OBJECTIVETo study the effect of a microRNA-132 antagonist on lithium-pilocarpine-induced status epilepticus (SE) in young Sprague-Dawley (SD) rats.

METHODSForty-five 3-week-old SD rats were randomly and equally divided into epilepticus model group, microRNA-132 antagonist group, and microRNA-132 antagonist negative control group. The young SD rat model of SE was established using lithium-pilocarpine. For the microRNA-132 antagonist group and the negative control group, pretreatment was performed 24 hours before the model establishment. Behavioral observation was performed to assess the latency of SE and success rate of induction of SE. The scale of Lado was used to evaluate the seizure severity. Electroencephalography (EEG) was used to assess the frequency and amplitude of epileptiform discharges. The mortality rate was calculated in each group.

RESULTSThere was no significant difference in the success rate of induction of SE between the three groups (P>0.05). Compared with the microRNA-132 negative control group and the epilepticus model group, the microRNA-132 antagonist group had significantly prolonged SE latency after model establishment (P<0.05), a significantly lower Lado score of seizure (P<0.05), significantly lower frequency and amplitude of epileptiform discharges on EEG (P<0.05), and a slightly reduced mortality rate.

CONCLUSIONSThe treatment with the microRNA-132 antagonist shows an inhibitory effect on the development and progression of lithium-pilocarpine-induced SE in young SD rats. The inhibition of microRNA-132 is likely to be a potential target or direction for drug treatment of SE.

Animals ; Electroencephalography ; Male ; MicroRNAs ; antagonists & inhibitors ; Pilocarpine ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Status Epilepticus ; chemically induced ; drug therapy

The present study is to explore the change process and distribution of phosphorylated DARPP-32 (p-DARPP-32) in rat brain including cortex, hippocampus and striatum and to further deduce whether p-DARPP-32 was possibly involved in epilepsy induced by repetitive low doses of pentylenetetrazol (PTZ). PTZ-induced epilepsy model in rat was established with 30 male SD rats randomly divided into 6 groups, control group and five trial groups [PTZ 1 h, PTZ 6 h, PTZ 24 h, PTZ 48 h and PTZ 72 h respectively, after onset of status epilepticus (SE)]. Immunohistochemistry and immunofluorescence double-labeling were used to detect the temporal time change and distribution of p-DARPP-32 expression and to analyze the coexpression of DARPP-32 and p-DARPP-32 in rat brain after the onset of PTZ-induced generalized SE. The results showed that there was a temporal time change of p-DARPP-32 expression in rat brain after the onset of SE. The number of p-DARPP-32-positive cells increased significantly and reached the peaks at the ends of 1 hour and 6 hours after the onset of SE, but decreased at the end of 24 hours. The moderate to strong p-DARPP-32-immunopositive neurons were observed in cortex, hippocampus and striatum, and located in cell cytoplasm and cell nucleus. Further immunofluorescence double-labeling revealed that denser colocalization of p-DARPP-32 and DARPP-32 in the neurons existed in the area mentioned above. Therefore, PTZ-induced SE may cause phosphorylation of DARPP-32 in rat brain. The temporal time change and distribution of p-DARPP-32 suggest that phosphorylation of DARPP-32 may be involved in PTZ-induced epilepsy in rat brain including cortex, hippocampus and striatum, and p-DARPP-32 may play a central role in the onset of SE.
Animals ; Cerebral Cortex ; metabolism ; Corpus Striatum ; metabolism ; Dopamine and cAMP-Regulated Phosphoprotein 32 ; metabolism ; Hippocampus ; metabolism ; Male ; Neurons ; metabolism ; Pentylenetetrazole ; Rats ; Rats, Sprague-Dawley ; Status Epilepticus ; chemically induced ; metabolism

OBJECTIVETo observe the changes in the learning and memory functions and the hippocampal expression of phosphorylated cAMP response element-binding protein (pCREB) in rats with status epilepticus and generalized nonconvulsive status epilepticus.

METHODSStatus epilepticus (SE) and generalized nonconvulsive status epilepticus (GNCSE) was induced by pentylenetetrazol kindling in SD rats, and the learning and memory function changes of the kindled rats were assessed by means of Morris water-maze test and Y-maze test with alternative electric stimulation. Immunocytochemistry was used for analysis pCREB protein expression in the hippocampus of the rats.

RESULTSIn Morris water-maze test, the rats with SE showed prolonged mean escape latency (P<0.05), shortened swimming time in the platform quadrant (P<0.05), and reduced number of times of platform crossing (P<0.05) in the short term after kindling. But these changes were reversed and became normal a month after the kindling (P>0.05). In the Y-maze test with alternative electric stimulation, the total error (TE) of SE rats increased significantly in the short term after epilepsy (P<0.05), but recovered the normal level a month after kindling (P>0.05). The GNCSE rats showed prolonged mean escape latency at only certain time periods (P<0.05) in the short term, but with swimming time in the platform quadrant and number of platform crossings similar to the control group (P>0.05). The short-term TE of GNCSE rats increased significantly (P<0.05), but in the long term, TE was similar to that in the control group (P>0.05). The expression of pCREB decreased significantly in SE group in comparison with the control group in the short term.

