HSP60 Mediates NLRP3 Inflammasome-Dependent Microglial Pyroptosis Via the TLR4/MyD88/NF-κB Signaling Axis After Subarachnoid Hemorrhage

This study aims to elucidate the mechanism by which Heat Shock Protein 60 (HSP60) mediates microglial pyroptosis in the context of early brain injury (EBI) following subarachnoid hemorrhage (SAH), and to investigate the effects of HSP60 inhibition on EBI after SAH. A mouse subarachnoid hemorrhage (SAH) model was established using prechiasmatic cistern blood injection. In vitro, microglia were stimulated with 25 µmol/L oxyhemoglobin (OxyHB) to simulate the SAH pathological environment. In vivo, mice received 100 mg/kg Mizoribine, while in vitro, 80 µmol/L Mizoribine was used to suppress SAH-induced HSP60 upregulation. Techniques including Western blotting, immunofluorescence, immunohistochemistry, transmission electron microscopy, ELISA, modified Garcia neurological scoring, beam walking, brain water content measurement, Morris water maze, TUNEL staining, and Nissl staining were employed to systematically investigate the role of HSP60 inhibition in neuroinflammation and microglial pyroptosis after SAH. Compared to the sham group, both in vivo and in vitro studies with blinded, random sampling of six groups demonstrated a significant increase in HSP60 expression post-SAH. In vivo, 100 mg/kg Mizoribine alleviated blood-brain barrier disruption, cerebral edema, neuronal apoptosis/necrosis, and improved neurological deficits and cognitive impairment. In vitro, 80 µmol/L Mizoribine markedly attenuated microglial activation and pyroptosis, downregulated pro-inflammatory cytokines, and mitigated neuroinflammation. The upregulation of HSP60 after SAH promotes NLRP3 inflammasome assembly by activating the TLR4/MyD88/NF-κB signaling pathway, thereby inducing microglial pyroptosis and exacerbating the progression of early brain injury. Inhibition of HSP60 represents a potential therapeutic strategy for ameliorating EBI after SAH.