Efeito do ômega-3 sobre padrões eletrocorticográficos de ratos Wistar adultos expostos à radiação ionizante

Abstract

Cancer treatments, such as radiotherapy, have a profound impact on the body's physiology, causing direct and indirect effects on living structures, which can affect the metabolism of proteins, lipids and carbohydrates. Lipids are the main forms of energy reserve in most organisms and they perform a variety of cellular functions. Among these, the polyunsaturated fatty acids of the omega-3 series stand out for having beneficial effects on human health. In view of this, this work sought to verify the effect over the brain activity of supplementation with omega-3 in Wistar rats that were exposed to ionizing radiation at a dose of 18 Gy on head and neck regions, the same dose used in radiotherapy treatments. 16 Rattus norvegicus were used, divided into 2 experimental groups, a group of animals supplemented with fish oil (GT) (1ml / OW / day / 100g LW) (n = 8), which is rich in omega-3, and another group who received a solution of 0.9% NaCl (GNT) (1ml / OW / day / 100g LW) (n = 8), both group were evaluated 24 hours before irradiation, in 24 hours and 1 week after irradiation. At the 17th postnatal week, the animals were submitted to a surgical procedure to implant electrodes. On the 15th postoperative day, the animals were irradiated. The ECoG recording of the animals was performed during space exploration of 24 hours pre-exposure, 24 hours post-exposure and 1 week post-exposure during 30 minutes. The ECoG signals were amplified, recorded and segmented. In the analysis of the time series of the ECoG signal, the power spectrum (PS) and the detrended fluctuation analysis (DFA) were used. These mathematical methods were sensitive in detecting changes in ECoG, due to the effect of omega-3 and radiation. In animals treated with omega-3, the PS technique showed that there was a significant decrease (p = 0.0184) in the beta rhythm power. While the DFA technique was applied to the different frequency ranges (theta, delta, alpha and beta) it revealed a statistically significant difference only for the theta wave (p = 0.0003). In the evaluation of the radiation effect through the PS, it was observed an increase in the power of the theta rhythm of the ECoG (p = 0.0453), only when they were evaluated one week after the irradiation (Late effect). Regarding the effect of radiation in animals treated with omega-3, it was observed that there was an increase in the power of the theta rhythm of the ECoG (p = 0.0220), only when they were evaluated one week after irradiation. The DFA technique applied to the different frequency bands also showed a statistically significant difference for the theta wave (p = 0.0053) in the group with omega-3 and non-irradiated in relation to the group with omega-3 and irradiated, groups evaluated one week after exposure to ionizing radiation. Difference also was found in the evaluation carried out between the group without omega-3 and with omega-3, after 24 hours (0.0055) and 1 week (p = 0.0252) of the irradiation. As for the beta rhythm, in the evaluation performed 1 week after irradiation, the DFA of the different frequency bands showed an alteration (p = 0.0067) between the group without and with omega-3.