Functional and morphological damage of endothelium in rabbit ear artery following irradiation with cobalt60

摘要: The relaxant actions of acetylcholine and A23187 were examined in the rabbit central ear artery at different intervals following exposure to doses radiation with a cobalt60 unit. was irradiated dose 10 Gy, 20 Gy 45 Gy. Radiation caused dose- time-dependent impairment endothelium-dependent relaxations. impaired relaxations occurred as early 1 week postirradiation persisted throughout experimental period (10 weeks). The endothelium-independent response sodium nitroprusside well preserved up 6 weeks after irradiation. contractile noradrenaline unaltered by irradiation period, but contrast control vessels, an increase sensitivity presence nitric oxide synthase (NOS) inhibitor NG-nitro-L-arginine not observed vessels. The vessels improved pretreatment NOS substrate L-arginine, cyclo-oxygenase indomethacin or free radical scavengers superoxide dismutase catalase. Scanning electron microscopy indicated morphologically intact endothelial cells within first 4 irradiation. Western blot analysis showed significant decrease expression (eNOS) vessels. These data indicate that cell function is specifically before morphological damage can be detected. This may related diminished eNOS expression. British Journal Pharmacology (1998) 123, 653–660; doi:10.1038/sj.bjp.0701654