Circadian rhythms are behavioral and physiological changes that occur on a 24-hour cycle. The timing of these rhythms are set by a biological clock located in the hypothalamus of the brain which is set by the timing of light input. Abrupt changes in the light-dark cycle, such as an altered light-dark environment, leads to circadian disruption. Constant exposure to these conditions, such as in shift work, has been linked to diseases and stroke. Stroke is worsened by inflammation in the brain. Previous studies have shown that circadian disruption increases inflammation in the peripheral tissue, but its direct effect on the central nervous system is unknown. 24 male C57BL6 mice were subjected to 12 hour light and 12 hour dark cycles in either a constant or a weekly 6 hour advance. The mice were given brain injections of lipopolysaccharide (LPS) to induce an inflammatory response. The brain tissue was processed using PCR to probe for pro- and anti- inflammatory cytokines. We hypothesize that circadian disruption increases inflammatory response in the CNS after LPS.
