Role of IL-6 in cytokine-induced sickness behavior: a study with IL-6 deficient mice.
Interleukin-6 (IL-6) is synthesized and released in response to the cytokine inducer lipopolysaccharide (LPS) and IL-1, and acts as an endogenous pyrogen. Systemic administration of LPS and IL-1 to mice induces signs of sickness, including reduction of social exploration, immobility and body weight loss. To assess the role of IL-6 in the induction of sickness behavior, male IL-6-deficient mice (IL-6 -/-, Balb/cAn genetic background) were used and compared to IL-6 +/+ littermates. The depressing effects of intraperitoneal LPS (2.5 microg/mouse) and IL-1beta (1.0 microg/mouse) on behavior and change in body weight were more marked in IL-6 +/+ than in IL-6 -/- mice. The same difference was observed when mice were injected with LPS (5 ng/mouse) and IL-1beta (1 ng/mouse) into the lateral ventricle of the brain (i.c.v.). These results show that IL-6 released at the periphery and /or in the central nervous system plays a role in the behavioral response to LPS and IL-1.
Bluthé
R M
RM
INRA-INSERM U394, Institut François Magendie, Rue Camille St-Saëns, 33077 cedex, Bordeaux, France. rose-marie.bluthe@bordeaux.inserm.fr
Michaud
B
B
Poli
V
V
Dantzer
R
R
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D016207:Cytokines / Q000494:pharmacology*; D005106:Exploratory Behavior / Q000187:drug effects; D007276:Injections, Intraventricular; D007375:Interleukin-1 / Q000008:administration & dosage / Q000494:pharmacology; D015850:Interleukin-6 / Q000172:deficiency* / Q000502:physiology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D009043:Motor Activity / Q000187:drug effects; D012803:Sick Role
D016207:Cytokines; D007375:Interleukin-1; D015850:Interleukin-6; D008070:Lipopolysaccharides