CONCLUSIONEpileptic seizures can lead to learning and memory function impairment in rats, and SE seems to cause greater impact than GNCSE on the learning and memory functions. pCREB might be involved in the pathophysiology of learning and memory deficit in epileptic rats.

Animals ; CREB-Binding Protein ; metabolism ; Hippocampus ; metabolism ; physiopathology ; Kindling, Neurologic ; Maze Learning ; Memory Disorders ; physiopathology ; Pentylenetetrazole ; Rats ; Rats, Sprague-Dawley ; Status Epilepticus ; chemically induced ; metabolism ; physiopathology

Adult ; Bed Rest ; adverse effects ; Coma ; chemically induced ; complications ; Encephalitis ; complications ; Female ; Humans ; Ossification, Heterotopic ; etiology ; Status Epilepticus ; complications ; drug therapy

OBJECTIVE: To investigate the relationship among mossy fiber axon sprouting(MFS), synaptic reorganization, and the alteration of expression of Eph A5 and ephrin A3 in the dentate gyrus in rats with pilocarpine-induced chronic temporal lobe epilepsy. METHODS: Mossy fiber sprouting and synaptic formation in rats were observed by Neo-Timm staining, after the acute status epilepticus and chronic spontaneous temporal lobe epilepsy induced by lithium-chloride and pilocarpine. In situ hybridization was used to detect ephrin A3 mRNA and an immunohistochemical staining was applied to determine Eph A5 protein. RESULTS: In entorhinal cortex, only Eph A5 mRNA and protein expressed, which significantly decreased on Day 7 after pilocarpine induced status epilepticus(P<0.01),and resumed to normal levels on Day 30 (P>0.05). In the dentate granule cells, ephrin A3 mRNA reduced obviously on Day 7 after pilocarpine-induced status epilepticus (P<0.01), and returned to normal levels on Day 30 (P>0.05). CONCLUSION The down-regulation of Eph A5 mRNA and protein in entorhinal cortex and dentate gyrus, and ephrin A3 mRNA in dentate gyrus after status epilepticus may be part of the endogenous molecular mechanism of mossy fiber sprouting to the inner molecular layer of dentate gyrus.
Animals ; Axons ; physiology ; Chromosome Pairing ; physiology ; Dentate Gyrus ; physiopathology ; Down-Regulation ; Ephrin-A3 ; biosynthesis ; Epilepsy, Temporal Lobe ; chemically induced ; metabolism ; physiopathology ; RNA, Messenger ; biosynthesis ; genetics ; Rats ; Receptor, EphA5 ; biosynthesis ; Status Epilepticus ; chemically induced ; metabolism ; physiopathology

OBJECTIVE: To investigate the role of neuropeptide Y(NPY) positive interneurons in the generation and compensation of temporal lobe epilepsy. METHODS: Pilocarpine-induced rat model was founded. Immunohistochemistry was used to observe the number changes and axonal sprouting of NPY interneurons at different time points in the hippocampus of rats. RESULTS: After lithium-chloride and pilocarpine administration, 92.9% rats were induced status epilepticus (SE) successfully, and the mortality rate was 19.2%. In the experimental group, the number of NPY positive neurons decreased in the hilus of the hippocampus, and was least on 7 d after the SE (P<0.01). In the chronic phase, the number of hilus NPY neurons partially recovered, but was still less than the number in the control group on 60 d after the SE (P<0.05). No evident changes of the number of NPY neurons existed in CA domains (P>0.05) except the loss of them in CA3 area on 7 d after the SE (P>0.05). Increased NPY positive fibers could be seen in the molecular layer of the dentate gyrus on 30 d after the SE. CONCLUSION NPY interneurons have different sensitivities to the injuries induced by seizures at different time points and domains. Loss of NPY interneurons plays an important role in the generation of temporal lobe epilepsy, while axonal sprouting of them may play a significant role in the compensation of temporal lobe epilepsy.
Animals ; Epilepsy, Temporal Lobe ; chemically induced ; pathology ; Hippocampus ; metabolism ; pathology ; Interneurons ; metabolism ; pathology ; Male ; Neuropeptide Y ; metabolism ; Pilocarpine ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Retrograde Degeneration ; pathology ; Status Epilepticus ; chemically induced ; pathology

