Evidence on n-3 Fatty Acids and Oleic Acid Role in Retinal Inflammation and Microvascular Integrity: Insight from a Hyperlipidemic Rat Model

Loss of retinal function due to manifestation of chronic inflammation and oxidative stress in hyperglycemia is well addressed. However, the effect of hyperlipidemia on retinal inflammation and microvascular integrity, and the modulatory effects of oxidation-stable oleic acid and long-chain n-3 fatty acids have never been addressed. The objective of this investigation was to assess the retinoprotective effect of oxidation stable oleic acid and oxidation-susceptible EPA + DHA on retinal inflammation and microvascular integrity, under hyperlipidemic conditions. Male Wistar rats were fed with control (7.0% lard), high-fat (35.0% lard), high-fat with fish oil (17.5% fish oil + 17.5% lard), high-fat with olive oil (17.5% olive oil + 17.5% lard), and high-fat with fish oil and olive oil (11.66% fish oil + 11.66% of olive oil + 11.66% of lard) diet for 90 days. Systemic and retinal inflammation, as measured by eicosanoids and cytokines, retinal expression of NF-kB, capillary degeneration, and pericyte loss, were assessed. Hyperlipidemia significantly (p < 0.05) increased the markers of inflammation (PGE₂, LTB₄, LTC₄, IL-1β, MCP-1, and TNF-α) in serum and retina. Besides, the retinal NF-kB-p65 expression, capillary degeneration, and pericyte loss were significantly (p < 0.05) increased under hyperlipidemic conditions. Dietary incorporation of oleic acid and EPA + DHA significantly (p < 0.05) suppressed hyperlipidemia-induced effects in the retina. In conclusion, hyperlipidemia causes retinal aberrations by compromising the balance in the inflammatory response and microvascular integrity. Dietary incorporation of oleic acid and long-chain n-3 fatty acids prevents hyperlipidemia-induced aberrations in the retina.