Hippocampal gene expression signature following inflammation in epileptic mice

We used a systemic inflammatory challenge in animals with chronic mesial temporal lobe epilepsy to identify novel molecular pathways involved in seizure regulation. Mice were first rendered epileptic by a single intrahippocampal injection of kainic acid (KA). After a period of two-three weeks, mice developed spontaneous seizures and then received a single intraperitoneal injection of lipopolysaccharide (LPS) to mimic systemic inflammation, or saline as a control. Gene expression analysis by microarrays was then performed on hippocampal RNA samples extracted 4 and 24 hours after LPS or saline treatment (n=3 samples per treatment group). Inflammation-induced gene expression in the epileptic mouse hippocampus was measured at 4 and 24 hours after intraperitoneal injection of lipopolysaccharide (LPS; L5886, Sigma; from Salmonella enterica, serotype abortus equi; 100 micrograms/kg in PBS) or saline (SAL). Three animals per treatment group were analyzed at each time point (4 or 24 hours).