Semaphorins 3A and synaptophysin P38 expression induced by status epilepticus in hippocampus of developing rat / 中华行为医学与脑科学杂志

ObjectiveTo observe Semaphorins-3A and synaptophysin P38 expression in hippocampus of developing rat induced by status epilepticus.Methods 320 SD rats were divided into four groups (P7,P14,P21 and P28) according to day -old after birth (7d,14d,21d and 28d).Rats in each group were randomly divided into model group (SE group) and saline control group (NS group).SE was induced by Pentylenetetrazol (PTZ).Semaphorins-3A and synaptophysin P38 expression were determined by immunohistochemical staining on 1d,7d,14d,21d and 28d after SE in hippocampal CA1 of rats.ResultsSemaphorins-3A-positive cells could be seen in the hippocampal granule cell layer in all rats.Semaphorins-3A expression tended to decrease with the increasing of day-age,especially in P7 group(91 552.68 ± 4664.69 ).No matter how day-age,Semaphorins-3A expression was similar to that in NS group and was obvious reduced in 7d after SE(56 938.84 ± 5688.47 ).Meanwhile P38 expression in P7-day-age rats had had been gradually increasing between 1 day and 14d (5413.18 ±48.77,6223.40±29.19,6902.94 ±78.51 ) and then stabilized gradually on 21d(7523.42 ± 62.94) after rats were tested.P38 expression in other day-age rat was relatively stable on the same level in physiological state.On the other hand P38 expression in the hippocampal CA1 region of P7,P14,P21 and P28 rats was significantly higher than that in normal rats between 1day and 28day after SE episode(P＜ 0.05 ),and reached a peak on 14 day(8408.35 ± 55.73 ).ConclusionSemaphorins-3A and synaptophysin P38 involved in hippocampal synaptic plasticity of rat in developing stage and epilepsy.

Ultrastructure of Spike Focus of Temporal Lobe Cortexes and Hippocampus in Patients with Protopathic Intractable Temporal Lobe Epilepsy / 中国康复理论与实践

@#Objective To observe the pathology in temporal lobe cortexes and hippocampus in protopathic intractable temporal lobe epileptics.Methods The cortexes of spike foci in temporal lobe and hippocampus were obtained from 9 cases with protopathic intractable temporal lobe epilepsy who accepted operation.The samples were observed under the transmission electron microscope.Results The ultrastructure changes in spike focus of temporal lobe cortexes are similar to those in hippocampus.It is common that neurons were pycnotic and decreased.Astrocytes were hydropic and degenerative.Gliosis were found in some cases.The number of synapses increased or decreased in different cases and positions.Blood-brain barriers were destroyed because foot processes of astrocytes around capillaries were edematous.Conclusion Neuronal loss,gliosis and synaptic reorganization which occur in epileptic hippocampus and maybe also in epileptic temporal lobe cortexes destroy the balance between excitatory and inhibitory neurotransmission.The abnormalities probably associate with protopathic intractable temporal lobe epileptic seizures.

Mossy fiber Synaptic Reorganization and the Pattern of Sprouting in the Pilocarpine Epilepsy Model

BACKGROUND: The purpose of this study is to evaluate the synaptic reorganization and pattern of mossy fiber sprouting as a pathologic mechanism of chronic seizure in pilocarpine epilepsy model through histological alterations of hippocampus. METHOD: Sprague-Dawley, a sensitively damaged by pilocarpine stimulation, served as a experimental group(n=20). And the same dose of saline injected rats were served as a control group(n=10). They were implanted depth electrode in the hippocampus by a stereotaxic surgery, and injected pilocarpine 300mg/Kg intraperitoneally. They produced status epilepticus and the survival rats were monitored by a video-EEG monitoring system whether the spontaneous recurrent seizures occurring for more than 4 weeks. If more than 3 times spontaneous recurrent seizures were identified, then the rat hippocampus was examined by light microscope. RESULT: The pilocarpine injected group produced acute limbic seizure and developed to status epilepticus. The survival rats(n=10) became to chronic epilepsy state after silent period of everage 16.5 days. H&E staining demonstrated that loss of hilar polymorphic cell with ischemic changes and destruction of CA1 with damages of pyramidal cells in hippocampal subfields. Timm stains showed mossy fiber synatic reorganization in the supragranular and intragranular layer of dentate gyrus and infrapyramidal layer of CA3 hippocampal subfieid in pilocarpine induce seizure rats. CONCLUSION: These results suggest that chronic seizures in the pilocarpine epilepsy model is largely due to mossy fiber synatic reorganization, a consequence of supragranular mossy fiber sprouting. But intragranular and infrapyramidal axonal sprouting might have parts of role in synaptic reorganization. Additional research is required to determine the various patterns of axonal sprouting.

