Anesthesia and surgery induce age-dependent changes in behaviors and microbiota

Area of Science:

• Neuroscience
• Microbiology
• Gerontology

Background:

• The exact causes of postoperative delirium (POD) are unclear.
• Gut microbiota alterations are linked to neurological disorders.
• Age may influence susceptibility to POD.

Purpose of the Study:

• To investigate if anesthesia/surgery induces age-dependent gut microbiota dysbiosis.
• To examine the impact on brain IL-6 levels and mitochondrial function.
• To determine if these changes lead to delirium-like behavior in mice.

Main Methods:

• Age-dependent mouse model (9 vs. 18 months) undergoing abdominal surgery.
• Assessment of delirium-like behavior, gut microbiota (16S rRNA sequencing), brain IL-6, neuronal proteins (PSD-95, synaptophysin), and mitochondrial function.
• Intervention with Lactobacillus and probiotic treatments.

Main Results:

• Anesthesia/surgery caused distinct gut microbiota alterations, particularly reduced Lactobacillus levels, more pronounced in older mice.
• Older mice exhibited greater delirium-like behavior, elevated brain IL-6, reduced neuronal markers, and mitochondrial dysfunction post-surgery.
• Lactobacillus and probiotic treatments ameliorated surgery-induced changes.

Conclusions:

• Gut microbiota dysbiosis may contribute to the neuropathogenesis of POD.
• Age influences the gut-brain axis response to surgical stress.
• Probiotic interventions show potential for mitigating POD.