Abstract
Purpose: :
The study was to investigate the effects of hydrogen peroxide (H2O2) on retinal function from isolated rat retina and evaluate the H2O2-induced oxidative stress.
Methods: :
Retinas were isolated from rat eyes and placed in a chamber continuously perfused with a nutrient solution. The ERG was recorded every 3 minutes. Once the ERG was at a steady state, H2O2 was added at various concentrations (0.1-1mM) to the perfusion medium for 3 hours. The amplitudes and implicit times of the b-, a- and PIII-waves vs. time were plotted to obtain ‘the survival curves’. The malondialdehyde (MDA) content in perfusion medium was evaluated by HPLC as a biomarker for oxidative stress.
Results: :
Application of H2O2 on isolated retinas produced a rapid increase in the b-wave amplitude followed by a significant decrease, as compared to the unexposed retinas. The amplitudes of the a- and PIII-wave decreased significantly. The implicit time of the a-wave remained unchanged; the implicit time of the b-wave showed a moderate increase and then returned to its normal value; whereas the implicit time of the PIII-wave increased significantly and then returned to its normal value. The H2O2-associated changes of the ERG amplitudes and implicit times were dose dependent. The content of MDA in perfusion medium increased in a dose dependent manner.
Conclusions: :
Exposure of retina to H2O2 impairs retinal function as shown by the changes of the ERG amplitudes and implicit times, and induces oxidative stress as reflected by the increase of MDA.
Keywords: retina • oxidation/oxidative or free radical damage • electroretinography: non-clinical