Dexmedetomidine ameliorates postoperative cognitive dysfunction by inhibiting Toll-like receptor 4 signaling in aged...

Area of Science:

• Neuroscience
• Pharmacology
• Immunology

Background:

• Postoperative cognitive dysfunction (POCD) is a common complication, particularly in aged individuals undergoing surgery.
• The exact molecular mechanisms underlying POCD remain incompletely understood.
• Neuroinflammation, involving microglia activation and cytokine release, is implicated in POCD pathogenesis.

Purpose of the Study:

• To investigate the molecular mechanisms by which dexmedetomidine (DEX) improves POCD.
• To examine the effect of DEX on inflammatory responses in microglia cells.
• To evaluate DEX's impact on spatial memory and hippocampal neuroinflammation in aged mice after surgery.

Main Methods:

• BV2 microglia cells were treated with DEX, lipopolysaccharide (LPS), or DEX followed by LPS.
• Pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) and signaling pathways (TLR4, NF-κB) were assessed.
• Aged mice underwent partial hepatectomy, with spatial memory evaluated and hippocampal tissues analyzed.

Main Results:

• LPS induced significant increases in pro-inflammatory cytokines and TLR4/NF-κB expression in BV2 cells.
• DEX pretreatment suppressed LPS-induced cytokine release and TLR4/NF-κB activation.
• Aged mice showed impaired spatial memory post-surgery, which was attenuated by DEX pretreatment.

Conclusions:

• DEX pretreatment inhibits neuroinflammation by suppressing the TLR4-NF-κB signaling pathway.
• DEX demonstrates potential therapeutic effects in mitigating POCD in aged populations.
• Targeting the TLR4-NF-κB pathway with DEX may be a viable strategy for preventing POCD.