Effect of nectin-1 expression after being inhibited by lentivirus on epileptogenesis and mossy fiber sprouting / 中华神经医学杂志

Objective:To explore the effect of adhesion molecule nectin-1 expression on epileptic seizure and mossy fiber sprouting.Methods:(1) Adult male SD rats were randomly divided into control group ( n=6), empty vector group ( n=6) and lentivirus interfered group ( n=24), and rats in the lentivirus interfered group were further divided into 4 subgroups ( n=6) according to the time points of lentivirus injection (3, 7, 14 and 30 d after injection). The protein expression of nectin-1 in the hippocampus of rats was detected by Western blotting. (2) Another 12 male SD rats were randomly selected and divided into lentivirus epilepsy group ( n=6) and empty vector epilepsy group ( n=6). Lentivirus and empty lentivirus vector were injected into the hippocampus of the above two groups respectively, and then, pilocarpine epilepsy models were kindled; the behavior changes of these rats were recorded, and changes of mossy fiber sprouting in the hippocampus were observed by Timm staining. Results:(1) There were significant differences in hippocampal nectin-1 protein expressions in each group ( F=76.120, P=0.000); the nectin-1 expression in the 7, 14, and 30 d subgroups was significantly decreased as compared with that in the control group and empty vector group ( P<0.05). (2) The results of behavior changes showed that the times required for the lentivirus epilepsy group to be kindled successfully ([34.33±2.38] min) were significantly longer than those for the empty vector epilepsy group ([24.50±2.06] min, t=7.650, P=0.000). In terms of seizure level, the seizure level of rats in the lentivirus epilepsy group was significantly lower at each time point within one h modeling than that of rats in the empty vector epilepsy group ( P<0.05). After kindling, the time of spontaneous seizure appeared in the lentivirus epilepsy group was significantly longer than that in the empty vector epilepsy group, and the frequencies of spontaneous seizure in the lentivirus epilepsy group were significantly decreased as compared with those in the empty vector epilepsy group ( P<0.05). Timm staining scores in the lentivirus epilepsy group (3.500±0.224) were significantly lower than those in the empty vector epilepsy group (4.667±0.211, t=9.289, P=0.000). Conclusion:Inhibition of nectin-1 expression in hippocampal area of epileptic rats can delay the occurrence of epilepsy and reduce the frequencies of spontaneous seizures of epileptic rats, whose mechanism may be related to the reduction of nectin-1 in the formation of mossy fiber sprouting in abnormal neural circuits of hippocampal area.

Immature neurons born one week before pilocarpine-induced status epileptic exhibit aberrant integration at chronic stage after SE / 西安交通大学学报(医学版)

Objective To determine whether the integration of immature neurons born before status epilepticus (SE)can be disrupted by an epileptogenic insult.Methods Pilocarpine was used to induce SE in mice. At week 1 before induction,BrdU or retroviral vector expressing green fluorescent protein (RV-GFP)was used to label the newly born cells in the dentate gyrus (DG).At week 8 after SE,BrdU+Map2 or BrdU+NeuN double-labeling staining was carried out to visualize hilar basal dendrite or hilar ectopic migration.Virus-transduced GFP signals were used to identify the mossy fiber sprouting from the newly generated neurons.The number of cells with aberrant integrations was compared using unpaired Student's t-test.Results The percentage of newborn neurons with aberrant dendritic morphology was (20.8±8.4)% at week 8 after SE.The percentage of BrdU+NeuN double labeled cells ectopically migrated into the hilus was (15.9 ± 7.4)%.At week 8 after SE,the chronically epileptic mice showed many GFP+ processes in the IML with the same axonal appearance and small mossy fiber bouton-like structures as those seen in the hilus.The number of newborn neurons with aberrant integrations in SE mice wassignificantly increased when compared with the control mice (P <0.05).Conclusion These data demonstrate the existence of aberrant integrations-hilar basal dendrites,hilar ectopic migration and mossy fiber sprouting in the DG-generated cells born 1 week before an SE insult.

