Epileptic Mice Research Articles

On-demand low-frequency stimulation for seizure control: efficacy and behavioural implications.

Mesial temporal lobe epilepsy (MTLE), the most common form of focal epilepsy in adults, is often refractory to medication and associated with hippocampal sclerosis. Deep brain stimulation represents an alternative treatment option for drug-resistant patients who are ineligible for resective brain surgery. In clinical practice, closed-loop stimulation at high frequencies is applied to interrupt ongoing seizures, yet has (i) a high incidence of false detections; (ii) the drawback of delayed seizure-suppressive intervention; and (iii) limited success in sclerotic tissue. As an alternative, low-frequency stimulation (LFS) has been explored recently in patients with focal epilepsies. In preclinical epilepsy models, hippocampal LFS successfully prevented seizures when applied continuously. Since it would be advantageous to reduce the stimulation load, we developed a protocol for on-demand LFS. Given the importance of the hippocampus for navigation and memory, we investigated potential consequences of LFS on hippocampal function. To this end, we used the intrahippocampal kainate mouse model, which recapitulates the key features of MTLE, including spontaneous seizure activity and hippocampal sclerosis. Specifically, our online detection algorithm monitored epileptiform activity in hippocampal local field potential recordings and identified short epileptiform bursts preceding focal seizure clusters, triggering hippocampal LFS to stabilize the network state. To probe behavioural performance, we tested the acute influence of LFS on anxiety-like behaviour in the light-dark box test, spatial and non-spatial memory in the object location memory and novel object recognition test, as well as spatial navigation and long-term memory in the Barnes maze. On-demand LFS was almost as effective as continuous LFS in preventing focal seizure clusters but with a significantly lower stimulation load. When we compared the behavioural performance of chronically epileptic mice to healthy controls, we found that both groups were equally mobile, but epileptic mice displayed an increased anxiety level, altered spatial learning strategy and impaired memory performance. Most importantly, with the application of hippocampal LFS before behavioural training and test sessions, we could rule out deleterious effects on cognition and even show an alleviation of deficits in long-term memory recall in chronically epileptic mice. Taken together, our findings may provide a promising alternative to current therapies, overcoming some of their major limitations, and inspire further investigation of LFS for seizure control in focal epilepsy syndromes.

Reduced Cholecystokinin-Expressing Interneuron Input Contributes to Disinhibition of the Hippocampal CA2 Region in a Mouse Model of Temporal Lobe Epilepsy.

A significant proportion of temporal lobe epilepsy (TLE) patients experience drug-resistant seizures associated with mesial temporal sclerosis, in which there is extensive cell loss in the hippocampal CA1 and CA3 subfields, with a relative sparing of dentate gyrus granule cells and CA2 pyramidal neurons (PNs). A role for CA2 in seizure generation was suggested based on findings of a reduction in CA2 synaptic inhibition (Williamson and Spencer, 1994) and the presence of interictal-like spike activity in CA2 in resected hippocampal tissue from TLE patients (Wittner et al., 2009). We recently found that in the pilocarpine-induced status epilepticus (PILO-SE) mouse model of TLE there was an increase in CA2 intrinsic excitability associated with a loss of CA2 synaptic inhibition. Furthermore, chemogenetic silencing of CA2 significantly reduced seizure frequency, consistent with a role of CA2 in promoting seizure generation and/or propagation (Whitebirch et al., 2022). In the present study, we explored the cellular basis of this inhibitory deficit using immunohistochemical and electrophysiological approaches in PILO-SE male and female mice. We report a widespread decrease in the density of pro-cholecystokinin-immunopositive (CCK+) interneurons and a functional impairment of CCK+ interneuron-mediated inhibition of CA2 PNs. We also found a disruption in the perisomatic perineuronal net in the CA2 stratum pyramidale. Such pathologic alterations may contribute to an enhanced excitation of CA2 PNs and CA2-dependent seizure activity in the PILO-SE mouse model.SIGNIFICANCE STATEMENT Impaired synaptic inhibition in hippocampal circuits has been identified as a key feature that contributes to the emergence and propagation of seizure activity in human patients and animal models of temporal lobe epilepsy (TLE). Among the hippocampal subfields, the CA2 region is particularly resilient to seizure-associated neurodegeneration and has been suggested to play a key role in seizure activity in TLE. Here we report that perisomatic inhibition of CA2 pyramidal neurons mediated by cholecystokinin-expressing interneurons is selectively reduced in acute hippocampal slices from epileptic mice. Parvalbumin-expressing interneurons, in contrast, appear relatively conserved in epileptic mice. These findings advance our understanding of the cellular mechanisms underlying inhibitory disruption in hippocampal circuits in a mouse model of spontaneous recurring seizures.

