Natural mineral-rich water ingestion by ovariectomized fructose-fed Sprague-Dawley rats: effects on sirtuin 1 and glucocorticoid signaling pathways

Abstract

Objective: Prevention or induction of metabolic disorders and obesity depend on estrogen signaling and/or exogenous factors, such as mineral content in diet. The protective effects of a Portuguese natural mineral-rich water against the induction of metabolic syndrome in fructose-fed male Sprague-Dawley rats have been reported. The present study was designed to assess the impact of this mineral-rich water on fructose-fed estrogen-deficient female Sprague-Dawley rats. Methods: Ovariectomized rats had access to tap (TWO) or mineral-rich (MWO) waters, with and without 10% fructose (10-wk treatment). A sham-operated (tap water supplied) group was included and each of the five groups included six rats. Plasma biochemical and metabolic parameters were evaluated by routine clinical measurements. Western blotting was used to assess hepatic protein expression of sirtuins (Sirt) 1 and 3, phosphorylated AMPactivated protein kinase-a (p-AMPKa), peroxisome proliferator-activated receptor gamma coactivator-1-a (PGC1a), glucocorticoid receptor, and 11beta-hydroxysteroid dehydrogenase type 1 (11bHSD1). Results: Ovariectomy increased plasma total cholesterol (46%/P<0.05), but had no significant effects on hepatic protein expression. Fructose intake by ovariectomized rats increased PGC1a and 11bHSD1 (fructose in tap water [TWFO] vs TWO: 65%/P<0.05 and 38%/P ¼ 0.05, respectively) as well as glucocorticoid receptor (TWFO and fructose in natural mineral-rich water [MWFO] vs TWO and MWO: 107%/P¼0.05 and 182%/P<0.05, respectively). Mineral-rich water ingestion exerted an increasing shape on Sirt1 (MWO vs TWO: 76%/P<0.05; MWFO vs TWFO: 76%/P¼0.06), PGC1a (MWO vs TWO: 77%/P<0.01), p-AMPKa (MWO vs TWO: 152%/P¼0.01; MWFO vs TWFO: 107%/P¼0.01), and 11bHSD1 (MWO vs TWO: 91%/P¼0.05; MWFO vs TWFO: 47%/P¼0.05). Conclusions: Mineral-rich water ingestion may have a prime role on the activation of Sirt1 signaling and the modulation of glucocorticoid signaling in the postmenopause.