Neuroinflammation and cognitive function in aged mice following minor surgery

Area of Science:

• Neuroscience
• Immunology
• Gerontology

Background:

• Postoperative cognitive dysfunction (POCD) is a common concern in elderly patients after surgery.
• Surgical trauma activates the peripheral innate immune system, releasing inflammatory mediators.
• Aged individuals exhibit heightened neuroinflammation and microglial priming, leading to exaggerated responses.

Purpose of the Study:

• To investigate if surgical trauma induces neuroinflammation and cognitive impairment in aged mice.
• To compare the neuroinflammatory and cognitive responses to surgery in adult versus aged mice.

Main Methods:

• Adult and aged mice underwent minor abdominal surgery.
• Hippocampal cytokine levels (IL-1beta mRNA) were measured 24 hours post-surgery.
• Working memory and cognitive flexibility were assessed using a Morris water maze reversal learning task.

Main Results:

• Aged mice showed significantly increased IL-1beta mRNA levels in the hippocampus post-surgery.
• Adult mice did not exhibit neuroinflammation after surgery.
• Aged mice demonstrated a trend towards perseveration, suggesting reduced cognitive flexibility, but no severe cognitive impairment.

Conclusions:

• Minor surgery elicits an exaggerated neuroinflammatory response in aged mice.
• The observed neuroinflammation in aged mice did not lead to significant cognitive impairment in the Morris water maze task.
• Age-related differences in immune response to surgical stress are evident at the neuroinflammatory level.