Sex differences in respiration and redox homeostasis of heart mitochondria in rats on high-fructose diet

Sex hormones play a leading role in the sexual dimorphism of mitochondrial dysfunction and oxidative stress that are associated with Metabolic Syndrome (MetS) and considered as possible causes of cardiovascular disease. The aim of the work was to determine mitochondrial respiration and redox homeostasis in the heart mitochondria of high-fructose diet-fed (НFD) rats depending on sex. MetS was induced in Wistar rats by 8 weeks intake of fructose (200 g/l) with drinking water. The experiment was performed on 30 rats divided into five groups: control males, control females, HFD-fed males, HFD- fed females with intact ovaries, ovariectomized HFD-fed females. Heart mitochondria were isolated and indicators of redox homeostasis as well as mitochondrial oxygen consumption rate were determined. Heart mitochondria of intact female rats were characterized by a lower intensity of lipid peroxidation, a higher activity of antioxidant defense system and state 3 respiration in comparison with control males. HFD was shown to induce more expressed oxidative stress due to significant inhibition of enzymatic and non-enzymatic components of antioxidant defese and more pronounced dysregulation of mitochondrial respiration in the heart mitochondria of ovariectomized females as compared to males. This data may partially explain the greater cardiovascular risk in women with low estrogen sufficiency and justify the necessity of new sex-specific prevention and treatment of cardiovascular risk approaches. Keywords: antioxidant defense system, heart mitochondria, mitochondrial respiration, oxidative stress, rats, sex differences