Abstract
Purpose :
The purpose of the present study was to determine whether the flavonoid, anthocyanin oligomers is effective at blunting the negative influence of ischemia/reperfusion to the rat retina in situ and of various insults to a retinal precursor cells (R28) in culture.
Methods :
R28 in culture were given one of three different insults, light (1000 lux for 2 days), hydrogen peroxide (200 µM H2O2 for 24 hours) or serum deprivation (48 hours). Cell survival and reactive oxygen species (ROS) formation was assayed. Lipid peroxidation assay was used to compare the antioxidant capacity of anthocyanin oligomers. In animal studies, anthocyanin oligomers was administered intraperitoneally just before and after an ischemic insult and ischemia was delivered by raising the intraocular pressure above the systolic blood pressure(50 min). Retinas were analysed for the localisation of various antigens and retinal extracts were also analysed for various mRNAs.
Results :
Ischemia/reperfusion to the retina affected the localisation of Thy-1 and choline acetyltransferase (ChAT) and the content of various proteins (optic nerve and retina) and mRNAs (retina). Importantly, anthocyanin Oligomers statistically blunted most of the effects induced by ischemia/reperfusion. Only the increase in caspase-8 caused by ischemia/reperfusion was unaffected by anthocyanin oligomers treatment. Anthocyanin oligomers also attenuated significantly the negative insult of light, hydrogen peroxide and serum withdrawal to R28 cells. In the lipid peroxidation studies, anthocyanin oligomers was also found to be equally effective as EGCG to act as an antioxidant. Significantly, the negative insult of serum withdrawal on R28 cell survival was blunted by anthocyanin oligomers but not by EGCG revealing the different properties of the two flavonoids.
Conclusions :
Our results demonstrate the powerful antioxidant characteristics of anthocyanin oligomers. Together with anti-apoptotic effects of anthocyanin oligomers suggest its potential use for the treatment of various ocular diseases such as glaucoma, where oxidative stress has been suggested to be involved in many aspects of pathogenesis.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.