| Objective: To demonstrate spontaneous seizures without seizure-provoking events,intracranial electroencephalogram(EEG) and learning and memory ability in rats with malformation of cortical development. Methods : Time-pregnant Sprague-Dawley rats were irradiated on day E17 with 175 c Gy(2), 195 c Gy(2), 215 c Gy(2) or untreated(2). Their litters(group L, group M, group H, group N) were randomly divided into three groups.one group was measured the learning and memory ability by Morris water maze(MWM).We recorded intracranial EEG the second group by RM6240 C multi-channel physiological signal acquisition system. The other was underwent long-term video monitoring by internet protocol camera.In the end, All animals were killed and their brains processed for histopathological study. Results: The behavior of all animals was different between day and night. All animals were more active at night. Spontaneous seizures were recorded in seven in fifty animals in model group. Seizures Were most generally seen during the night(79.0%).Spontaneous seizures were recorded in three in five animals in group M. Spontaneous seizures were recorded in two in five animals in group L and H. The difference of in seizure average duration between group H and the other group was statistically significant. The seizure frequency of group M(1.33/24h) was the highest compared with the other group. The average escape latencies were significantly predicted by the day of testing, and whether the animals had been exposed to radiation. Compared with the first day of testing, animals in all groups were likely to find the platform more quickly on Day 4(P<0.05). At the same training day,the average escape latencies was significantly dose-dependent, the number of crossing the plate was no significant difference among radiated groups, the distance in the target quadrant(%total) was significant difference between group H and the others(P<0.01). The average escape latencies of all animals on Day 4 at three phases were significant different. The number of crossing the plate was no significant difference among three phases. The distance in the target quadrant(%total) of group H was lower than others at immature and adolescent rats. Spikes were most frequently found in the rats at the group M and less frequently seen in the animals at the group L and group H(P<0.01).Little spike was found in any of the control animals. No significant difference was found among frontal lobe,parietal lobe and hippocampus spikes of the rats in each group. No significant difference was seen regarding the lateralization of the interictal activity. Histopathological studies shown a dose-dependent damage at the cortex, subcortex, hippocampus, corpus callosum of the rats with MCD compared with the control group. conclusion:Pregnant rats X-ray irradiated injury on embryonic day 17 could result in an ideal animal model simulating human MCD. This method is cheap, easy, cognition impaired earlier, higher rate of spontaneous seizures.The group with 195 c Gy shown serious mental retardation, the highest rate of intracranial spikes and spontaneous seizures. |
PDF Full Text Request