EN
Subarachnoid hemorrhage (SAH) develops when extravasated arterial blood enters subarachnoid space and mixes with cerebrospinal fluid. This leads to numerous pathologies, including increased synthesis of proinflammatory cytokines, like interleukin-1β (IL-1β). Through broken blood-brain barrier, IL-1β may stimulate peripheral leukocytes. These peripheral mononuclear cells (PMC) may be an additional source of other cytokines and migrating to the brain they can enhance or reduce the pathologies resulting from SAH. We examined the effect of neutralization of IL-1β on secretion of TNF-α and IL-6 by PMCs in adult rats following SAH. SAH was produced by injection of 150 μL of autologous arterial blood into cisterna magna. In 50% of animals, IL-1β activity was inhibited by intracerebroventricular administration of anti-rat IL-1β antibodies. Control group consisted of sham-operated rats. Ninety minutes or 24 hrs following surgery, blood samples were collected from the extraorbital plexus and centrifuged to separate leukocyte subpopulations. Isolated PMCs (monocytes and lymphocytes) were cultured for 24 hrs and TNF-α and IL-6 concentrations in the supernatants were assessed with ELISA. SAH led to the increase of production of both TNF-α and IL-6 by PMCs. Neutralization of IL-1β activity significantly reduced the concentration of both cytokines 90 min as well as 24 hrs after SAH. The results indicate an important role of IL-1β in the activation of peripheral mononuclear cells in the course of subarachnoid hemorrhage.