Objectives: Gram-negative infections and control infusion of recombinant cytokines in human have been shown to induce sickness behavior characterized by fever, prolong sleep, decreased food and water intake, reduced mobility, depression, and anxiety. Therefore, the present study was undertaken to investigate the effect of bioflavonoid quercetin in lipopolysaccharide (LPS)-induced sickness behavior.
Materials and methods: Wistar albino rats were divided into six groups (n=6). Three groups received vehicle and two doses of quercetin (2 and 25 mg/kg, i.p.) respectively for 2 weeks before being challenged with LPS (1 mg/kg, i.p). One group received vehicle for 2 weeks and was challenged with saline on day 15. The per se effect of quercetin (2 and 25 mg/kg, i.p.) was also seen after 2 weeks of dosing. LPS-induced sickness behavior in rats was quantified by measuring time in social exploration, anxiety, food and water consumption, and weight loss. Levels of cytokines (TNF-α, IL-1β, and IL-6) and oxidative stress in rat brain were also analyzed.
Results: Quercetin (2 and 25 mg/kg) administration significantly (P<0.05) attenuated LPS-induced sickness behavior by modulating cytokines production as well inhibiting LPS-induced oxidative stress.
Conclusions: Adequate intake of dietary flavonoids (like quercetin) may help promote recovery from sickness behavior.
Keywords: Lipopolysaccharide; Quercetin; oxidative stress; polyphenols; sickness behavior.