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Updated: Dec 16, 2025
A Mouse Model of Orthopedic Surgery to Study Postoperative Cognitive Dysfunction and Tissue Regeneration
Published on: February 27, 2018
Blocking Kv1.3 potassium channels prevents postoperative neuroinflammation and cognitive decline without impairing
Ieng K Lai1, Martin Valdearcos2, Kazuhito Morioka3
1Center for Cerebrovascular Research, Department of Anesthesia and Perioperative Care, University of California, San Francisco, CA, USA.
Background:
Postoperative cognitive decline (PCD) requires microglial activation. Voltage-gated Kv1.3 potassium channels are involved in microglial activation. We determined the role of Kv1.3 in PCD and the efficacy and safety of inhibiting Kv1.3 with phenoxyalkoxypsoralen-1 (PAP-1) in preventing PCD in a mouse model.
Methods:
After institutional approval, we assessed whether Kv1.3-deficient mice (Kv1.3-/-) exhibited PCD, evidenced by tibial-fracture surgery-induced decline in aversive freezing behaviour, and whether PAP-1 could prevent PCD and postoperative neuroinflammation in PCD-vulnerable diet-induced obese (DIO) mice. We also evaluated whether PAP-1 altered either postoperative peripheral inflammation or tibial-fracture healing.
Results:
Freezing behaviour was unaltered in postoperative Kv1.3-/- mice. In DIO mice, PAP-1 prevented postoperative (i) attenuation of freezing behaviour (54 [17.3]% vs 33.4 [12.7]%; P=0.03), (ii) hippocampal microglial activation by size (130 [31] pixels vs 249 [49]; P<0.001) and fluorescence intensity (12 000 [2260] vs 20 800 [5080] absorbance units; P<0.001), and (iii) hippocampal upregulation of interleukin-6 (IL-6) (14.9 [5.7] vs 25.6 [10.4] pg mg-1; P=0.011). Phenoxyalkoxypsoralen-1 neither affected surgery-induced upregulation of plasma IL-6 nor cartilage and bone components of the surgical fracture callus.
Conclusions:
Microglial-mediated PCD requires Kv1.3 activity, determined by genetic and pharmacological targeting approaches. Phenoxyalkoxypsoralen-1 blockade of Kv1.3 prevented surgery-induced hippocampal microglial activation and neuroinflammation in mice known to be vulnerable to PCD. Regarding perioperative safety, these beneficial effects of PAP-1 treatment occurred without impacting fracture healing. Kv1.3 blockers, currently undergoing clinical trials for other conditions, may represent an effective and safe intervention to prevent PCD.
Insights
Voltage-gated Kv1.3 channels drive microglial activation in postoperative cognitive decline (PCD). Inhibiting Kv1.3 with phenoxyalkoxypsoralen-1 (PAP-1) effectively prevented PCD and neuroinflammation in mice without impairing fracture healing.
Area of Science:
- Neuroscience
- Immunology
- Pharmacology
Background:
- Postoperative cognitive decline (PCD) is linked to microglial activation.
- Voltage-gated Kv1.3 potassium channels play a role in microglial activation.
Purpose of the Study:
- To investigate the role of Kv1.3 in PCD.
- To evaluate the efficacy and safety of phenoxyalkoxypsoralen-1 (PAP-1) in preventing PCD.
Main Methods:
- Assessed PCD in Kv1.3-deficient mice and diet-induced obese (DIO) mice treated with PAP-1.
- Measured aversive freezing behavior, hippocampal microglial activation, and neuroinflammation (IL-6).
- Evaluated PAP-1's impact on peripheral inflammation and fracture healing.
Main Results:
- PAP-1 prevented the decline in freezing behavior in DIO mice.
- PAP-1 reduced microglial activation and IL-6 levels in the hippocampus.
- PAP-1 did not affect plasma IL-6 or fracture healing.
Conclusions:
- Microglial-mediated PCD necessitates Kv1.3 activity.
- PAP-1 effectively blocks Kv1.3, preventing PCD and neuroinflammation.
- Kv1.3 inhibitors show potential as safe interventions for PCD prevention.
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