Abstract
Purpose: :
Lipid oxidation has been proposed to be a factor in the pathophysiology of glaucoma. We investigated whether elevated levels of isolevuglandin (iso[4]LGE2) protein adducts are associated with astrocytes derived from glaucomatous optic nerve head. In addition, how iso[4]LGE2 protein adducts are altered following exposure of astrocytes to ambient and elevated pressure was examined.
Methods: :
Astrocytes were isolated from rat brain cortex and human optic nerve, and subjected to pressure treatments, Western blot analyses, liquid chromatography tandem mass spectrometry and immunocytochemistry.
Results: :
Elevated levels of isolevuglandin (iso[4]LGE2) protein adducts were associated with astrocytes derived from glaucomatous optic nerve head compared to those from controls. Astrocytes subjected to in vitro pressure treatment results in increased levels of iso[4]LGE2 protein adducts. Pressure exposure and recovery period affects iso[4]LGE2 protein modification and pyridoxamine incubation results in decreased iso[4]LGE2 protein adduct immunoreactivity when applied immediately after pressure treatment.
Conclusions: :
These results suggest that the elevated iso[4]LGE2 protein adduct immunoreactivity observed in glaucomatous astrocytes may be due to chronic and/or prolonged exposure to pressure.
Keywords: astrocyte • protein modifications-post translational • intraocular pressure