title: Radiation inhibition of intimal hyperplasia after arterial injury.
abstract: To demonstrate the effect of gamma radiation on proliferating smooth muscle cells in vivo, a standardized bilateral carotid balloon catheter arterial injury was produced in 45 rats and doses from 0-20 Gy were delivered to the right carotid artery at 24 h after injury. At 20 days after injury, cross-sectional area of intima was determined from axial histological sections. Compared to contralateral, nonirradiated balloon-injured arteries, radiation produced a significant dose-dependent reduction in intimal cross-sectional area, with a 50% decrease at 5-7.5 Gy. To determine the effect of timing of irradiation on intimal hyperplasia, 30 rats with bilateral carotid injury received unilateral cervical irradiation at doses of 1, 5 or 10 Gy administered at either 1, 3 or 5 days after injury. The radiation dose (P = 0.0002), timing of irradiation (P = 0.003) and an interaction between timing and dose (P = 0.0278) were significantly associated with reduction in neointimal cross-sectional area. To determine the effects of radiation on intimal hyperplasia at later intervals, rats irradiated with 15 (n = 5) or 20 Gy (n = 5) were euthanized at 3 months after injury. A significant persistent reduction in intimal cross-sectional area for irradiated arteries at 3 months was associated with minimal apparent radiation effects upon adjacent tissue. These data suggest that external gamma irradiation at the single doses used effectively inhibits smooth muscle proliferation and intimal hyperplasia in the rat balloon catheter injury model in a time- and dose-dependent manner.
authors.affiliation: Department of Neurological Surgery, University of Washington, Seattle 98195, USA.
authors.forename: M R
authors.initials: MR
authors.lastname: Mayberg
authors.forename: Z
authors.initials: Z
authors.lastname: Luo
authors.forename: S
authors.initials: S
authors.lastname: London
authors.forename: C
authors.initials: C
authors.lastname: Gajdusek
authors.forename: J S
authors.initials: JS
authors.lastname: Rasey
mesh_terms: D000800:Angioplasty, Balloon / Q000009:adverse effects; D000818:Animals; D002339:Carotid Arteries / Q000473:pathology / Q000528:radiation effects; D002465:Cell Movement; D004307:Dose-Response Relationship, Radiation; D006965:Hyperplasia; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000473:pathology / Q000528:radiation effects*; D011833:Radiation Injuries, Experimental / Q000209:etiology; D051381:Rats; D017207:Rats, Sprague-Dawley