Abstract
Abstract: :
Purpose: To investigate the change of vitamin E (VE) and reduced form vitamin C (VC) and glutathione (GSH) contents in retinal tissue following exposure to linoleic acid hydroperoxide (LHP). Methods: Zero point six mg of LHP dissolved in 100 µL of borate buffer was injected into the vitreous of anesthetized male, New Zealand white rabbits, using a 30 gauge needle. Animals were sacrificed and the eyes were enucleated at 1, 3, 6, 12, 24 hr, and at 4 and 7days. The concentration of VE and VC were determined by HPLC, and of GSH was determined by a fluorometric method. Results: VC decreased at 6 hrs (2.74±0.16nmol/g of tissue, n=3) and returned to pretreatment levels at 24 hr after the injection. VE also decreased and was lowest peak at 6 hr (6.11±1.80×10–8mol/g of tissue, n=4), then increased gradually and returned to pretreatment levels by 7 days. GSH decreased and was lowest peak at 12 hr (72.40±11.17µg/g, n=5,p<0.05), then returned to pretreatment levels by 7 days. Conclusions: The antioxidant capacity of both water and lipid soluble compounds in retina is transiently compromised by intravitreal LHP which may damage them by free radical attack. During this period of low activity, LHP is unchecked and can stimulate transcription and activation of angiogenic cytokine as previously reported by us for this neovascular model. These results suggest that VE, VC and GSH play important roles in protecting the retina from oxidative stress in a time dependent manner.
Keywords: oxidation/oxidative or free radical damage • antioxidants • retina