Pré-condicionamento nutricional com misturas de óleos ômega-3, 6 e 9 na isquemia e reperfusão cerebral em ratos

Abstract

Omega-3 (ω-3) and omega-9 (ω-9) unsaturated fatty acids are anti-inflammatory and antioxidant, while omega-6 (ω-6) fatty acids are pro-inflammatory. This study investigated the preconditioning effects of fatty acids mixes with low ratio ω-6/ω-3 and high ratio ω-9/ω-6, in a brain ischemia-reperfusion experimental model. Forty-two Wistar rats were aleatory assigned to two groups: Control (n=24) and Test (n=18). Control group was divided into 4 groups, each with 6 animals: Water-Simulated (Water-Sim), Water - Ischemia-Reperfusion (Water-IR), Isolipid-Simulated (Isolipid-Sim) and Isolipid - Ischemia-Reperfusion (Isolipid-IR). The animals received water or a isolipid mix with ω-6/ω-3 ratio of 8:1 and ω-9/ω-6 ratio of 0,4:1 by gavage, for 7 days, according to their groups. Test group was divided into 3 groups of 6 animals: Mix1-IR, Mix2-IR, and Mix3-IR. All animals from Test group received oil mixes with ω-6/ω-3 ratio of 1,4:1 and ω-9/ω-6 ratio of 3,4:1 , differing only on the ω-3 source: Mix1, with ω-3 linolenic acid; Mix2, with ω-3 linolenic, eicosapentaenoic and docosahexaenoic acids, and Mix 3, with ω-3 linolenic and docosahexaenoic acids, by gavage, for 7 days. At the 7th day, animals from Water-IR, Isolipid-IR, Mix1-IR, Mix2-IR, and Mix3-IR groups were subjected to 1-hour brain ischemia by occlusion of both common carotid arteries, followed by a 3-hour reperfusion. Animals from Water-Sim and Isolipid-Sim groups were submitted to a simulated operation. At the end of the experiment, all animals were decapitated and their brains were sliced and sent to histological analysis of the CA3 hippocampal region. Neuronal death was quantified by the red neurons (RN) count. It was found that the number of RN in Water-IR group (36.83 ± 9.79) was higher (P = 0.0046) than the number observed in Water-Sim group (17.67 ± 8.48), and similarly, the number of RN in Isolipid-IR group (29.83 ± 12.19) was higher (P = 0.0459) than the number observed in Isolipid-Sim group (14.17 ± 11.62). There was no difference between the amount of RN from Water-Sim (17.67 ± 8.48) and Isolipid-Sim (14.17 ± 11.62) groups, nor between Water-IR (36.83 ± 9.79) and Isolipid-IR (29.83 ± 12.19) groups. The number of RN in Mix1-IR group (12.33 ± 6.31) was lower than the number seen in Water-IR (36.83 ± 9.79; P < 0.01) and Isolipid-IR (29.83 ± 12.19; P < 0.05) groups. The amounts of RN in Mix2-IR (10.67 ± 2.81) and Mix3-IR (7.33 ± 6.47) groups were also lower than the amounts observed in IR-Water (36.83 ± 9.79; P < 0.001) and IR-Isolipid (29.83 ± 12.19; P < 0.01) groups. There were no differences between the Mix1-IR (12.33 ± 6.31), Mix2-IR (10.67 ± 2.81) and Mix3-IR (7.33 ± 6.47) groups. In conclusion, regardless of the source of ω-3, preconditioning with fatty acids mixes with low ratio ω-6/ω-3 and high ratio ω-9/ω-6, protects the neurons against brain ischemia-reperfusion injuries in this experimental model.