Neuroprotective Effects of Hydrogen Sulfide Against Early Brain Injury and Secondary Cognitive Deficits Following Subarachnoid Hemorrhage

Although the neuroprotective effects of hydrogen sulfide (H₂S) have been demonstrated in several studies, whether H₂S protects against early brain injury (EBI) and secondary cognitive dysfunction in subarachnoid hemorrhage (SAH) model remains unknown. This study was undertaken to evaluate the influence of H₂S on both acute brain injury and neurobehavioral changes as well as the underlying mechanisms after SAH. The H₂S donor, NaHS, was administered via an intraperitoneal injection at a dose of 5.6 mg/kg at 2 h, 6 h, 24 h, and 46 h after SAH in rat model. The results showed that NaHS treatment significantly improved brain edema and neurobehavioral function, and attenuated neuronal cell death in the prefrontal cortex, associated with a decrease in Bax/Bcl‐2 ratio and suppression of caspase‐3 activation at 48 h after SAH. NaHS also promoted phospho‐Akt and phospho‐ERK levels. Furthermore, NaHS treatment significantly enhanced the levels of brain‐derived neurotrophic factor (BDNF) and phospho‐CREB. Importantly, NaHS administration improved learning and memory performance in the Morris water maze test at 7 days post‐SAH in rats. These results demonstrated that NaHS, as an exogenous H₂S donor, could significantly alleviate the development of EBI and cognitive dysfunction induced by SAH via Akt/ERK‐related antiapoptosis pathway, and upregulating BDNF‐CREB expression.