As a subtype of
stroke,
subarachnoid hemorrhage (SAH) has a notoriously high rate of disability and mortality owing to the lack of effective intervention. Early
brain injury (EBI) is the main factor responsible for the dismal prognosis of SAH patients. The current study intends to explore the molecular mechanism underlying the effect of MH on EBI after SAH from a novel perspective of pyroptosis, a highly specific inflammatory programmed cell death, in the SAH rat model. Sprague-Dawley (SD) rats were divided into different groups in accordance with various treatments. In the treatment group, the rats underwent mild
hypothermia for 4 h after modeling; in the inhibitor group, Compound C (an inhibitor of AMPK) was administered
intravenous injections (i.v.) 30 min before modeling. Neurological score, neuronal
death, brain water content, inflammatory reaction, and expression levels of pyroptosis-related
proteins were evaluated in the rats. Our results indicate that the MH
therapy significantly increased the neurological score and assuaged
brain edema, neuronal injury, and inflammatory reaction induced by SAH. Meanwhile, MH
therapy upregulated the level of AMPK phosphorylation whereas downregulated the
protein expressions of NLRP3, ASC, cleaved caspase-1, GSDMD, IL-1β, and
IL-18. The reversed effect of MH
therapy by Compound C concretely indicated that MH
therapy inhibited pyroptosis through an AMPK-dependent pathway. Our study also found that MH
therapy potently curbed the increasing trend of brain temperature (BT), rectal temperature (RT), and ICP after SAH. Taken together, our data indicate that the
neuroprotective effects of MH
therapy were manifested by inhibiting pyroptosis via the AMPK/NLRP3
inflammasome pathway, which may serve as a promising
therapy for the intervention of SAH.