Abstract
Purpose: :
Dyslipidemia is a major complication of diabetes mellitus. While markers of dyslipidemia have been associated with diabetic retinopathy, little is known about retinal lipid metabolism in the onset and progression of diabetes. Docosahexaenoic acid (DHA 22:6n3) is the most abundant fatty acid in the retina, and deficiency of DHA has been linked to numerous retinal diseases. Our goal was to assess total retina DHA levels in a rat model of Type I diabetes and determine the detailed structural composition and abundance of DHA-containing lipid species.
Methods: :
STZ-injected male Wistar rat model of Type I diabetes was used. Rats were maintained on control or DHA enriched diets for 9 weeks. Saponified rat retinal fatty acids were analyzed by HPLC. Shotgun nESI MS and MS/MS analysis of phospholipid molecular species was performed on a triple quadrupole mass spectrometer.
Results: :
Analysis of rat retina fatty acids at 9 weeks of diabetes demonstrated an 85% decrease of DHA in diabetic rats relative to nondiabetic rats. Furthermore, a 50% decrease in several DHA-containing molecular species of phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine was observed. Dietary supplementation with DHA completely prevented diabetes-induced total retina DHA decrease, and DHA-containing phospholipid species were restored to nearly nondiabetic levels.
Conclusions: :
Loss of retinal DHA from abundant membrane phospholipid species may contribute to the pathology of diabetic retinopathy. Dietary DHA supplementation blocks the overall loss of DHA in diabetic retinas and minimizes the loss of DHA from phospholipid species.
Keywords: lipids • diabetic retinopathy • diabetes