Resveratrol Mitigates Rat Retinal Ischemic Injury: The Roles of Matrix Metalloproteinase-9, Inducible Nitric Oxide, and Heme Oxygenase-1

Purpose: Retinal ischemia-associated ocular disorders, such as retinal occlusive disorders, neovascular agerelated macular degeneration, proliferative diabetic retinopathy, and glaucoma are vision-threatening. In this study, we examined whether and by what mechanisms resveratrol, a polyphenol found in red wine, is able to protect against retinal ischemia/reperfusion injury. Methods: In vivo rat retinal ischemia was induced by high intraocular pressure (HIOP), namely, 120 mmHg for 60 min. The mechanism and management was evaluated by electroretinogram (ERG) b-wave amplitudes measurement, immunohistochemistry, and real-time polymerase chain reaction. Results: The HIOP-induced retinal ischemic changes were characterized by a decrease in ERG b-wave amplitudes, a loss of choline acetyltransferase immunolabeling of amacrine cell bodies/neuronal processes, and increased vimentin immunoreactivity, which is a marker of Muller cells, together with upregulation of matrix metalloproteinase-9 (MMP-9), heme oxygenase-1 (HO-1), and inducible nitric oxide (iNOS), and downregulation of Thy-1, both at the mRNA level. The detrimental effects due to the ischemia were concentration-dependent (weaker effect at 0.05 nmole) and/or significantly (at 0.5 nmole) altered when resveratrol was applied 15 min before or after retina ischemia. Conclusion: This study supports the hypothesis that resveratrol may be able to protect the retina against ischemia by downregulation of MMP-9 and iNOS, and upregulation of HO-1.