17β-Estradiol enhances sulforaphane cardioprotection against oxidative stress

Introduction Many aspects of cardiovascular diseases are similar in man and women, but some differences on risk profile, age of onset and response to medical treatments are emerging. The incidence of ischemic heart disease is significantly lower in women than in men until menopause. This observation suggests that female sex hormones, such as estrogen, may have a cardioprotective role. Our hypothesis is that sex hormones could modulate the protective effects of some nutraceutical compounds, such as the isothiocyanate sulforaphane, present in Brassica vegetables. This study was designed to explore the protective role of low concentrations of sulforaphane in the presence/absence of 17β-estradiol against oxidative stress in cardiomyocytes. Methods Primary cultures of cardiomyocytes were obtaind from 1-2 days old Sprague-Dawley rats. Cell viability was evaluated by MTT and LDH assays, ROS production by 2,7-dichlorodihydrofluorescein diacetate assay and immunofluorescence staining with anti-8-hydroxyguanosine, GSH levels by the monochlorobimane assay, antioxidant enzyme expression by RT-PCR. Transmission electron Microscopy analysis was performed to investigate the ultrastructure of cells. Results Cardiomyocytes were treated with sulforaphane and/or 17β-estradiol. Sulforaphane and 17β-estradiol co-treatment led to a higher level of protection against H2O2 induced oxidative stress than sulforaphane or 17β-estradiol alone. The co-treatment significantly reduced intracellular ROS levels in respect to 17β-estradiol or sulforaphane and increased the expression of different antioxidant enzymes in respect to sulforaphane or 17β-estradiol alone. As expected. The co-treatment increased GSH intracellular levels. Cells under oxidative stress showed a damaged cytoplasmic morphology, with several vacuoles, dilated rough endoplasmic reticulum and mitochondrial cristae. Co-treatment protected cells from oxidative stress damage, showing well preserved cytoplasmic organelles and nuclear morphology. Conclusions Our results demonstrated, for the first time, that estrogens could modify sulforaphane protective effects, suggesting that nutraceutical efficacy might be different in male and female gender.