Abstract
Introduction: :
Objective: A novel mitochondrial ATP-binding cassette transporter (ABC-me) protein has been shown to protect against oxidative stress. Although ABC-me expression has been indentified in various tissues it is currently unknown whether ABC-me is expressed in the retina. The aim of the study is to determine whether ABC-me is expressed in retinal endothelial cells (RRECs), and whether high glucose alters ABC-me expression in these cells.
Methods: :
To determine the effect of high glucose on ABC-me expression, rat retinal endothelial cells (RRECs) were grown in normal (5mM) glucose or high (30mM) glucose medium for 7 days. At the end of this period, cells were harvested, protein was isolated, and Western blot analysis performed using rabbit ABC-me primary antibody. After transfer of proteins, the membrane was stained with Ponceau-S and the densitometric values used for correcting protein amounts loaded in the gel lanes. To determine the presence of ABC-me in the retina, protein from Sprague Dawley rat retinas were subjected to Western blot analysis using the ABC-me antibody.
Results: :
Western blot analysis showed that the RRECs express ABC-me protein. Similarly, Western blot analysis also showed that cells grown in high glucose medium exhibit significant inhibition of ABC-me protein levels by approximately 25% compared to those of cells grown in normal medium. In addition, the presence of ABC-me expression in the rat retina was confirmed by Western blot analysis.
Conclusions: :
This study provides the first evidence of ABC-me protein expression in the retina, and in the retinal endothelial cells in culture, and that high glucose downregulates ABC-me expression. Since ABC-me is protective against oxidative stress, high glucose induced inhibition of ABC-me expression may contribute to mitochondrial dysfunction in diabetic retinopathy.
Keywords: diabetic retinopathy • mitochondria