Objective: Hydrogen sulfide (H2S), generated in the myocardium predominantly via cystathionine-γ-lyase (CSE), is cardioprotective. The objectives of the present study were to investigate the effects of estrogens on CSE expression and H2S generation in the myocardium and to examine whether serum 17β-estradiol (E2) level is associated with CSE activity and H2S generation and whether H2S or E2 level is associated with proinflammatory cytokines and oxidative stress status.
Methods: Ovariectomized Sprague-Dawley rats received subcutaneous E2 (30 μg/kg/d) or vehicle for 12 weeks. At the end of the 12-week treatment, CSE expression, H2S generation, reduced glutathione/oxidized glutathione (GSH/GSSG) ratio, total antioxidant capacity (T-AOC), superoxide dismutase (SOD) activity, catalase (CAT) activity, interleukin (IL)-6 concentration, and tumor necrosis factor-α (TNF-α) concentration in the left ventricle were determined.
Results: E2 increased CSE expression and H2S generation in the myocardium of ovariectomized rats. H2S production rate and serum E2 were positively correlated. E2 increased GSH/GSSG ratio, T-AOC, CAT, and SOD activity but decreased IL-6 and TNF-α levels. Serum E2 level was positively correlated with GSH/GSSG ratio, T-AOC, CAT, and SOD activity, and inversely correlated with IL-6 and TNF-α levels. H2S generation rate was positively correlated with T-AOC and GSH/GSSG ratio, and inversely correlated with IL-6 and TNF-α levels.
Conclusions: E2 increases CSE expression and endogenous H2S generation in the myocardium. The effects of E2 are associated with decreased oxidative stress and inflammatory status. Our data suggest that estrogens might exert cardioprotective effects through up-regulation of CSE expression and H2S generation.