Figure 5.

Effect of thoracic irradiation and captopril therapy on peripheral pulmonary arterial density index. Values (mean±sem) measured at 2-months after radiation exposure using high-magnification planar angiography of distal portions of the intact, contrast filled arterial tree in isolated lung preparations. Drug therapy groups received captopril (17 or 56 mg/kg/d) immediately or delayed 2 weeks after irradiation. Irradiation caused a decrease in peripheral arterial density. The vasoactive dose of captopril (56mg/kg/d) increased peripheral arterial density compared to irradiated, untreated rats. Vessel densities after irradiation and therapy with a vasoactive dose of captopril (immediate or delayed) were no different from values in unirradiated controls. (Number of rats in individual groups indicated on the bars, * p ≤ 0.026, ^ p ≤ 0.046, difference from bold marker).