Magnetic resonance imaging under isoflurane anesthesia alters cortical cyclooxygenase-2 expression and glial cell morphology during sepsis-associated neurological dysfunction in rats

Background:Magnetic resonance imaging(MRI)of rodents combined with histol-ogy allows to determine what mechanisms underlie functional and structural brain changes during sepsis-associated encephalopathy.However,the effects of MRI per-formed in isoflurane-anesthetized rodents on modifications of the blood-brain bar-rier and the production of vasoactive prostaglandins and glia cells,which have been proposed to mediate sepsis-associated brain dysfunction,are unknown.Methods:This study addressed the effect of MRI under isoflurane anesthesia on blood-brain barrier integrity,cyclooxygenase-2 expression,and glial cell activation during cecal ligature and puncture-induced sepsis-associated brain dysfunction in rats.Results:Cecal ligature and puncture reduced food intake and the righting reflex.MRI under isoflurane anesthesia reduced blood-brain barrier breakdown,decreased cir-cularity of white matter astrocytes,and increased neuronal cyclooxygenase-2 immu-noreactivity in the cortex 24 hours after laparotomy.In addition,it annihilated cecal ligature and puncture-induced increased circularity of white matter microglia.MRI under isoflurane anesthesia,however,did not alter sepsis-associated perivascular cyclooxygenase-2 induction.Conclusion:These findings indicate that MRI under isoflurane anesthesia of rodents can modify neurovascular and glial responses and should,therefore,be interpreted with caution.