Neuronal pyroptosis mediated by STAT3 in early brain injury after subarachnoid hemorrhage

Neuroinflammation induced by early brain injury (EBI) seriously affects the prognosis of patients after subarachnoid hemorrhage (SAH). Pyroptosis can aggravate inflammatory injury by promoting the secretion of inflammatory cytokines. Meanwhile, STAT3 plays a critical role in the inflammatory response of EBI after SAH. However, whether it plays a pyroptotic role in SAH is mainly unknown. This study aimed to explore the mechanism of STAT3 in pyroptosis in EBI after SAH. C57BL/6J mice were used to establish the SAH model. Brain tissues were collected at different time points for q-RT-PCR and western blot to detect the expression level of STAT3. After intracerebroventricular injection of STAT3 inhibitor S3I-201, they were divided into sham, SAH, SAH + Vehicle, and SAH + S3I-201. Then, the SAH grade, cerebral edema content, blood–brain barrier (BBB) damage, and neurological scores of mice in each group were detected. qRT-PCR and western blot were used to detect related genes and proteins, and enzyme-linked immunosorbent assay (ELISA) was used to detect the expression levels of IL-18 and IL-1β. Immunofluorescence staining was used to observe the expression level of proteins. At the same time, S3I-201 was added to the primary neuron cells of the culture medium containing OxyHb to simulate the in vitro experiment, and the relevant indicators consistent with the in vivo experiment were detected. The expression of STAT3 was upregulated after SAH. Inhibition of STAT3 with S3I-201 attenuated neurological deficits, cerebral edema, and BBB damage after SAH. In addition, S3I-201 can also reduce the expression of pyroptosis-related inflammasomes such as GSDMD, NLRP3, Caspase 1, and AIM2 after SAH and the neurological damage caused by IL-18 and IL-1β. Further studies have shown that STAT3 regulates pyroptosis by promoting the nuclear translocation of NF-κB p65. Our finding demonstrated that STAT3 regulates neuronal pyroptosis in EBI after SAH. Inhibition of STAT3 may be a potential target to attenuate the damage that triggers neuroinflammation after SAH.