Deniz Sahin1, Canan Ugur Yilmaz2, Nurcan Orhan3, Nadir Arican4, Mehmet Kaya5, Candan Gürses6, Nurbay Ates1, Bulent Ahishali7. 1. Department of Physiology, Medical Faculty of Kocaeli University, Kocaeli, Turkey. 2. Department of Laboratory Animals Science, Institute of Experimental Medicine, Istanbul University, Istanbul, Turkey. 3. Department of Neuroscience, Institute of Experimental Medicine, Istanbul University, Istanbul, Turkey. 4. Department of Forensic Medicine, Istanbul Faculty of Medicine, Istanbul University, Turkey. 5. Koç University School of Medicine, Department of Physiology, Rumelifeneri Yolu, Sarıyer, 34450 Istanbul, Turkey. Electronic address: mehmetkaya@ku.edu.tr. 6. Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Turkey. 7. Department of Histology and Embryology, Istanbul Faculty of Medicine, Istanbul University, Turkey.
Abstract
PURPOSE: This study investigated the effects of cortical dysplasia (CD) on electrophysiology and blood-brain barrier (BBB) permeability in WAG/Rij rats with genetic absence epilepsy. METHODS: Pregnant WAG/Rij rats were exposed to 145cGy of gamma-irradiation on embryonic day 17 to induce CD. An electroencephalogram was recorded from cortices subdurally in the offspring of the pregnant animals. Horseradish peroxidase (HRP) was used as determinant of BBB permeability. RESULTS: A massive tissue loss in the cerebral cortex was seen in WAG/Rij rats with CD (p<0.05). There was a significant decrease in the number and duration of spike-and-wave discharges (SWDs) and an increase in the frequency of SWDs in the WAG/Rij rats with CD when compared with the properties of SWDs in intact WAG/Rij rats (p<0.01). Ultrastructurally, the accumulation of HRP reaction products in the cerebral cortex and thalamus of WAG/Rij rats was significantly higher than that of control values (p<0.01). The accumulation of HRP reaction products in the cerebral cortex and thalamus regions of WAG/Rij rats with CD increased and was higher than that of the control and WAG/Rij animals (p<0.01). CONCLUSION: In our study, we showed that number and duration of SWDs decreased and SWD frequency increased in WAG/Rij rats with CD, suggesting a shift in seizure pattern. The association of these alterations with significant loss of cortical thickness and increased BBB permeability to HRP tracer may represent a causal relation of the EEG abnormalities with cerebral structural changes in these animals.
PURPOSE: This study investigated the effects of cortical dysplasia (CD) on electrophysiology and blood-brain barrier (BBB) permeability in WAG/Rij rats with genetic absence epilepsy. METHODS: Pregnant WAG/Rij rats were exposed to 145cGy of gamma-irradiation on embryonic day 17 to induce CD. An electroencephalogram was recorded from cortices subdurally in the offspring of the pregnant animals. Horseradish peroxidase (HRP) was used as determinant of BBB permeability. RESULTS: A massive tissue loss in the cerebral cortex was seen in WAG/Rij rats with CD (p<0.05). There was a significant decrease in the number and duration of spike-and-wave discharges (SWDs) and an increase in the frequency of SWDs in the WAG/Rij rats with CD when compared with the properties of SWDs in intact WAG/Rij rats (p<0.01). Ultrastructurally, the accumulation of HRP reaction products in the cerebral cortex and thalamus of WAG/Rij rats was significantly higher than that of control values (p<0.01). The accumulation of HRP reaction products in the cerebral cortex and thalamus regions of WAG/Rij rats with CD increased and was higher than that of the control and WAG/Rij animals (p<0.01). CONCLUSION: In our study, we showed that number and duration of SWDs decreased and SWD frequency increased in WAG/Rij rats with CD, suggesting a shift in seizure pattern. The association of these alterations with significant loss of cortical thickness and increased BBB permeability to HRP tracer may represent a causal relation of the EEG abnormalities with cerebral structural changes in these animals.