Synaptic Reorganization of Dentate Mossy Fibers and Expression of Calcium Binding Proteins in Hippocampal Sclerosis of Temporal Lobe Epilepsy

This study was designed to identify expression of calcium-binding proteins and synaptic reorganizations of dentate mossy fibers in hippocampal sclerosis of human temporal lobe epilepsy. Hippocampal neuronal density was quantitively analyzed in temporal lobe epilepsy group (n=50) to investigate the degree of hippocampal sclerosis and it was compared with that of autopsy control (n=3). To verify the distribution of calcium-binding proteins in neurons of epileptic hippocampi, the parvalbumin (PV)-immunoreactive and calbindin-D28K (CB)-immunoreactive neurons were quantitively analyzed in each area of Ammon's horn by immunohistochemical stain. Also, to clarify synaptic reorganizations of the dentate mossy fibers, a part of each hippocampus was examined under light microscopy and transmission electron microscopy using Timm sulphide silver method. In epileptic hippocampi, severity of hippocampal sclerosis (HS) was graded four, which consisted of 3 cases with no HS, 6 mild HS, 12 moderate HS, and 29 severe HS. The hippocampal neuronal loss was most prominent in CA1, followed by CA4 and CA2. Expression of calcium-binding proteins was more prevalent in CA2 of all groups. The proportion of PV-immunoreactive neurons in CA1 and CA4 significantly increased in the moderate and severe HS group, whereas the proportion of CB-immunoreactive neurons did not correlated with the severity of HS. Timm granules were noted in inner molecular supragranular layer of dentate gyrus of epileptic hippocampi and they tended to increase in proportion along with the severity of hippocampal sclerosis. Transmission electron microscopy showed that supragranular Timm granules corresponded to synaptic terminals of mossy fibers. These results suggest that parvalbumin appears to have more protective effect against neuronal loss and that mossy fiber synaptic reorganization seems to play a major role in pathogenesis of hippocampal sclerosis of human temporal lobe epilepsy.

A Morphological Study of Synaptic Reorganization in Mossy Fibers of the Dentate Gyrus according to Hippocampal Sclerosis in Temporal Lobe Epilepsy: A Comparison of Intraoperative ECoG Findings for Tailored Resection

This study was carried out to identify synaptic reorganization by mossy fibers of epileptic dentate gyrus by Timm sulphide silver histochemistry and to investigate degree of synaptic reorganization according to both hippocampal sclerosis and epileptiform discharge in human temporal lobe epilepsy(TLE). The control group was composed of two hippocampal tissues obtained from autopsied brain without neurological abnormalities. TLE group was composed of thirteen hippocampal tissues obtained from surgically resected temporal lobe. Among thirteen hippocampal tissues, five specimens were obtained both of two areas of each hippocampus with or without prominent epileptiform discharges on electrocorticogram(ECoG) for tailored hippocampal resection. Hippocampal cell density was quantitatively analyzed in TLE group and compared with that of control group. A portion of hippocampal tissue was observed under light microscopic and transmission electron microscopes after development with Danscher method. The results were as follows : Hippocampal cell loss was noted in all TLE group. Hippocampal cell loss greater than 30% of control values was found in 12 cases and average hippocampal cell loss was 70%(range 39-88%). The remaining 1 case had 13% hippocampal cell loss. The supragranular Timm granules were noted in inner molecular layer of dentate gyrus and tended to significantly increase in proportion as severity of hippocampal sclerosis. Average of hippocampal cell loss in two areas of five hippocampal tissues with or without prominent epileptiform discharge on ECoG was 73.6%(range 53-90%) and 66.4%(range 50-86%), which showed statistically significant (p<0.05) difference between these two areas and the supragranular Timm granules also tended to increase in the hippocampal tissue with epileptiform discharge. On transmission electron microscope, there showed distinct supragranular Timm granules correspond to mossy fiber synaptic terminals. The results of this study demonstrated that mossy fiber synaptic reorganization seems to play a major role in pathogenesis of human TLE and the development of mossy fiber synaptic reorganization is closely related to severity of hippocampal sclerosis. The result also support the rationale for tailoring the extent of hippocampal resection by intraoperative acute recording(ECoG) according to individual pathophysiology.