Sandra Sobočanec1, Ana Šarić2, Željka Mačak Šafranko1, Marijana Popović Hadžija1, Marija Abramić3, Tihomir Balog1. 1. Division of Molecular Medicine, Ruđer Bošković Institute, Zagreb, Croatia. 2. Division of Molecular Medicine, Ruđer Bošković Institute, Zagreb, Croatia. Electronic address: ana.saric@irb.hr. 3. Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Zagreb, Croatia.
Abstract
AIMS: We aimed to explore the impact of surgical 17β-estradiol (E2) deprivation/administration on the expression of antioxidant enzymes with an emphasis on the alteration of the NF-E2-related factor 2/Kelch-like ECH-associated protein 1 (Nrf2/Keap1) pathway under physiological conditions in the livers of CBA/H mice of both sexes. MAIN METHODS: Hepatic oxidative stress markers were determined by measuring lipid peroxidation and DNA damage using the comet assay. The expression and activities of two isoforms of superoxide dismutase (Sod-1, Sod-2) and catalase (Cat) were studied using real-time PCR, Western blot and spectrophotometrical analyses. The effect of E2 on Nrf2/Keap1 protein levels and localization was assessed using cytosolic and nuclear fractions. KEY FINDINGS: We demonstrate the E2-mediated repression of the antioxidant enzymes Sod-1, Sod-2 and Cat in the livers of ovariectomized mice treated with E2 and its association with a decreased level of Nrf2/Keap1 proteins in the nucleus. We observed beneficial effects of long-term E2 administration on lipid peroxidation but not on DNA damage in the livers of ovariectomized mice. SIGNIFICANCE: The results of this study may additionally confirm the protective ability of E2 in prolonging the onset of age-related disease in females that ultimately contributes to their longer lifespan.
AIMS: We aimed to explore the impact of surgical 17β-estradiol (E2) deprivation/administration on the expression of antioxidant enzymes with an emphasis on the alteration of the NF-E2-related factor 2/Kelch-like ECH-associated protein 1 (Nrf2/Keap1) pathway under physiological conditions in the livers of CBA/H mice of both sexes. MAIN METHODS: Hepatic oxidative stress markers were determined by measuring lipid peroxidation and DNA damage using the comet assay. The expression and activities of two isoforms of superoxide dismutase (Sod-1, Sod-2) and catalase (Cat) were studied using real-time PCR, Western blot and spectrophotometrical analyses. The effect of E2 on Nrf2/Keap1 protein levels and localization was assessed using cytosolic and nuclear fractions. KEY FINDINGS: We demonstrate the E2-mediated repression of the antioxidant enzymes Sod-1, Sod-2 and Cat in the livers of ovariectomized mice treated with E2 and its association with a decreased level of Nrf2/Keap1 proteins in the nucleus. We observed beneficial effects of long-term E2 administration on lipid peroxidation but not on DNA damage in the livers of ovariectomized mice. SIGNIFICANCE: The results of this study may additionally confirm the protective ability of E2 in prolonging the onset of age-related disease in females that ultimately contributes to their longer lifespan.