Antioxidant activity of vitamin E on the oxidation of serum lipids and liver Wistar rats supplemented with polyunsaturated fatty acids omega-3 / Ação antioxidante da vitamina E sobre a oxidação lipidica serica e hepatica de ratos wistar suplementados com acidos graxos poliinsaturados omega-3

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

The objective of this research was to study a possible protective effect of vitamin E against lipid oxidation in the blood and liver of Wistar rats fed on a AIN93-G diet supplemented by gavagem with polyunsaturated omega-3 fatty acids. For the first biological assay, 60 albino recent1y weaned male Wistar rats were used, distributed at random into 6 experimental groups. The experimental groups under study were divided according to the amount and brand of supplement, with and without vitamin E: GROUP 1 - Control - supplementation with 2 g/day soybean oil; GROUP 2 - supplementation with 2 g/day brand A omega-3 fatty acids with vitamin E (120 mg/day); GROUP 3 - supplementation with 2 g/day brand B omega-3 fatty acids without vitamin E; GROUP 4 -supplementation with 1 g/day brand A omega-3 fatty acids with vitamin E (60 mg/day); GROUP 5 - supplementation with 1 g/day brand B omega-3 fatty acids without vitamin E; GROUP 6 ? supplementation with 2 g/day brand B omega-3 fatty acids without vitamin E for a period of 30 days and subsequent1y for 15 days with vitamin E (brand C - 400 mg DL-?-tocopherol). In this group no animals were sacrificed at Time 1. In the second biological assay, 80 albino recently weaned male Wistar rats were used. Analyses were carried out at 3 points in time: TO - reference value after 3 days of adaptation on the basal diet (12 animals sacrificed, n=12); T1 after 30 days of supplementation (4 animals sacrificed per group, n=8) and T2 after 45 days of supplementation (4 animals sacrificed per group, n=4). The 80 animals were first weighed and submitted to an eight day period of acclimatization to the environment in individual growth cages, fed on a non-purified closed formula Nuvital® diet in order to gain weight. They were then distributed at random into four experimental groups, 16 animals per group, and fed for a further 4 days of adaptation on the basal diet before carrying out a weight alignment, when 4 animals per group were removed and sacrificed for a lipid analysis of their blood and liver. This analysis was considered as the "reference value" and denominated "Time O". Sixty-four animals thus remained (16 animals per group) of which, after 30 days of the experiment, 8 animals per group were removed for blood and liver analyses, denominated "Time 1", and after a further 15 days, another analysis, denominated "Time 2" was carried out on the remaining animals to evaluate the serum and hepatic lipid profiles, total lipids, omega-3 polyunsaturated fatty acids and the vitamin E content, as well as the anti-oxidant activity of the vitamin E. The animals were supplemented by gavagem for 45 consecutive days, via oral. The experimental groups under study were divided according to the amount and brand of supplement, with and without vitamin E: GROUP 1 - Control - supplementation with 2 g/day soybean oil; GROUP 2 - supplementation with 2 g/day brand A omega-3 fatty acids with vitamin E (120 mg/day); GROUP 3 -supplementation with 2 g/day brand B omega-3 fatty acids without vitamin E; GROUP 4 - supplementation with 2 g/day brand B omega-3 fatty acids without vitamin E; GROUP 5 - supplementation with 2 g/day brand B omega-3 fatty acids without vitamin E for a period of 30 days and subsequent1y for 15 days with vitamin E (brand C - 400 mg DL-?-tocopherol). In this group no animals were sacrificed at Time 1. With respect to the anti-oxidant effect of vitamin E on the peroxide index (PI) values and on the thiobarbituric acid reactive substances (TBARS), it was observed that in the experimental groups receiving ?-3 PUFA without vitamin E, the values for PI and for TBARS were much higher than for the experimental groups supplemented with ? -3 PUFA with vitamin E. Thus it was shown that vitamin E had a protective effect against lipid oxidation at the cellular level in Wistar rates supplemented with products based on ?-3 PUFA. No significant difference (p>0,05) was observed between the means for diet consumption (g) and weight gain (g), showing that supplementation with ?-3 PUFA, with and without vitamin E, did not interfere with these variables, and that the time of supplementation with ?-3 PUFA was not capable of improving the serum lipid profile of the rats, just a reduction in the levels of serum LDL-cholesterol being observed. Supplementation with ?-3 PUF A did not reduce the levels of total cholesterol or triglycerides in the rat livers. With respect to the variation of the levels of saturated, mono-unsaturated and poly-unsaturated fatty acids in the blood and liver, it was observed that during the 45 days of supplementation with ?-3 PUF A, there was an increase in the levels of the saturated fatty acids palmitic and stearic acids, oleic acid, ?-linolenic acid and DHA. The addition of vitamin E did not interfere with the values found. Considering the results obtained it can be recommended that, if using supplementation with ?-3 PUFA in a concentrated form in soft gels, it should be associated with vitamin E to avoid risks of oxidation at the cellular level, thus causing damage to the health

ASSUNTO(S)

rato vitamin e acidos graxos omega-3 omega-3 fatty acids antioxidantes antioxidants mouse vitamina e

ACESSO AO ARTIGO

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