Abstract
Purpose: :
Oxidative stress is likely to have a role in the development and progression of age-related pathologies like glaucoma and in particular have effects in hypoxic micro-environments such as that of the lamina cribrosa (LC) region of the optic nerve head (ONH). The purpose of this study was to compare levels of oxidative stress and anti-oxidant enzymes in lamina cribrosa cells from normal (NLC) and glaucomatous (GLC) donor eyes.
Methods: :
Intracellular reactive oxygen species (ROS) levels were examined by a thiobarbituric acid reactive substances (TBARS) assay measuring malondialdehyde (MDA) production, a naturally occurring product of lipid peroxidation. Mitochondrial membrane potential (MMP) was evaluated using the fluorescent probe JC-1 by flow cytometry and confocal microscopy. DNA microarray analysis was used to determine expression levels of several anti-oxidant enzymes.
Results: :
Intracellular ROS levels were increased in GLC compared to NLC (27.19 ± 7.05 µM MDA vs 14.59 ± 0.82 µM MDA P<0.05). MMP was reduced in GLC (57.5 +/- 6.8%) compared to NLC (41.8 +/- 5.3%) as determined by flow cytometry and confocal microscopy. DNA microarray analysis revealed significantly reduced (P<0.05) antioxidant enzyme levels in GLC cells evidenced by relatively low expression of AKR1C1, GCLC, SOD1 and NFKB-2 compared to NLC.
Conclusions: :
These data are supportive of elevated cellular ROS and reduced anti-oxidant capacity being characteristic of lamina cribrosa cells derived from donors with glaucoma. The persistence of this phenomenon in vitro is suggestive of oxidative stress as being of importance in ONH remodelling in glaucoma. Potential future anti-glaucoma strategies may endeavour to reduce oxidative stress in the LC region of the ONH.
Keywords: lamina cribrosa • antioxidants • oxidation/oxidative or free radical damage