation with 25 Gy was investigated by means of angiographic method. A protective effect was seen against late vascular abnormalities. It is suggested that a causative relationship exists between vascular abnormalities, brain necrosis, and radiation mortality after irradiation with moderate doses.
Assuntos
Amifostina/uso terapêutico , Encéfalo/irrigação sanguínea , Microcirculação/efeitos da radiação , Compostos Organotiofosforados/uso terapêutico , Lesões Experimentais por Radiação/prevenção & controle , Protetores contra Radiação/uso terapêutico , Animais , Encéfalo/efeitos da radiação , Microcirculação/efeitos dos fármacos , Ratos , Ratos Endogâmicos , Fatores de TempoRESUMO
The ability of a radioprotector-gammaphos to modify the development of late vascular changes in the rat brain after local irradiation with 40 and 60 Gy was investigated by means of an angiographic method. The relative number of animals with gross vascular abnormalities, the size of foci with vascular lesions, and the changes in size and number of vessels were less in the drug-treated groups. Thus, it may be possible to increase the tolerance of host tissues to curative radiation therapy by chemical radioprotectors such as gammaphos.
Assuntos
Amifostina/farmacologia , Encéfalo/irrigação sanguínea , Compostos Organotiofosforados/farmacologia , Lesões Experimentais por Radiação/prevenção & controle , Animais , Relação Dose-Resposta à Radiação , Microcirculação/efeitos dos fármacos , Microcirculação/efeitos da radiação , Lesões Experimentais por Radiação/fisiopatologia , Ratos , Ratos Endogâmicos , Fatores de TempoRESUMO
The dynamics of the endothelial cell population was investigated in the rat brain after local irradiation with different doses of X rays. A fluorescent-histochemical technique was used for the visualization of the cells. A decrease in endothelial cell number was observed within 1 day of irradiation with doses of 5-200 Gy. At this time the endothelial cell number had decreased by up to 15% compared with the pre-treatment values. This early dose-independent loss in cell number was maintained for up to 1 month after irradiation. This was then followed by a slow dose-independent decrease in cell density up to 6 months after exposure. Subsequently the depletion of the endothelial cell population exposed to 40 and 60 Gy continued. After a dose of 25 Gy an abortive recovery of cell numbers occurred followed by an abrupt depletion of the endothelial cell population. The possible mechanisms of such changes are discussed.