Effect of docosahexaenoic acid intake on lipid peroxidation in diabetic rat retina under oxidative stress

Docosahexaenoic acid (DHA) plays an important role in visual function but has a highly oxidation-prone chemical structure. Therefore, we investigated how dietary DHA affects the generation of lipid peroxides in rat retina under oxidative stress in diabetes with/without vitamin E (VE) deficiency. Streptozotocin-induced (50 mg i.p./kg B.W.) diabetic Sprague-Dawley (SD) rats were assigned to four groups: (i) control/VE(+), (ii) DHA/VE(+), (iii) control/VE( - ) and (iv) DHA/VE( - ), and raised for 28 days. We then measured lipid peroxide levels in the retina, serum and liver. With a normal intake of VE, dietary DHA increased only the retinal level of thiobarbituric acid-reactive substances (TBARS) slightly. In contrast, in rats with VE deficiency, dietary DHA increased serum and liver lipid peroxide levels but not in the retina. These results suggest that dietary DHA does not necessarily promote lipid peroxidation in the retina even under high oxidative stress.