Effects of lipoic acid and n-3 long-chain polyunsaturated fatty acid on the liver ovariectomized rat model of menopause

Bilateral ovariectomy is an experimental model used to analyse the effects of menopause and develop strategies to mitigate the deleterious effects of this condition. Supplementation of the diet with antioxidants has been used to reduce potential oxidative stress caused by menopause. The purpose of the study was to analyse the effects of α-lipoic acid (LA), docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), dietary supplementation on oxidative stress in the livers of ovariectomized rats. In this study, we evaluated the effect of dietary supplementation with LA, DHA and EPA for a period of 16 weeks on oestrogen levels and oxidative stress biomarkers in the livers of ovariectomized 25 three-month-old rats. Serum oestrogen levels were lower after ovariectomy but were not altered by dietary treatments. LA was capable of acting in the liver, recovering the activity of the antioxidant enzymes superoxide dismutase and glutathione peroxidase, and reducing protein oxidative damage. Moreover, LA supplementation reduced nitrite and nitrate levels. DHA and EPA recovered the antioxidant activity of cytosolic and mitochondrial superoxide dismutase, decreasing protein oxidation. Protection against lipid oxidation differed between treatments. The DHA-treated group showed increased levels of the lipid peroxidation biomarker malondialdehyde compared to the ovariectomized group. However, malondialdehyde levels were not altered by EPA treatment. The results suggest that the antioxidant response varies among evaluated supplementations and all supplements were able to alter enzymatic and non-enzymatic antioxidants in the livers of ovariectomized rats. DHA presented the most evident antioxidant effect, decreasing protein and lipid damage.