Effects of Angiotensin II on Glomerular Epithelial Cells Permeability Model; Role of Oxidative Stress / 대한신장학회잡지

ABSTRACT

BACKGROUND: Glomerular injury induced by angiotensin II (Ang II) may arise from its hemodynamic or non-hemodynamic actions including oxidative stress, or from such effects of Ang II acting in concert. The release of reactive oxygen species from podocytes may play a role in the pathogenesis of glomerular damage and proteinuria. METHODS: To investigate whether Ang II induces oxidative stress in vitro in glomerular epithelial cells (GEpC) and whether such oxidant stress may increase in vitro glomerular permeability model using cultured GEpC, we studied GEpC culture exposed to Ang II and antioxidant, probucol. For oxidative system assay, we measured the production of superoxide anion and hydrogen peroxide and the activity of superoxide dismutase (SOD). Scanning electron microscopy was performed on cells grown for one week on chamber slides. RESULTS: We found that in vitro permeability, which was prevented from probucol, increased significantly in media with 10-4 and 10-5 M of Ang II by 15.9% and 13%, respectively. Administration of the 10-5 M of Ang II significantly increased the superoxide anion productions by 39%, 61% and 30% at 1, 2 and 6 hours exposure time, respectively, compared to those of control and suppressed by probucol to control levels. At high concentration (10-5 M) Ang II suppressed the activity of SOD without affecting the production of hydrogen peroxide on the other hand, at low concentration (less than 10-5 M) Ang II showed reverse results. On ultrastructural examination, we could see the shortened and fused microvilli on GEpC surface by 10-5 M of Ang II, which change could be prevented by probucol. CONCLUSION: We could suggest that Ang II induces the generation of superoxide anion and the suppression of the activity of SOD, and subsequent oxidative stress leading to increase glomerular permeability by disruption of glomerular filtration barrier.