TRAUMATIC INJURY INDUCES INTERLEUKIN-6 PRODUCTION BY HUMAN ASTROCYTES

The brain is being evaluated as a de novo source of cytokines. Because recent evidence indicates that interleukin-6 (IL-6) may influence blo od-brain barrier function and vascular permeability, we have sought to determine whether mechanical injury can directly induce in situ cereb ral IL-6 production. Adult human astrocyte cultures were subjected to mechanical injury by the in vitro method of fluid percussion barotraum a, developed in our laboratory. Serial supernatant samples were collec ted for 8 h and evaluated for IL-6 activity using a proliferation assa y employing the dependent B cell hybridoma cell line, B9. At optimum i njury, the IL-6 level became significantly (P < 0.0001, analysis of va riance) elevated from baseline 2 h after trauma and continued to incre ase over the observation period. Our study shows that following mechan ical injury human astrocytes produce IL-6, which may contribute to pos t-traumatic cerebrovascular dysfunction. Elucidating the precise role of intracerebral cytokines is essential to our understanding of the me chanism responsible for post-traumatic cerebrovascular dysfunction.