Abstract
Purpose:
To investigate the effect of a renin inhibitor against retinal ischemia-reperfusion injury.
Methods:
Retinal ischemia was induced by increasing intraocular pressure to 130 mmHg for 45 min. Rats were treated with a renin inhibitor (aliskiren). 25 mg/kg/day aliskiren or vehicle was administered by subcutaneous osmotic minipump 1 day before ischemia. At 7 days after ischemia, retinal damage was evaluated by measuring the retinal thickness and the number of retinal ganglion cells. Western blot was used to measure changes in the (pro)renin receptor expression. Data were analyzed using an independent Student’s t-test or Dunnett’s multiple comparison test.
Results:
Retinal ganglion cell survival rates in the retinas with ischemia were 47.0% ± 5.7% in the vehicle-treated group and 102.3% ± 4.3% in the aliskiren-treated group (P < 0.001). In animals pretreated with distilled water, inner plexiform layer (IPL) and inner nuclear layer (INL) thicknesses were reduced to 64.8% ± 2.9% and 79.0% ± 3.3% of the control, respectively. When animals were pretreated with aliskiren, the IPL and INL thicknesses were 96.3% ± 1.0% (P < 0.001) and 102.3% ± 1.5% (P < 0.001) of the control, respectively. Although expression of (pro)renin receptor in the retina was similar between samples for the controls and after the reperfusion, (pro)renin receptor expression was decreased after reperfusion in the aliskiren-treated group.
Conclusions:
Aliskiren may protect neurons by decreasing the expression of (pro)renin receptor after ischemia-reperfusion.
Keywords: 572 ischemia •
615 neuroprotection