O papel do óleo de peixe na via L-arginina-óxido nítrico e no estresse oxidativo em eritrócitos: um estudo dose-resposta

Abstract

The n-3 polyunsaturated fatty acids derived from fish oil are associated with cardiovascular benefits and it has been suggested that the activation of nitric oxide synthase (NOS) would be a potential mechanism responsible for its effects. Beside endothelial cells, red blood cells (RBC) possess endothelial NOS (eNOS) and inducible NOS (iNOS), and thus are capable of synthesizing their own nitric oxide (NO). The present study tested the capacity of different amounts of fish oil to activate L-arginine-NO pathway and therefore alter cyclic guanosine monophosphate (cGMP) levels in RBC from mice fed on a high fat diet. Additionally, the oxidative status in RBC was performed to investigate NO bioavailability. L-arginine transport, assessed by incubation with L-[3H]-arginine, was activated by higher doses of fish oil, compared to control diet and to lowest doses of fish oil. RBC NOS activity, measured by the conversion of L-[3H]-arginine into L-[3H]-citrulline, and eNOS expression were also enhanced by diets rich in fish oil. Despite the L-arginine-NO activation, no effect on intra RBC cGMP basal levels was seen among the groups. Oxidative damage of RBC rises linearly with increasing amounts of fish oil in the diet without affecting the activity of antioxidant enzymes. Besides endothelium, red blood cells also contribute regulating the NO bioactivity. Therefore, the activation of L-arginine-NO pathway in RBC by fish oil would be beneficial in cardiovascular health. Future studies testing other oxidant markers during dietary fish oil supplementation will be necessary to verify that its consumption does not result in detrimental secondary effects and to ensure NO bioavailability.