Aged mice changed behavior after sepsis without broad inflammation
Researchers followed three-month-old and 18-month-old mice through seven days after sepsis; aged mice showed altered nesting and social behavior despite comparable illness severity.
Limit: Brain measurements on day eight could miss an earlier inflammatory contribution to behavioral changes
Young mice aged three months and aged mice aged 18 months underwent an animal experiment in which researchers induced sepsis, a life-threatening response to infection. They adjusted doses to produce comparable acute illness severity and assessed behavior through day seven. They examined the brains on day eight.
Aged mice showed changes in nest building and social behavior after acute illness had apparently resolved. These changes occurred without broad inflammation in the body or brain. Young mice maintained normal behavior despite elevated inflammation in both. The findings suggested that sepsis-induced inflammation alone did not account for the behavioral changes in aged mice.
Why it matters
Sepsis can leave older survivors with lasting difficulties in everyday activities. The researchers suggested that accumulated age-related vulnerabilities may limit the brain’s ability to cope with severe illness.
Caveats
Brain measurements on day eight could not rule out an earlier contribution from inflammation. The findings concerned mice during early recovery, not long-term outcomes in people.
The paper
Vanderbilt University
Brain, Behavior, and Immunity, Oct 14, 2026, Open access
