Matrix metalloproteinase-9 expression in retinal ganglion cell layer and effect of topically applied brimonidine tartrate 0.2% therapy on this expression in an endothelin-1-induced optic nerve ischemia model

• Published in: International ophthalmology Vol. 30; no. 3; pp. 253 - 259
• Main Authors: Aktas, Zeynep, Gurelik, Gokhan, Göçün, Pınar Uyar, Akyürek, Nalan, Önol, Merih, Hasanreisoğlu, Berati
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-06-2010; Springer Nature B.V
• Subjects: Adrenergic alpha-Agonists - therapeutic use; Animals; Brimonidine Tartrate; Gene Expression Regulation, Enzymologic; In Situ Nick-End Labeling; Infusion Pumps; Intraocular Pressure - drug effects; Matrix Metalloproteinase 9 - genetics; Medicine; Medicine & Public Health; Ophthalmology; Optic Neuropathy, Ischemic - chemically induced; Optic Neuropathy, Ischemic - drug therapy; Original Paper; Quinoxalines - administration & dosage; Quinoxalines - therapeutic use; Rabbits; Retinal Ganglion Cells - drug effects; Retinal Ganglion Cells - enzymology; Matrix metalloproteinase-9; Brimonidine; Retinal ganglion cell layer; Endothelin-1
• ISSN: 0165-5701; 1573-2630
• DOI: 10.1007/s10792-009-9316-9

The purpose of this research is to investigate the expression of matrix metalloproteinase-9 (MMP-9) in retinal ganglion cells (RGC) and the impact of topically applied brimonidine tartrate 0.2% (BMD) on this expression in an endothelin-1 (ET-1)-induced chronic optic nerve (ON) ischemia model of rabbit. Osmotically driven minipumps were implanted in one eye of 16 New Zealand albino rabbits to deliver ET-1 at the constant rate of 0.5 μl/h for 2 weeks. ET-1 was given with (group 3) and without topical BMD therapy (group 1). Groups 2 and 4 were taken as controls. MMP-9 expression by immunohistochemically and proportion of cells undergoing apoptosis in RGC layer were investigated. The correlation between the MMP-9 immunopositivity and the proportion of cells undergoing apoptosis in the RGC layer was evaluated. MMP-9 immunopositivity was found to be significantly higher in both groups 1 and 3 compared to that of the controls. There was no difference between groups 1 and 3 regarding MMP-9 expression (
p
= 0.495). A positive correlation was found between the proportion of cells undergoing apoptosis and MMP-9 expressions in the RGC layer in group 1 (
p
= 0.031, r = 0.754). MMP-9 expression in the RGC layer seems to significantly increase in the ET-1-induced chronic ON ischemia model. Topical BMD therapy does not seem to affect this MMP-9 expression.