Peripheral Inflammation is accompanied by Cerebral Hypoperfusion in Mice

Area of Science:

• Neuroscience
• Vascular Biology
• Pain Research

Background:

• Chronic pain is linked to neuropsychiatric issues like anxiety and cognitive decline.
• Peripheral pain mechanisms are understood, but brain changes and behavioral effects remain unclear.
• Understanding the link between peripheral inflammation and brain alterations is crucial.

Purpose of the Study:

• To quantify cerebral blood perfusion changes using laser speckle contrast imaging (LSCI).
• To investigate the effects of unilateral peripheral inflammation induced by Complete Freund's adjuvant (CFA) in a murine model.
• To explore the relationship between peripheral inflammation and brain vascular changes.

Main Methods:

• Adult C57BL/6 mice (20 female, 24 male) received varying doses of CFA or saline in the hindpaw.
• Pain, working memory, and anxiety were assessed using von Frey, y-maze, zero maze, and open field tests.
• In vivo LSCI was used to measure cerebral blood perfusion in the parietal-temporal lobes post-inflammation.

Main Results:

• CFA administration induced local inflammation and reduced pain thresholds in the affected hindpaw.
• Animals exhibited anxiety-like behaviors in the zero maze.
• Cerebral hypoperfusion was observed in a dose-dependent manner, correlating with inflammation levels.

Conclusions:

• This study is the first to use LSCI to assess CFA-induced peripheral inflammation effects on cerebral blood perfusion.
• Peripheral tissue insult can lead to long-lasting brain plasticity through vascular mechanisms.
• Further research is needed to fully delineate these vascular pathways.