EN
Interleukin 6 (IL-6) is a cytokine playing an important pleiotropic role in the immune system. IL-6 is also involved in stress response, etiology of the age-related diseases and plays a role of mediator between the central nervous system and the immune system. To study effects of IL-6 on behavior during aging we examined aged (13 to 15 months) IL-6 deficient and wild type (WT) mice. Behavior was tested using the open field test, elevated plus maze test and registration of spontaneous activity in the individual home cages for 72 hours. These registrations showed that IL-6 deficient animals were less active than WT mice. The difference was more distinct during the dark phase. Interestingly, in the open field IL-6 deficient mice displayed higher locomotor activity than control WT mice and spent more time in the central part of the arena. In the elevated plus maze IL-6 deficient mice spent more time exploring open arms than WT mice. We conclude that IL-6 deficient aging animals show lower level of anxiety than WT control animals. After tests mice were perfused and brains were cut into 40 μm sections. Brain sections were immunohistochemically labeled for IL-6 and its receptor (IL-6R), also known as CD126. We found that cells immunopositive for both IL-6 and CD126 were present in the hippocampus and other brain structures. Supported by the National Science Center grant No 1577.