OBJECTIVERefractory temporal lobe epilepsy (TCE) shows a unique type of hippocampal damage, referred to as hippocampal sclerosis. The mechanisms underlying drug-refractoriness in TCE are poorly understood, which may be connected with pharmacoresistance to antiepileptic drugs (AEDs). Some studies show that expression of the multidrug resistance gene (mdr1a and mdr1b) and p-glycoprotein encoded by mdr1a and mdr1b are high in the brain, especially in the hippocampus, and the expression may lead to reduction of AEDs concentration in the brain. But most of these studies focused on acute epileptic activity shortly after status epilepticus (SE), spontaneous seizures are seldom studied. The authors used a rat model of kainic acid induced spontaneous seizures to investigate expression of mdr1a and mdr1b mRNA, and explore whether topiramate (TPM) affects expression of mdr1a and mdr1b in the hippocampus.

METHODSSeizures were induced by intraperitoneal injection of 10 mg/kg kainic acid at postnatal day 28. Control rats were injected with sodium chloride. All rats were divided into 4 groups 1 week after spontaneous seizures developed: status epilepticus complicated with spontaneous seizures (SE, n = 8) group, status epilepticus complicated with spontaneous seizures treated with TPM (SE + TPM, n = 9) group, spontaneous seizures without status epilepticus (N-SE, n = 7) group, spontaneous seizures without status epilepticus treated with TPM (N-SE + TPM, n = 8) group, control (n = 7) group and control treated with TPM (control + TPM, n = 7) group. The treated rats were given therapeutic dose of TPM (25 mg/kg). All the rats were killed on the 42nd day of administration. The mdr1a and mdr1b mRNAs in the hippocampus were measured by RT-PCR.

RESULTSExpression of mdr1a and mdr1b mRNA in the hippocampus increased significantly in the SE + TPM group, SE group and N-SE + TPM group compared with control group (P < 0.001 or < 0.05). The mRNA in SE + TPM group increased significantly compared with the SE group, too (P < 0.01). The mdr1a and mdr1b mRNA expression in the hippocampus in control + TPM and N-SE groups did not change.

CONCLUSIONFrequent seizures, especially status epilepticus resulted in overexpression of mdr1a and mdr1b mRNAs in the hippocampus. The drug-refractoriness mechanism in TCE may be related to overexpression of mdr1a and mdr1b mRNAs. TPM could enhance the expression of mdr1a and mdr1b mRNAs in the hippocampus. Seizure activity and TPM are likely to be the main determinant in enhancing mdr1a and mdr1b mRNA expression in epilepsy.

ATP-Binding Cassette, Sub-Family B, Member 1 ; metabolism ; Animals ; Anticonvulsants ; pharmacology ; Fructose ; analogs & derivatives ; pharmacology ; Hippocampus ; metabolism ; Kainic Acid ; RNA, Messenger ; metabolism ; Rats ; Seizures ; chemically induced ; drug therapy ; metabolism ; Status Epilepticus ; drug therapy ; metabolism

OBJECTIVEThis study aimed to determine whether pentylenetetrazol-induced status epilepticus (SE) can induce dentate granule cell neurogenesis in the developing rat and the effect of MK-801, a noncompetitive antagonism of N-methyl-D-aspartate receptor (NMDAR), on neurogenesis.

METHODSTwo hundred and sixteen postnatal days 7, 14, 21 or 28 Sprague Dawley (SD) rats were involved in this study. Each age group consisted of 54 rats which were randomly assigned into a SE group, a SE + MK-801 group and a Normal control group (n=18 each). SE was induced by intraperitoneal injection of PTZ (80 mg/kg). The SE + MK-801 group was injected intraperitoneally with MK-801 (1 mg/kg) at 1 hr after SE episode. All rats were given 5-bromodeoxyuridene (BrdU) intraperitonealy to label newborn cells at 6, 13 and 27 days after seizures and then were sacrificed 24 hrs after BrdU injection. The immunohistochemistry method was used to measure the expression of BrdU, TuJl (betaIII tubulin), and glial fibrillary acidic protein (GFAP) in the dentate gyrus of hippocampus of rats.

RESULTSThe number of the BrdU positive cells in the SE group was significantly higher than in the age-matched normal controls at 7 and 14 days after SE episode (P <0.05 or 0.01). Approximately 82.5% and 80.3% of BrdU-labeled cells in the SE and the Control groups were co-expressed TuJ1 respectively. MK-801 treatment decreased the BrdU positive cells compared with the SE group at 7 and 14 days after SE seizures (P < 0.01). On the 28th day after SE episode there were no differences among the three groups for the BrdU positive cells.

CONCLUSIONSPTZ-induced SE can increase the dentate granule cell neurogenesis in the developing rat. NMDAR plays an important role in neurogenesis following seizures.

