Long Term Mri Observations On Status-epilepticus Induced Neurodegeneration:A 7 Tesla Mr Study In A Rat Model

Backgroud and objects:Status epilepticus (SE) is a common brain insult that may lead to development of temporal lobe epilepsy (TLE) which is frequently characterized by hippocampal sclerosis, and other areas can also be involved. However, relatively limited information is available for dynamic changes about brain during disease progresssion. The present study aims to estimate these changes in acute, latent and chronic phases of epileptogenesis by using a long term (until 6 months) MR imaging follow up in the rat pilocarpine model that mimics most clinical and neuropathological features of TLE, and to evaluate possible neuroprotective effect of the drugs diazepam (DZP) and Phenobarbital(PB).Materials and Methods:The study was approved by the local Animal Welfare Committee.20 female Sprague Dawley rats were studied. Status epileticus (SE) was successfully induced in 14 rats by administration of pilocarpine. SE was interrupted with either DZP and PB (n=7, group PB) or DZP alone (n=7, group K0). MR scans were performed before (baseline), and 24 h,48h,1 week,6 weeks, 3 months, and 6 months after SE onset, to include acute and chronic phases of epileptogenesis. MR examinations were carried out on a 7 Tesla animal scanner. Image J software were adapt to measure the T2 relaxation time, FA value and ADC value, the region of interest(ROI) including retrosplenial parital cortex, retrosplenial temporal cortex, amygdale, piriform and enthorinal cortex, dorsal hippocampus, ventral hippocampus, posterior hippocampus, dorsal thalamus, ventral thalamus, substantial nigra and corpus callosum. Volumes of the hippocampus, CSF (cerebrospinal fluid) and intracranial vault were measured manually by using the free software ITK-SNAP. SPSS13.0 was performed to do the Statistical analysis. The T2 relaxation time, FA value and ADC value and hippocampal volume between cerebral hemispheres, different time points, and different groups were compared by using the two-tailed t-test.Results:There was no significant difference in T2 relaxation time, FA value and ADC value and hippocampal volume between cerebral hemispheres. The T2 relaxation time, FA value and volumes of the hippocampus, CSF and intracranial vault time dependence in different ROI showed similar in KO and PB group. However, the values of KO group changed more predominance than PB group. The ADC value time dependence appeared different between two groups.Conclusions:SE-induced neurodegeneration is a very long lasting process, which could be detected by MR T2mapping sequence, volume measurement and DTI. The combination of DZP and PB seems to have neuroprotective effects concerning brain injury.