Immature neurons born one week before pilocarpine-induced status epileptic exhibit aberrant integration at chronic stage after SE / 西安交通大学学报(医学版)

Objective To determine whether the integration of immature neurons born before status epilepticus (SE)can be disrupted by an epileptogenic insult.Methods Pilocarpine was used to induce SE in mice. At week 1 before induction,BrdU or retroviral vector expressing green fluorescent protein (RV-GFP)was used to label the newly born cells in the dentate gyrus (DG).At week 8 after SE,BrdU+Map2 or BrdU+NeuN double-labeling staining was carried out to visualize hilar basal dendrite or hilar ectopic migration.Virus-transduced GFP signals were used to identify the mossy fiber sprouting from the newly generated neurons.The number of cells with aberrant integrations was compared using unpaired Student's t-test.Results The percentage of newborn neurons with aberrant dendritic morphology was (20.8±8.4)% at week 8 after SE.The percentage of BrdU+NeuN double labeled cells ectopically migrated into the hilus was (15.9 ± 7.4)%.At week 8 after SE,the chronically epileptic mice showed many GFP+ processes in the IML with the same axonal appearance and small mossy fiber bouton-like structures as those seen in the hilus.The number of newborn neurons with aberrant integrations in SE mice wassignificantly increased when compared with the control mice (P <0.05).Conclusion These data demonstrate the existence of aberrant integrations-hilar basal dendrites,hilar ectopic migration and mossy fiber sprouting in the DG-generated cells born 1 week before an SE insult.

Changes of mossy fiber sprouting and P-glycoprotein expression in the hippocampus of rat models of amygdala-kindling epilepsy / 中华神经医学杂志

Objective To explore the relationship between plasticity ofhippocampus neuronal morphology and pathogenesis of epilepsy by observing the changes of mossy fiber sprouting (MFS) and P-glycoprotein (P-gp) expression in the hippoeampus of rat models of amygdala-kindling epilepsy.Methods Ninety male Wistar rats were randomly divided into epilepsy model group (n=40),drug treatment group (n=40) and sham-operated group (n=10).Models of chronic epilepsy were established by stimulating the amygdale; rats in the drug treatment group were perfused antiepileptic drug levetiracetam into stomach [100 mg/(kg·d),twice daily].At different observation time points (1,2,4 and 8 weeks after the treatment),Timm staining was employed to observe the changes of MFS; immunohistochemical method was used to detect the dynamic changes of P-gp.Results (1) After the success of model making,abnormal MFS levels in the hippocampal CA3 transparent layer were noted; lowest MFS scores were noted in S1 subgroup,which showed no significant difference as compared with those in sham-operated group (P＞0.05); the MFS scores in S2,S4 and S8 subgroups increased gradually with a peak level at 8 weeks after inducement,which showed significant difference as compared with those in sham-operated group (P＜0.05).No significant differences on MFS grading scores were noted in the drug treatment group between each two time points (P＞0.05).(2) The P-gp expression in the epilepsy model group showed significant difference at different time points (P＜0.05); highest expression level was noted at one week after the surgery,and returned to normal at four weeks.However,the P-gp expression showed no significant difference in the drug treatment group between each two time points (P＞0.05),except for 1 week after treatment.Conclusion MFS is the important mechanism of chronic epilepsy,and P-gp is the product of epilepsy,which is the main reason of epilepsy drug resistance.

Effects of Pilocarpine-induced Seizures on the Neuronal Cell Death, Mossy Fiber Sprouting and Neurogensis in the Hippocampus of Mice / 체질인류학회지

Present study was performed to delineate the inter-relationship among neuronal death, mossy fiber sprouting (MFS) and neurogenesis in hippocampal formation of pilocarpine-treated mice. Status epilepticus was induced by intraperitoneal administration of 300 mg/kg pilocarpine in male ICR and C57BL/6 mouse. The severity of seizure was evaluated using 5 grades of Racine scales for first 4 hr after pilocarpine injection. Fluro-Jade C (FJC) staing, NeoTimm's staining and immunohistochemistry for BrdU were employed to evaluate neuronal cell death, MFS and neurogenesis, respectively. All animals in the present study induced seizures over grade 3 of Racine scale by pilocarpine injection. ICR mice show higher seizure severity (mean Racine scale; 4.37) than C57BL/6 mice do (mean Racine scale; 3.22), while the latency times for the first seizure over Racine scale grade 3 are from 15 min to 20 min and showed no difference between the 2 strains. In ICR mouse, numerous FJC-positive cells in hilus of hippocampus were detected at 4 h after pilocarpine injection, while they were not detected at that time in C57BL/6 mouse. The number of FJC-positive neuronal cells, which were densely found in the pyramidal layer of CA1, CA3 and hilus polymorphic regions of hippocampus, reached peak at 3 days after injection and then few cells were found at 7 days after injection in both strains. In control animals, BrdU positive cells in dentate subgranular layer which represent the hippocampal neurogenesis were more numerous in C57BL/6 than in ICR. The number of BrdU positive cells significantly increased at 2 days after pilocarpine injection and reached the peak at 8 days after injection and returned to control level at 15 day after injection in both strains. The percent increase of the BrdU positive cell was more prominent in ICR mouse. MFS was found at 2 weeks after the injection and the intensity of MFS was getting strong at 4 weeks after injection. There was no differences in MFS grading between 2 strains. These results suggest that there are some inter-relationships among the seizure severity, hippocampal neuronal cell death and hippocampal neurogenesis, but they don't have any significant relationships with the mossy fiber sprouting from dentate granule cells.