Animals ; Bromodeoxyuridine ; metabolism ; Dentate Gyrus ; drug effects ; physiopathology ; Dizocilpine Maleate ; pharmacology ; Female ; Glial Fibrillary Acidic Protein ; analysis ; Immunohistochemistry ; Male ; Pentylenetetrazole ; Rats ; Rats, Sprague-Dawley ; Status Epilepticus ; chemically induced ; physiopathology

OBJECTIVENeurogenesis in the dentate gyrus of hippocampus persists in brain of the immature and adult mammalian including human and it can be regulated by physiological and pathological events including nutritional status and seizures. The present study was designed to investigate the potential effects of malnutrition followed by status epileptics on hippocampal neurogenesis in the immature rat.

METHODSRat pups were divided into 4 groups: malnourished (M), nourished (N), malnourished plus seizures (MS) and nourished plus seizures (NS). The rat pups of group M and group MS were maintained on a starvation regimen from postnatal day 2 (P2) to P18. The status epilepticus of the rat pups in group MS and group NS was elicited by unilateral microinfusion of kainic acid (KA) into the amygdula at P15. Rat pups of the 4 groups were given bromodeoxyuridine (BrdU) intraperitoneally twice daily for 2 days beginning at P17. At P19, the rat pups were killed and the brains were processed for BrdU mitotic labeling combined with double-label immunohistochemistry using early neuron- or glia-specific markers TuJ1 (beta III tubulin) or GFAP (glial fibrillary acidic protein).

RESULTSThere were no significant differences in the latent time of seizure between group M and group N [(12.4 +/- 2.6) min vs. (12.1 +/- 2.9) min, P < 0.05]. Histological assessment did not reveal any evidence of hippocampal cell loss after status epilepticus in either group. BrdU-labeled cells were significantly higher in the rats of group MS (374 +/- 18) than group M (303 +/- 20), group NS (312 +/- 24) than group N (269 +/- 18), respectively (P < 0.01). There was also significant difference between group M and group N, group MS and group NS, respectively (P < 0.01). No significant difference was seen between the rats of group NS and group M (P > 0.05). Approximately 60% of BrdU-labeled cells coexpressed TuJ1, and 5% approximately 10% of those co-expressed GFAP.

CONCLUSIONEarly malnutrition do not alter KA seizure susceptibility and the behavioral manifestations of seizures at P15. Although malnutrition and status epilepticus can increase the proliferation of newly developed cells in the immature rat respectively, malnutrition followed by status epilepticus further increases this proliferation. Furthermore, most of newly developed cells differentiate into early neurons.

Animals ; Animals, Newborn ; Body Weight ; Bromodeoxyuridine ; metabolism ; Glial Fibrillary Acidic Protein ; analysis ; Hippocampus ; chemistry ; pathology ; Immunohistochemistry ; Malnutrition ; pathology ; Neurons ; chemistry ; pathology ; Rats ; Rats, Wistar ; Status Epilepticus ; chemically induced ; pathology ; Tubulin ; analysis

AIMSD rats were utilized for the purpose of the exploration of effects of status epilepticus (SE) on their emotional behavior, spatial learning and memory, and explorating its molecular mechanism.

METHODSForty maturity male SD rats, weighing (200 +/- 20) g were divided randomly and equally into SE group (SG) and normal control group (NG). The SG rats were induced by Pentylenetetrazole (PTZ) and the control animals received a saline (0.9%) solution. The change of emotional behavior in two groups were tested in elevated plus maze. Furthermore, Morris water maze was applied to evaluate the effects by SE on spatial learning and memory in rats. At the same time, N-methyl-D-aspartate (NMDA) receptor NR1 subunit mRNA in the hippocampus was determined by reverse transcription polymerase chain reaction (RT-PCR).

RESULTSIn elevated plus test, SE rats increased the times of visits as well as the time spent on the open arms of the elevated plus maze (P < 0.01). In Morris water maze, the mean escape latency for the SE rats looking for hidden platform in the place navigation test prolonged (P < 0.01). The efficiency of their search strategy was poor (P < 0.05). The swimming time in platform region and the percentage of their swimming time decreased (P < 0.01). The number of times they crossed the platform area decreased (P < 0.01). Meanwhile the expression of NR1 subunit mRNA in hippocampus was lower (P < 0.01).

CONCLUSIONThe experimental results showed that SE could result in the change of emotional behavior and damage of spatial learning and memory in rats. NR1 might be involved in the patho- and physiological process in causing these behavioral changes.

Animals ; Behavior, Animal ; drug effects ; Hippocampus ; drug effects ; metabolism ; Learning ; drug effects ; Male ; Memory ; drug effects ; Pentylenetetrazole ; adverse effects ; Rats ; Rats, Sprague-Dawley ; Receptors, N-Methyl-D-Aspartate ; metabolism ; Status Epilepticus ; chemically induced ; metabolism