coriaria-lactone and Epilepsy--Temporal-Lobe

Hypoxia-inducible factor-1α (HIF-1α) is thought to mediate pharmacoresistance in tumor by inducing Pgp overexpression. We aimed to investigate the expression of HIF-1α and MDR1/P-glycoprotein in refractory epilepsy, to explore the correlation of HIF-1α with epilepsy multidrug resistance. We collected hippocampus and mesial temporal lobe (MTL) cortex of refractory mesial temporal lobe epilepsy (mTLE) patients that underwent surgery, and established a pharmacoresistant TLE rat model kindled by coriaria lactone. We used real-time quantitative PCR (RQ-PCR) and western blot to investigate expression of HIF-1α and MDR1 in hippocampus and MTL/entorhinal cortex. We found that the expression of HIF-1α and MDR1, at both mRNA and protein levels, were up-regulated in hippocampus and MTL cortex of mTLE patients compared with the control cortex (all P < 0.05), and increased in hippocampus and entorhinal cortex of kindled rat model versus the control group (all P < 0.05). These results demonstrated the overexpression of HIF-1α and MDR1/Pgp in hippocampus and MTL/entorhinal cortex of mTLE patients and the pharmacoresistant TLE rat model. HIF-1α may have a regulatory effect on MDR1 expression in refractory epilepsy, which is probably consistent with MDR mechanism in tumor.

Topics: Adult; Animals; Anticonvulsants; ATP Binding Cassette Transporter, Subfamily B; ATP Binding Cassette Transporter, Subfamily B, Member 1; Brain Neoplasms; Case-Control Studies; Cerebral Hemorrhage; Convulsants; Disease Models, Animal; Drug Resistance, Multiple; Entorhinal Cortex; Epilepsy, Temporal Lobe; Female; Genes, MDR; Hippocampus; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Kindling, Neurologic; Lactones; Male; Middle Aged; Nerve Tissue Proteins; Random Allocation; Rats; Rats, Sprague-Dawley; Up-Regulation; Young Adult

One of the major challenges in developing novel therapeutics for human epileptic disorders derives from the limitation of knowledge of the processes by which epilepsy is generated (epileptogenesis). Furthermore, the inability to obtain human samples at the early stage of epilepsy hinders studies designed to further understand epileptogenesis. Thus, an effective animal model is critical for studies investigating this process. The purpose of this study was to establish a new primate kindling model of temporal lobe epilepsy (TLE) as an animal model of epileptogenesis. Here, repeated injections of Coriaria lactone (CL) at a subthreshold dose elicited partial seizures that culminated in secondarily generalized tonic-clonic seizures. The sequence of events and features of the behaviors observed in this model simulated those observed in human TLE. Electroencephalogram monitoring revealed the temporal lobe origins of the epileptiform potentials, which were consistent with the behavioral changes observed. A total of 7 rhesus monkeys (78%) were kindled with a median of 48 (41 to 60) CL injections. Both the seizure-induction and mortality rates were dose-dependent. A CL injection at 1.50mg/kg showed the lowest animal mortality rate (0%) and the highest seizure-induction rate (100%). Extensive kindling by CL injections with a median of 97 injections (overkindling) subsequently resulted in the recurrence of spontaneous seizures in rhesus monkeys with frequency patterns that were similar to those observed in human TLE. In addition, rhesus monkeys subjected to large numbers of kindling stimuli displayed mitochondrial damage and astrocyte activation in a pattern that was similar to the neuropathological changes characteristic of human TLE. Thus, a kindling TLE model in rhesus monkeys representing a primate animal model of epileptogenesis was established for the first time using repeated intramuscular injections of Coriaria lactone. This model was easily and efficiently performed and resulted in behavioral, electrographical, and anatomical characteristics of human TLE. Thus, this model might be used in future investigations of the mechanisms involved in the epileptogenesis of TLE and in the development of new antiepileptic drugs.

Topics: Analysis of Variance; Animals; Brain; Chi-Square Distribution; Disease Models, Animal; Dose-Response Relationship, Drug; Electroencephalography; Epilepsy, Temporal Lobe; Glial Fibrillary Acidic Protein; Kindling, Neurologic; Lactones; Macaca mulatta; Male; Mitochondria

Glutamate receptor 5 (GluR5) plays a role as an excitatory regulator of synaptic transmission and plasticity; however, its exact role in the pathological mechanism underlying epilepsy is not fully known. We investigated GluR5 expression in resected brain tissues from humans with temporal lobe epilepsy (TLE) and from a macaque model of Coriaria lactone-induced TLE. GluR5 was upregulated in the hippocampus, but not in the temporal neocortex, of patients with TLE compared to the control group. In contrast, GluR5 expression in the hippocampus of macaques treated with Coriaria lactone was not upregulated compared to the control. In addition, mossy fiber sprouting in the hippocampus of TLE patients was correlated with GluR5 upregulation, whereas mossy fiber sprouting was not observed in the macaque model lacking GluR5 upregulation, suggesting that GluR5 function is mainly associated with mossy fiber sprouting.

