J Korean Soc Emerg Med.  2003 Mar;14(1):17-22.

Alteration of Interleukin-6 Levels in Brain Tissue and Serum of Rats after an Experimental Brain Contusion

• Jeon BM
• Kim YW
• Jeon BC

Abstract

PURPOSE
Cerebral contusion is often associated with delayed edema, ischemia, demyelination, and secondary impairment in the neurological function. Early prediction of the outcome for patients with diverse critical illnesses has long been a concern of intensive care unit physicians. Recently, the systemic release of host-derived inflammatory mediators has been used for prognosis assessment in patients with multiple infections, burn injury, and systemic infection. Experimental investigations have revealed the importance of free radicals and calcium currents in cellular damage. Also experimental injuries have caused an early production of cytokines. This study was undertaken to analyze the production of interleukin-6 in the brain and in plasma following a brain contusion.
METHODS
Sixty male Sprague-Dawley (SD) rats, each weighing 300-350 g were used in an experimental group following brain contusion, and 18 SD rats were used as a control group following a sham operation. Intracerebral IL-6 and plasma IL-6 were measured by using the ELISA method with a rat IL-6 kit at 3, 6, 24, 48, and 72 hours after the brain contusion. After contusion, the brains were fixed by perfusion via the carotid artery with 40% formaldehyde, glacial acetic acid, and 100% ethanol (1:1:8) at a flow rate of 25 ml/min and stained with hematoxylin and eosin for histologic examination.
RESULTS
Brain IL-6 levels increased to reach a maximum of 160.23 pg/ml, at 6 hour after brain trauma. Plasma IL-6 levels increased to 70.02 pg/ml at 3 hour following brain contusion.
CONCLUSION
The elevated brain IL-6 level in the injured rat does not seem to reflect a systemic inflammation. Although plasma IL-6 is detected in the sham-operated and the traumatized rats, the levels are too low to account for the increase observed in the brain cortex. This finding shows that the increase in brain IL-6 is related to the dynamics of brain contusion.

Keyword

Brain contusion; Brain; Plasma; IL-6

MeSH Terms

Acetic Acid
Animals
Brain Injuries*
Brain*
Burns
Calcium
Carotid Arteries
Contusions
Critical Illness
Cytokines
Demyelinating Diseases
Edema
Enzyme-Linked Immunosorbent Assay
Eosine Yellowish-(YS)
Ethanol
Formaldehyde
Free Radicals
Hematoxylin
Humans
Inflammation
Intensive Care Units
Interleukin-6*
Ischemia
Male
Perfusion
Plasma
Prognosis
Rats*
Rats, Sprague-Dawley
Acetic Acid
Calcium
Cytokines
Eosine Yellowish-(YS)
Ethanol
Formaldehyde
Free Radicals
Hematoxylin
Interleukin-6