| Summary: | 碩士 === 國立陽明大學 === 藥理學研究所 === 97 === Ischemia plays an important role in glaucoma and retinal vascular occlusion, which renders investigation vital. Retinal ischemia was induced by raising intraocular pressure to 120 mmHg. Its management and mechanism was evaluated by measuring electroretinogram (ERG) b-wave amplitudes, the amounts of reactive oxygen species (ROS), choline acetyltransferase (ChAT) immunoreactivity, and the mRNA levels of matrix metalloproteinase-9 (MMP-9), and Thy-1. Sixty minutes of ischemia plus reperfusion resulted in retinal changes characterized by decreased ERG b-wave amplitudes, loss of choline acetyltransferase (ChAT) immunolabeled amacrine cell bodies/neuronal processes, and down-regulated Thy-1 m-RNA levels (indexing retinal ganglion cells, RGCs). Of clinical importance, this is the first study showing that ischemic detrimental effects are dose-dependently (with the less effect at 10 μM) and significantly (at 100 μM) blunted when baicalein was applied 15 minutes before retinal ischemia. Moreover, the 60-minute ischemia plus 12 or 24 hours of reperfusion induced significant up-regulated MMP-9 mRNA levels. The former effect was further significantly attenuated by pre-administered baicalein (100 μM). The dichlorofluorescein assay results show that pre-treated 100 μM baicalein can significantly attenuate the significant increased levels of ROS in the retina exposed to an oxidative stress. Conclusively, baicalein protects against retinal ischemia and possibly glaucoma by, at least in part, attenuating I/R-induced MMP-9 mRNA up-regulation, possibly related to an oxidative stress.
|
|---|
