Empagliflozin Protects Against Oxidative Stress in the Diabetic Brain by Inducing H₂S Formation

Background: Hydrogen sulfide (H₂S) is an endogenously produced gaseous neurotransmitter. H₂S donors exhibited neuroprotection in oxidative-stress-related disorders in preclinical studies, but odor and short half-lives have limited their clinical use. However, endogenous H₂S stimulators with antioxidant properties have advantages over H₂S donors regarding safety and patient compliance. Empagliflozin (EMPA), a sodium-glucose cotransporter-2 (SGLT2) inhibitor widely used in the treatment of diabetes mellitus (DM), exerted similar neuroprotective and antioxidant effects as H₂S and shares common mechanisms. This study aimed to investigate the role of H₂S in the antioxidant effects of EMPA in the brain. Methods: The effects of EMPA on H₂S production and reactive oxygen species (ROS) formation were assessed ex vivo in mouse brain under normal conditions and pyrogallol-induced oxidative stress. Moreover, rats were divided into the following four groups: nondiabetic, EMPA-treated nondiabetic, streptozotocin (STZ)-induced diabetic, and EMPA-treated, STZ-induced diabetic. Endogenous H₂S and ROS levels in the brain were measured using methylene blue and chemiluminescence assays, respectively. Results: Ex vivo EMPA treatment significantly increased endogenous H₂S formation in both healthy and pyrogallol-induced oxidative stress, as well as reduced ROS formation in mouse brain; these effects were significantly reversed by the H₂S synthesis inhibitor aminooxyacetic acid (AOAA). Oral EMPA administration significantly elevated brain H₂S levels in both nondiabetic and diabetic rats and reduced ROS formation. These effects were inhibited by AOAA. Conclusions: Our study revealed a novel mechanism by which EMPA can reduce oxidative stress in neurodegenerative disorders by triggering H₂S synthesis in the brain.