Comparison of Behavioral and Histological Changes between Pilocarpine-Induced Temporal Epilepsy Model and Pentylenetetrazole Kindling Absence Model in Rats / 中国康复理论与实践

@#ObjectiveTo investigate and compare the behavioral changes, neuron loss of hippocampus and mossy fiber sprouting between pilocarpine-induced status epilepticus (SE) model and pentylenetetrazole (PTZ) kindling model in rats.MethodsAfter two different epilepsy models were made, Vedio was adopted to observe the behavioral changes. Nissl staining and Neo-timms' staining were separately used to observe and compare the neuron loss of hippocampus and mossy fiber sprouting in the dentate gyrus (DG) at different time points during epileptogenisis.ResultsNo recurrent spontaneous seizure, no neuron loss and no mossy fiber sprouting were found in PTZ kindling model; whereas obvious neuron loss was found in CA1, CA3 of hippocampus and hilus of DG, and mossy fiber sprouting were found in pilocarpine model in parallel with recurrent spontaneous seizures. ConclusionPTZ kindling model resembles absence epilepsy in human, while pilocarpine-induced status epilepticus model resembles chronic temporal epilepsy in human. Neuron loss and mossy fiber sprouting may play an important role in epileptogenisis. Pilocarpine-induced epilepsy model can be regarded as an ideal chronic temporal epilepsy model.

Interference effect of Kangxianzengzhi capsule on hippocampal mossy fiber sprouting in epileptic rat kindled by pentylenetetrazol / 中华中医药杂志

To explore the interference effect of Kangxianzengzhi(KXZZ) capsule on hippocampal mossy fiber sprouting in epileptic rat kindled by pentylenetetrazol.Methods: Epileptic rat models were established by pentylenetetrazol(PTZ) kindling method.All rats were divided into six groups: KXZZ high-does group,KXZZ middle-does group,KXZZ low-does group,valproate magnesium group, model group and normal group randomly.Then the hippocampal mossy fiber sprouting was monitored by Timm stain method.Results: Mossy fiber sprouting was obvious in the hippocampal CA3 section and the molecular layer of dentate syrus in model group.Compared with normal group,the percent of sprouting density in model group was higher(P

The Effect of MK 801 on the Development of Brain Damage, Spontaneous Recurrent Seizures and Mossy Fiber Sprouting in the Pilocarpine Induced Status Epilepticus Animal Model / 대한소아신경학회지

PURPOSE: We investigated the effect on MK 801 on the development on brain damage, spontaneous recurrent seizures and mossy fiber sprouting in the pilocarpine induced status epilepticus animal model. Methods: Fifty two adult Sprague Dawley male rats(180-240gm) were studied under ketamine/xylazine(87mg/13mg/kg, IP) anesthesia and were implanted at the F3, P3, F4, P4 areas for recording EEG. With a single intraperitoneal(IP) administration of pilocarpine hydrochloride(360mg/kg), 70% developed status epilepticus(SE). When SE was not induced within 1 hour after injection of pilocarpine, the second dose of pilocarpine(175mg/kg, IP) was injected, with 86.6% of success. Results: All studied animals were divided into two large groups, one group was treated with NMDA receptor antagonist, the other was control group. The mean duration of SE was 62.00+/-6.80 minutes in the MK 801(1mg/kg, IP, 30 minutes after SE) treated group, and 61.10+/-7.37 minutes in the control group without any signigicant differences(P>0.05). Neuronal loss(necrosis dominantly) was observed at CA1 and CA3 areas in the control group, with more loss after 6 weeks than 24 or 72 hrs specimens. However, there was no neuronal loss in MK 801 treated group. The protective effect of MK 801 for neuronal injury suggested the glutamate receptor activation was involved in the neuronal injury induced by repeated seizure attack. Spontaneous recurrent seizures(SRS) were observed 70% of animals in the control group, but there were no SRS observed in the MK 801 treated group. The mean scores of mossy fiber sprouting were significantly higher in the control group(2.05+/-0.47) than MK 801 treated group(0.4+/-0.32)(P<0.05). Conclusion: These results suggested that SRS and mossy fiber sprouting were associated with NMDA receptor activation, and NMDA receptor activation had a key role in the epilepsy development.

