Anti-oxidative effects of 17 β-estradiol and genistein in human skin fibroblasts and keratinocytes

Background: Estrogens and phytoestrogens can hinder the aging process through mechanisms related to estrogen receptors (ERs), guanine nucleotide-binding protein-coupled receptor (GPER30), mitochondria function and nitric oxide (NO) release. Up to date, however, the above issues are a matter of debate. Objective: To examine the effects elicited by 17 β-estradiol and genistein against peroxidation in human keratinocytes/fibroblasts and evaluate the role played by ERs, GPER30, mitochondria and NO. Methods: Human fibroblasts/keratinocytes, either subjected to peroxidation or not, were exposed to 17 β-estradiol/genistein in the absence or presence of the NO synthase (NOS) inhibitor, the ERs and GPER30 blockers, fulvestrant and G15, the phosphatidyl-inositol-3-kinase (PI3K-Akt), the p38 mitogen-activated protein (MAP) kinase and the extracellular signal–regulated kinases (ERK) 1/2 inhibitors. Specific kits were used for cell viability, NO, ROS and glutathione (GSH) detection and mitochondrial membrane potential measurement. Western Blot analysis was performed for kinases expression/activation detection. Results: In physiological and peroxidative conditions, 17 β-estradiol/genistein respectively increased and reduced NO release by fibroblasts/keratinocytes. Moreover, both agents prevented the ROS release and the fall of cell viability and mitochondrial membrane potential, while increasing GSH levels and the proliferation rate. Fulvestrant and G15 counteracted all above responses. Also, the NOS, and the kinases blockers reduced the protection exerted by 17 β-estradiol/genistein on cell viability/mitochondria function. The involvement of PI3K-Akt and p38-MAPK was confirmed by Western blot. Conclusion: 17 β-estradiol/genistein protected fibroblasts/keratinocytes against peroxidation by modulating oxidant/antioxidant system and mitochondria membrane potential, through mechanisms related to ERs and GPER30 and kinases activation.