[Radiation vasculopathy--caused by a change in vascular prostacyclin synthesis?]

Earlier investigations revealed morphological damage of the vascular wall after radiotherapy. The present investigation was undertaken to determine whether vascular prostacyclin synthesis plays a causative role in the genesis of vasculopathy. Rabbits were exposed to a focal radiation dose of between 500 and 5000 rad over various time intervals. Vascular PGI2-synthesis increased significantly immediately after radiation, with a subsequent decrease over the following days to levels below the starting values. Each repeated radiation dose induced a significant increase in PGI2-synthesis again. These observations were paralleled by severe morphological alterations, mainly localized in endothelial cells and elastic material. The findings suggest that a deterioration in PGI2-synthesis plays a key role in the genesis of radiation-induced vasculopathy.