Norepinephrine infusion increases interleukin-6 in plasma and cerebrospinal fluid of brain-injured rats.

Abstract

BACKGROUND:

Significantly increased plasma and CSF IL-6 levels reflect underlying tissue damage following clinical and experimental traumatic brain injury (TBI). Catecholamines, used under clinical conditions to maintain adequate cerebral perfusion pressure, induce a sustained IL-6 release. Thus an additional elevation in IL-6 could aggravate brain edema in the acute posttraumatic phase. We studied the changes in plasma and cerebrospinal fluid (CSF) IL-6 levels 4 and 24 hours after experimental TBI and assessed possible time-dependent effects of norepinephrine infusion on IL-6 and brain edema.

MATERIAL/METHODS:

Paired plasma and CSF IL-6 measured at 4 and 24 hours following TBI (n=10) were compared to levels in non-traumatized rats (n=5). In a placebo-controlled trial, 20 brain-injured male Sprague-Dawley rats were randomized to receive norepinephrine or NaCl for 90 minutes at 4 or 24 hours after TBI. Plasma IL-6 was measured before, during, and after the infusion period. One hour after stopping the infusion, CSF IL-6 and hemispheric swelling were determined.

RESULTS:

During the first posttraumatic day, plasma and CSF IL-6 levels were significantly increased compared to non-traumatized rats, reaching the highest values at 24 hours (p<0.05). Norepinephrine infusion significantly increased plasma IL-6 at 7 and 27 hours after TBI; IL-6 was significantly elevated in CSF only at 7 hours (p<0.05). Brain edema was not aggravated.

CONCLUSIONS:

The norepinephrine-induced increase in plasma and CSF IL-6 suggests that concomitant norepinephrine administration needs to be considered when interpreting systemic and local changes in IL-6 levels in TBI patients.

• Authors: John F Stover, Oliver W Sakowitz, Britta Schöning, Stefan Rupprecht, Stefan N Kroppenstedt, Ulrich W Thomale, Christian Woiciechowsky, Andreas W Unterberg
• Journal: Medical science monitor : international medical journal of experimental and clinical research (Med Sci Monit) Vol. 9 Issue 10 Pg. BR382-8 (Oct 2003) ISSN: 1234-1010 [Print] United States
• PMID: 14523327 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Interleukin-6
• Sodium Chloride
• Norepinephrine

Topics

• Animals
• Brain Injuries (blood, cerebrospinal fluid)
• Edema
• Interleukin-6 (blood, metabolism)
• Male
• Norepinephrine (pharmacology)
• Rats
• Rats, Sprague-Dawley
• Sodium Chloride (pharmacology)
• Time Factors