Abstract
Purpose: :
To investigate the effect of angiotensin-converting enzyme inhibitor (ACEI) and angiotensin II (AT) receptor blocker against ischemia reperfusion injury in the rat retina.
Methods: :
Retinal ischemia was induced by increasing intraocular pressure to 130 mm Hg and maintaining that level for 45 minutes. Morphometric studies were performed to study the effect of captopril (ACEI), candesartan (AT type 1 receptor blocker), PD123319 (AT type 2 receptor blocker), and icatibant (bradykinin B2 receptor blocker) on the histological changes in the rat retina induced by ischemia. Retinal localization of AT type 1 receptor was examined by immunohistochemistry.
Results: :
Seven days after the ischemia, significant reductions in the thickness of the inner plexiform layer (IPL) were observed (57%). Pretreatment with captopril or candesartan significantly reduced in the thickness of IPL to 90% or 80 % of control, respectively (P < 0.05, unpaired t-test). In control retinas, retinal vessels were positive for AT type 1 receptor. In contrast, 12 hours after ischemia, immunohistochemical analysis showed many AT type 1 receptor-positive cells in the inner retina in vehicle-treated rat.
Conclusions: :
These results suggest that ACEI/AT type 1 receptor blocker may protect neurons against ischemia-induced damage.
Keywords: neuroprotection • ischemia • receptors: pharmacology/physiology