Purpose: Diet-induced deficiencies in Omega-3 (omega-3) fatty acids are well known to alter photoreceptor function. In this study, the broader functional changes in a diversity of retinal neurons were considered.
Methods: Sprague-Dawley dams were fed either omega-3-sufficient (omega-3(+), n = 21) or -deficient (omega-3(-), n = 19) diets 5 weeks before conception, with the pups continued on the mothers' diet. After 20 weeks of age, electroretinograms (ERGs) were recorded by using protocols that isolate separate cellular generators, including; photoreceptors (PIII), ON-bipolar cells (PII), and ganglion/amacrine cells (STR). At the brightest energies, rod and cone responses were isolated with a paired-flash paradigm. Retinal tissue (omega-3(+), n = 5; omega-3(-), n = 5) was harvested at 23 weeks of age for fatty acid assays with thin layer and gas liquid chromatography.
Results: Omega-3 deficiency caused a 48.6% decrease in total retinal docosahexaenoic acid (DHA). This change induced significant amplitude decreases only in the rod PII (-8.2%) and positive (p)STR components (-27.4%), with widespread delays in all signals (PIII 5.7%, PII 13.6%, pSTR 7.6%, and negative [n]STR 8.3%). Omega-3 deficiency exerted its greatest effects on signals originating in the inner retina (pSTR).
Conclusions: Increasing dietary omega-3 has beneficial effects across the retina, with the greatest improvement occurring in ganglion cell function.