Abstract # 2063 Paradoxical selenium effect induced by stress on LPS-induced sickness behavior in rats

Abstract

Sickness behavior is a motivational state that can be modulated by the environmental context. We induced sickness behavior in rats using lipopolysaccharides (LPS). Rats were treated with selenium in order to verify possible changes of sickness behavior expression. We exposed these rats to a restraint stress challenge and studied the paradigms: cure of the organism x preservation of the species x fight or flight. Studies of open-field behaviors, IL-1 beta and IFN-gamma serum levels, necropsy and histology were performed. LPS induced sickness behavior was evidenced by decreased motor/exploratory activity and increased proinflammatory immune mediators’ levels. Selenium supplementation did not exert beneficial effects on the sickness behavior symptoms. Therefore, selenium deficiency does not seem to be related to sickness behavior expression. LPS exposure did not affect behavior of rats in presence of stress. Thereby, sickness behavior was abrogated during stressor events to prioritize survival behaviors, such as fight or flight. Contrarily, the association of LPS, selenium, and stress induced sickness behavior even during stressor events and caused death of more than half rats of this experimental group. Necropsy revealed diffuse vascular damages in adrenals, liver, brain, and especially in the lungs. Adult respiratory distress syndrome secondary to circulatory shock was the cause-mortis. Thus, a paradox was seen in relation to selenium: instead of protection, it was toxic to rats that received LPS and stress. CAPES/Premio.