Hydrogen-Rich Saline Attenuated Subarachnoid Hemorrhage-Induced Early Brain Injury in Rats by Suppressing Inflammatory Response: Possible Involvement of NF-κB Pathway and NLRP3 Inflammasome

Early brain injury (EBI), highlighted with inflammation and apoptosis, occurring within 72 h after subarachnoid hemorrhage (SAH), is associated with the prognosis of SAH. Recent studies have revealed that hydrogen-rich saline (HS) exerted multiple neuroprotective properties in many neurological diseases including SAH, involved to anti-oxidative and anti-apoptotic effect. We have previously reported that HS could attenuate neuronal apoptosis as well as vasospasm. However, the underlying mechanism of HS on inflammation in SAH-induced EBI remains unclear. In this study, we explored the influence of HS on nuclear factor-kappa B (NF-kappa B) pathway and nucleotide binding and oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome at early stage after SAH, by injecting HS intraperitoneally to SAH rats. One hundred and twenty-nine SD rats were randomly divided into four groups: sham group, SAH group, SAH+vehicle group, and SAH+HS group. SAH model was conducted using endovascular perforation method; all rats were sacrificed at 24 h after SAH. Protein level of pI kappa B alpha, cytosolic and nuclear p65, NLRP3, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), caspase-1, interleukin-1 beta (IL-1 beta), and cleaved caspase-3 were measured by western blot. mRNA level of IL-1 beta, interleukin-6 (IL-6), tumor necrosis factor-c (TNF-alpha) were evaluated by RT-PCR. Cellular injury and death was detected by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and Nissl staining, respectively. Our results showed that pI kappa B alpha, nuclear p65, NLRP3, ASC, caspase-1, IL-1 beta, cleaved caspase-3 proteins, as well as the mRNA of IL-1 beta, IL-6, and TNF-E increased at 24 h after SAH, while cytosolic p65 decreased. TUNEL and Nissl staining presented severe cellular injury at 24 h post-SAH. However, after HS administration, the changes mentioned above were reversed. In conclusion, HS may inhibit inflammation in EBI and improve neurobehavioral outcome after SAH, partially via inactivation of NF-kappa B pathway and NLRP3 inflammasome.