Cytokine Content in the Hypothalamus and Hippocampus of C57Bl/6J Mice with Depressive-Like Behavior.

The content of pro- and anti-inflammatory cytokines in the hypothalamus, hippocampus, and blood serum of C57Bl/6J mice with depressive-like behavior induced by 20-day social stress was analyzed in 4 h after immune stimulation with LPS (250 μg/kg). These animals are characterized by a tendency to an increase in the blood content of IL-6 and a decrease in the level of IL-10. Changes in cytokine content in the brain of mice with depressive-like state developed under these conditions were observed only in the hippocampus: the levels of IL-1β, IL-6, TNFα, and IL-10 increased and the content of IFNγ decreased in comparison the corresponding parameters in the controls (not exposed to social stress) and aggressive animals.

Changes in Activity of Cysteine Cathepsins B and L in Brain Structures of Mice with Aggressive and Depressive-Like Behavior Formed under Conditions of Social Stress.

We studied activity of lysosomal cysteine proteases, cathepsins B and L, in brain structures (frontal cortex, caudate nucleus, hippocampus, and hypothalamus) of C57Bl/6J mice with aggressive and depressive-like behavior formed under conditions of chronic social stress (repeated experience of victories and defeats within 20 days). Mice with depressive-like behavior showed increased activity of cathepsin В in the hypothalamus and nucleus caudatus and increased activity of cathepsin L in the hippocampus compared to control animals not subjected to agonistic confrontations. In mice with aggressive behavior, protease activity in the studied brain structures was not changed.