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

Int Ophthalmol. 2010 Jun;30(3):253-9. doi: 10.1007/s10792-009-9316-9. Epub 2009 Jul 21.


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 microl/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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 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*
  • Optic Neuropathy, Ischemic / chemically induced*
  • Optic Neuropathy, Ischemic / drug therapy*
  • Quinoxalines / administration & dosage
  • Quinoxalines / therapeutic use*
  • Rabbits
  • Retinal Ganglion Cells / drug effects
  • Retinal Ganglion Cells / enzymology*


  • Adrenergic alpha-Agonists
  • Quinoxalines
  • Brimonidine Tartrate
  • Matrix Metalloproteinase 9