General anesthesia leads to a loss of consciousness and an unrousable state in patients. Although general anesthetics are widely used in clinical practice, their underlying mechanisms remain elusive. The potential involvement of nonneuronal cells is unknown. Microglia are important immune cells in the central nervous system (CNS) that play critical roles in CNS function and dysfunction. We unintentionally observed delayed anesthesia induction and early anesthesia emergence in microglia-depleted mice. We found that microglial depletion differentially regulates neuronal activities by suppressing the neuronal network of anesthesia-activated brain regions and activating emergence-activated brain regions. Thus, microglia facilitate and stabilize the anesthesia status. This influence is not mediated by dendritic spine plasticity. Instead, it relies on the activation of microglial P2Y12 and subsequent calcium influx, which facilitates the general anesthesia response. Together, we elucidate the regulatory role of microglia in general anesthesia, extending our knowledge of how nonneuronal cells modulate neuronal activities.
Perioperative neurocognitive disorders (PNDs) are common neurological complications after anesthesia in the elderly. Protein tyrosine phosphatase non-receptor type 2 (PTPN2) regulates signal transducer and activator of transcription protein 3 (STAT3) signaling to control inflammation in certain organs, but its role in PNDs remains unknown. Herein, we constructed a PND model in 18-month-old rats by treating them with sevoflurane. PND rats developed neuroinflammation, along with a significant decrease in PTPN2 expression and a rise in STAT3 phosphorylation in the hippocampus. Ptpn2 overexpression alleviated the behavioral disorders of PND rats, ameliorated neuronal injury, inhibited neuroinflammation, inflammasome activation, microglial activation, and microglial phenotype switching. Similar results were observed in sevoflurane-treated HMC3 microglia with PTPN2 overexpression, while PTPN2 silencing showed the opposite results. Additionally, PTPN2 seems to be a target of T-box transcription factor 2 (TBX2). These results contribute to the evidence supporting the idea that PTPN2 is a regulatory factor in PND progression.