Abstract
Purpose: :
To determine whether resveratrol, a polyphenol derived from purple grapes, induces anti-aging protein Sirt1 and Ku70 proteins in the retina, and provides protection against anti-recoverin-antibody-induced apoptosis in the rat model of autoimmune and paraneoplastic retinopathies.
Methods: :
SD rats were treated with resveratrol and anti-recoverin antibody as follows: group 1 received 30 µg of anti-recoverin Ab to the left eye and vehicle to the right eye; group 2 received 30 µg of anti-recoverin antibody to the left eye, vehicle to the right eye, and four daily doses of 125 mg/kg of resveratrol intraperitoneally beginning the day of antibody injection; and control group 3 received 5 µl vehicle intravitreously to the left eye. One week after the antibody injection, eyes were collected, fixed, and cryosectioned. The expression of Sirt1 and Ku70 was examined by immunofluorescent staining. Specific retinal cells were identified by the application of anti-rhodopsin antibody (R2-12N) for photoreceptors, anti-PKCα for bipolar cells, and anti-calbindin for horizontal cells in immunofluorescence staining.
Results: :
Eyes from rats receiving resveratrol, irrespective of intravitreal anti-recoverin antibody injection, showed a strong immunostaining of Sirt1 in the outer and inner segments of photoreceptor cells, and also in horizontal cells, bipolar cells, and ganglion cells. In the control groups not treated with resveratrol, these retinal cells were only weakly stained for Sirt1. Immunofluorescence pattern of Ku70 expression in resveratrol-treated rats was similar to Sirt1 with similar localization in the retinal cells, particularly in the outer and inner segments.
Conclusions: :
An increased expression of anti-aging protein Sirt1 in the retinas of resveratrol treated rats suggests the role of resveratrol in protection from apoptosis induced by anti-recoverin antibody. Cellular co-localization of Sirt1 with anti-apoptotic Ku70 in the photoreceptor cells, the target site of anti-recoverin antibody, further provides evidence for the mechanism of retinal protection.
Keywords: autoimmune disease • retina • antioxidants