Low-dose ketamine inhibits neuronal apoptosis and neuroinflammation in PC12 cells via α7nAChR mediated TLR4/MAPK/NF-κB signaling pathway

Ketamine is commonly used for sedation, analgesia and anesthetics. Much evidence has shown that it has an immune-regulatory effect. The cholinergic anti-inflammatory pathway mediated by α7nAChR is a prominent target of anti-inflammatory therapy. However, whether ketamine suppresses inflammatory levels in nerve cells by activating α7nAChR remains unknown. Lipopolysaccharide (LPS) was used to establish the neuroinflammation model in PC12 cells in vitro, and α7nAChR siRNA was transfected into PC12 cells 30 min before LPS to inhibit gene expression of α7nAChR. PC12 cells were stimulated with LPS for 24 h, and the indicators were detected at 2 h after GTS-21 and ketamine were added. The results showed that LPS increased the proportion of PC12 cells apoptosis, activated TLR4/MAPK/NF-κB signaling pathway, and increased the expression of interleukin-6 (IL-6), interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α). Ketamine reduced the ratio of early apoptosis and late apoptosis of PC12, inhibited the entry of P65 into the nucleus, decreased the activation of TLR4/MAPK/NF-κB and improved neuroinflammation. However, the ameliorating effects of ketamine on neuronal apoptosis and neuroinflammation were inhibited in the α7nAChRi group. This indicated that α7nAChR played a key role in the anti-inflammatory process of ketamine. Low-dose ketamine inhibited TLR4/MAPK/NF-κB by activating the α7nAChR-mediated cholinergic anti-inflammatory pathway, thereby producing the protective effect on neuronal apoptosis and neuroinflammation.