MRS METABOLIC MARKERS OF SEIZURES AND SEIZURE-INDUCED NEURONAL DAMAGE

Purpose: Proton magnetic resonance spectroscopy (MRS) was used to iden tify specific in situ metabolic markers for seizures and seizure-induc ed neuronal damage. Kainic acid (KA)-induced seizures lead to histopat hologic changes in rat brain. The protective effect of cycloheximide t reatment against neuronal damage caused by KA-induced seizures was stu died, using in Situ proton MRS imaging technique. Methods: Rats were p retreated with placebo or cycloheximide 1 h before KA injection. Rat b rains (n = 25) were scanned at the level of the hippocampus before, du ring, and 24 h after seizures. Spectra were recorded and the relative ratios of N-acetylaspartate (NAA), choline (cho), and lactate (Lac) to creatine (Cr) were calculated and compared between groups. Results: A significant increase in Lac ratios was observed in KA-treated rats du ring and 24 h after seizure onset and this increase was prevented by c ycloheximide pretreatment. NAA ratios were significantly higher during the ictal phase following KA treatment and this effect was not affect ed by cycloheximide pretreatment. Nissl staining confirmed previously reported prevention of KA-induced neuronal loss in CA3 and CA1 areas o f the hippocampus by cycloheximide pretreatment. Conclusions: Our resu lts suggest that in situ Lac increase is a marker of seizure-induced n euronal damage, whereas N-acetylaspartate (NAA) changes during and aft er status epilepticus may be a reflection of neuronal activity and dam age, respectively.