Observation on the Hippocampal Mossy Fiber Sprouting After Hypoxic-Ischemic Neuronal Loss in Juvenile and Mature Rat Brain / 대한소아신경학회지

PURPOSE: Reorganization of mossy fiber terminals in the supragranular layer of the dentate has been found in hippocampi of human epileptics and animal models by Timm staining. Many studies have provided evidence that mossy fiber sprouting is strongly associated with neuronal loss. But the question of whether cell loss is necessary for stimulation of mossy fiber sprouting is remained to be answered. In this present study, we evaluated whether hippocampal mossy fiber sprouting is induced in damaged hippocampus of the rats exposed to hypoxic-ischemic insults in juvenile and adult period. METHODS: At ages of 4-5 weeks and 2 months, the experimental rats were received procedure of right carotid artery unilateral ligation under anesthesia. After 3 hours of the recovery period, they were placed in an airtight 2000ml chamber and exposed to a 8% oxygen-92% nitrogen mixture delivered at 5 liter/min for 90 minutes (juvenile) and 50 minutes (adult). After the recovery period, The animals were returned to cages and housed with controls. 2 weeks later, rats of the control and hypoxic-ischemia group were anesthetised and then perfused with sodium sulfide solusion and fixed. 40micrometer (for Timm stain) and 5micrometer (for H & E stain) coronary brain sections were obtained, stained with Timm method and H < E stain for the observation of the neuronal loss and supragranular Timm granules in the hippocampi. RESULTS: Light microscopic examination of the brains from hypoxic-ischemic animals demonstrated ischemic changes of variable degrees in the hippocampal hilar and pyramidal cell layers. No supragranular mossy fiber sprouting were found in hippocampi of juvenile and adult rats with hypoxic-ischemic damages. CONCLUSION: These results implicated that hippocampal mossy fiber sprouting is not induced in the experimental hypoxic-ischemic encephalopathy of juvenile and adult rats, although cellular loss is found in hippocampus. Neuronal loss might be not necessary for the development of mossy fiber sprouting.

Expression of c-Fos Protein and Character of Mossy Fiber Sprouting in Hippocampus of Rat with Febrile Seizures / 实用儿科临床杂志

Objective To explore the expression of c-Fos protein and character of mossy fiber sprouting(MFS) in hippocampus of rat with febrile seizures(FS).Methods Thirty-six 21-day-old male Sprague-Dawley rats were randomly divided into FS group,febrile control(FG) group and normal control(NG) group.FS was established by hyperthermal bath.Immune histochemistry and(Timm′s) staining were used to examine the expression of c-Fos protein in CA1 region and MFS in CA3 region of hippocampus.Results Excessive expression of c-Fos protein presented in the hippocampal CA1 region of FS group.The surface area percentage of c-Fos protein of FS group[(2.26?0.23)%] was higher than that of FG group[(1.08?0.19)%] and NG group[(0.71?0.14)%],there were significant difference between FS group and the other two groups(?~2=10.48 P

Morphologic changes of hippocampal formation in rat of kainate-induced temporal lobe epilepsy / 第三军医大学学报

Objective To study the pathologic changes of hippocampus during the model development and explore the mechanism of epileptogenesis by observing the morphologic changes of hippocampal formation in rat of kainate-induced chronic temporal lobe epilepsy (TLE). Methods Thirty Wistar rats were injected of Kainic acid at dose of 2 ?g/20 ?l into the lateral cerebral ventricle under the guidence of stereotactic technique to make a epileptic focus, and subgrouped under acute phase, silent period and chronic phase. Another 10 rats received normal saline as controls. The rats were killed at 1 day, 15 day and 6 months after epileptic model establishment, and the hippocampus was taken out for HE staining, TUNEL staining, Timm’s staining, NSE staining. Results By cell counting, the neuron loss mainly occurred in acute phase, worst in CA3 and CA4, moderate in CA1 and CA2, and no loss in the dentate gyrus. The cell apoptosis in hippocampal structure was detected by TUNEL staining. Timm’s staining showed that mossy fiber began sprouting in silent period and increased continuously. Conclusion The morphologic changes of hippocampal formation in rat of kainate-induced TLE is mainly the neuron loss and the glia hyperplasy.