Topics: Adolescent; Adult; Animals; Blotting, Western; Disease Models, Animal; Epilepsy, Temporal Lobe; Female; Hippocampus; Humans; Lactones; Macaca; Male; Microscopy, Electron; Middle Aged; Mossy Fibers, Hippocampal; Neurons; Polymerase Chain Reaction; Receptors, Kainic Acid; Temporal Lobe; Up-Regulation; Young Adult

To explore the relationship between merlin and hippocampal sclerosis of temporal epilepsy.. The kindling model of epilepsy induced by corciaria lactone (CL) in rats was used. The expression of merlin in neuron of cortex of temporal lobe and hippocampal CA1 region was observed using immunohistochemistry method. Comparison of the amount of neuron with expression of merlin in the two locations was made between the kindled group, non-kindled group and control group.. The expression of merlin in neuron of cortex of temporal lobe and hippocampal CA1 region of the kindled group was higher than the expression of the other two groups (P < 0.05), and there was no significant difference between the expression in the non-kindled group and that in the control group (P > 0.05). The expression of merlin in glial cell of the same region of all groups was seldom seen.. The super-expression of merlin in neuron of cortex of temporal lobe and hippocampal CA1 region of the kindled rats may be involved in the process of neuronal apoptosis and hippocampal sclerosis.

Topics: Animals; Disease Models, Animal; Epilepsy, Temporal Lobe; Hippocampus; Immunohistochemistry; Kindling, Neurologic; Lactones; Male; Neurofibromin 2; Rats; Rats, Sprague-Dawley; Temporal Lobe

Overexpression of the multiple drug resistance gene 1 (MDR1) was quantified in brain tissue from Coriaria lactone (CL)-kindled Sprague-Dawley (SD) rats after treatment with lamotrigine (LTG) or topiramate (TPM) and compared with that found in rats treated with carbamazepine (CBZ) and valproate (VPA).. Twenty-five CL-kindled SD rats were randomized into five groups (n = 5 for each group) to receive once-daily feeding of CBZ, VPA, TPM, and LTG as the monotherapy equivalent of maximum human adult dosage, or normal saline (NS control) for 1 month. The expression of P-gp in brain tissues of all rats was quantified by using an image analysis and measuring system (Image Pro-plus 4.0). Mean area and mean integrated optical density (mean IOD) of P-gp expression were calculated. In addition, the changes in seizure severity were analyzed via video-camera monitoring.. A significant decrease in the number and duration of seizures with antiepileptic drug (AED) treatment was observed in the TPM and LTG groups. The mean area and mean IOD of P-gp expression were highest in the CBZ group and next highest in the VPA group; much lower values were measured in the TPM and LTG groups, and the lowest in the NS control group (p < 0.05).. TPM and LTG significantly inhibited seizures in this CL model. The expression of P-gp was not significantly increased by TPM or LTG treatment in this study.

Topics: Animals; Anticonvulsants; ATP Binding Cassette Transporter, Subfamily B, Member 1; Brain; Carbamazepine; Disease Models, Animal; Drug Resistance; Epilepsy, Temporal Lobe; Fructose; Gene Expression; Genes, MDR; Humans; Immunohistochemistry; Kindling, Neurologic; Lactones; Lamotrigine; Male; Random Allocation; Rats; Rats, Sprague-Dawley; Topiramate; Triazines; Valproic Acid

The aim of this study was to develop a new animal model of pharmacoresistant temporal lobe epilepsy (TLE) by repeated intramuscular injection of Coriaria lactone (CL) at subthreshold dosages and to explore the mechanisms that might be involved.. Healthy male Sprague-Dawley rats (n = 160) were randomized into four groups during the kindling process: three groups (n = 50 for each group) received CL injection at subthreshold dosages (1.25, 1.5, and 1.75 mg/kg, respectively), and ten received normal saline (NS) injection as a control group. The maximal human adult dosage of carbamazepine (CBZ), valproate (VPA), and phenytoin (PHT) was administered as monotherapy to different groups of kindled rats for 1 month (n = 20 for each group). Changes in EEG recording, seizure number, intensity (expressed as grade 1-5 according to Racine stage), and duration, including spontaneous seizures during different interventions, were compared. The expression of P-170, a multiple drug resistance gene (MDR1) encoding P-glycoprotein, was measured in brain samples from different groups of experimental rats by using an image analysis and measurement system (ImagePro-Plus 4.0).. A total of 70 (46.7%) rats were fully kindled with a median of 15 (seven to 20) CL injections. Electrocorticogram (ECoG) including hippocampal (EHG) monitoring revealed the temporal lobe origins of epileptiform potentials, which were consistent with the behavioral changes observed. Spontaneous seizures occurred with frequency and diurnal patterns similar to those of human TLE. The antiepileptic drugs (AEDs) tested lacked a satisfactory seizure control. The maximal P-170 expression was in the kindled rats with AED treatment; the next highest was in the kindled rats without AED intervention. Nonkindled SD rats with CL injection also had increased P-170 expression compared with control SD rats.. The study provided a simple and stable animal TLE kindling model with pharmacoresistant properties. The pharmacoresistance observed in the kindled rats to CBZ, VPA, and PHT at maximal human adult dosages together with the increased P-170 expression was a distinct feature of this model. This model might be used in further investigations of the mechanisms involved in pharmacoresistant TLE and for developing new AEDs.

Topics: Animals; Anticonvulsants; ATP Binding Cassette Transporter, Subfamily B; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Resistance; Drugs, Chinese Herbal; Electroencephalography; Epilepsy, Temporal Lobe; Gene Expression; Glycoproteins; Hippocampus; Humans; Injections, Intramuscular; Kindling, Neurologic; Lactones; Male; Phytotherapy; Rats; Rats, Sprague-Dawley; Temporal Lobe