Abstracts

Rationale: Status Epilepticus (SE) is a neurological emergency that must be treated quickly. Changes that occur in the brain following SE may depend on the cause and/or duration of SE. Proton Magnetic Resonance Spectroscopy (MRS) is a useful tool in assessing ongoing changes in the brain following SE. This test can be performed several times in the same animal at different time points.Methods: Postnatal day 15(P15) rats were exposed to SE induced by flurothyl (FE) or kainic acid (KA). FE SE was induced by one hour exposure in a FE chamber. KA SE was induced by IP administration of KA inducing SE that lasts over 18 hours. MRS was performed on all rats at two time points: 3 days and 5 weeks after SE. N-acetyl aspartate (NAA), and creatine (Cr) levels in the hippocampus, thalamus, and frontal cortex of these rats was assessed and compared to control rats that were not exposed to KA or FE. Results: Rats with FE induced SE had a significantly lower NAA/Cr ratio in hippocampus, cortex, and thalamus compared to both controls and rats with KA induced SE. 5 weeks after SE there was no longer a significant difference between the groups. FE rats showed a significant increase in NAA/Cr from the initial scan to the follow up scan in hippocampus (p=.0128), and thalamus (p=.0034). In contrast, KA rats showed a significant decrease in NAA/Cr in the cortex (p=.0037) and thalamus (p=.0416). Conclusions: The ratio of NAA/Cr is considered a metabolic marker reflecting the functional status of neurons and axons in the brain, with a decrease indicating neuronal or axonal loss or dysfunction. FE SE causes acute changes in the brain. However, these changes are transient and NAA/Cr recovers within 5 weeks. KA did not produce any acute changes in the brain but was associated with long term changes, in the absence of discernable cell loss.