Mechanism of Robo1 in the pentylenetetrazol-kindled epilepsy mouse model.

The neural network hypothesis is one of the important pathogenesis of drug-resistant epilepsy. Axons guide molecules through synaptic remodeling and brain tissue remodeling, which may result in the formation of abnormal neural networks. Therefore, axon guidance plays a crucial role in disease progression. However, although Robo1 is one of the important components of axon guidance, the role of Robo1 in epilepsy remains unclear. In this study, we aimed to explore the mechanism of Robo1 in epilepsy. Male adult C57BL/6 mice were intraperitoneally injected with pentylenetetrazol to establish an epilepsy model. Lentivirus (LV) was given via intracranial injection 2 weeks before pentylenetetrazol injection. Different expressions of Robo1 between the control group, LV-mediated Robo1 short hairpin RNA group, empty vector control LV group, and normal saline group were analyzed using Western blot, immunofluorescence staining, Golgi staining, and video monitoring. Robo1 was increased in the hippocampus in the pentylenetetrazol-induced epilepsy mouse model; lentiviral Robo1 knockdown prolonged the latency of seizure and reduced the seizure grade in mice and resulted in a decrease in dendritic spine density, while the number of mature dendritic spines was maintained. We speculate that Robo1 has been implicated in the development and progression of epilepsy through its effects on dendritic spine morphology and density. Epileptic mice with Robo1 knockdown virus intervention had lower seizure grade and longer latency. Follow-up findings suggest that Robo1 may modulate seizures by affecting dendritic spine density and morphology. Downregulation of Robo1 may negatively regulate epileptogenesis by decreasing the density of dendritic spines and maintaining a greater number of mature dendritic spines.

The sigma-1 receptor-TAMM41 axis modulates neuroinflammation and attenuates memory impairment during the latent period of epileptogenesis.

Therapy in the latent period is favorable for retarding the process of epileptogenesis. Recently, we have discovered that the activated sigma-1 receptor (Sig-1R) attenuates the hippocampus pathological injury and memory impairment in the latent period of epileptogenesis. But the molecular mechanism needs further investigation. PRE-084 was utilized as a research tool to highly selectively activate Sig-1R in epileptic mice. After the treatment of PRE-084, the pro-inflammatory cytokines, neuropathological traits, and the level of mitochondrial translocator assembly and maintenance 41 homolog (TAMM41) in the hippocampus were examined. The mode in which the Sig-1R interacts with TAMM41 was explored. The role of TAMM41 in the protecting effect of PRE-084 was established. PRE-084 inhibited the growth of pro-inflammatory cytokines, reduced the formation of gliosis, alleviated neuronal damage in the hippocampus, and attenuated memory impairment in the latent period of epileptogenesis. The protein level of TAMM41 decreased in the hippocampi of epileptic mice and increased in the PRE-084-treated mice. The Sig-1R bound with TAMM41 directly, maintaining the stability of TAMM41. Knockdown of TAMM41 reversed the protective effect of PRE-084, and overexpression of TAMM41 exhibited a similar protective action to that of PRE-084. We presented the concept of the "sigma-1 receptor-TAMM41 axis" and proposed that augmenting this axis can attenuate neuroinflammation and memory impairment in the process of epileptogenesis.

A novel hydrogen sulfide donor reduces neuroinflammation and seizures by activating ATP-sensitive potassium channels

Epilepsy is a common neurological disorder worldwide. Hydrogen sulfide (H2S) has been found to have anti-seizure effects. However, its mechanism remains to be explored. In the present study, we showed that a novel H2S donor attenuated neuroinflammation by up-regulating ATP-sensitive potassium channel (KATP) expression to reduce seizures. The novel H2S donor significantly reduced the expression of TNF-α and increased the expression of IL-10 in LPS-treated BV2 cells and the hippocampus of pilocarpine-induced epileptic mice. The modulatory effects of the H2S donor on inflammatory cytokines were prevented by glibenclamide, a common KATP channels blocker. The H2S donor promoted the expression of KATP channel subunits SUR2 and Kir6.1 in LPS-treated BV2 cells and the hippocampus of pilocarpine-induced epileptic mice. In addition, the H2S donor reduced the electroencephalography amplitude of hippocampal epileptic waves and reduced seizures in pilocarpine-induced epileptic mice, which were also attenuated by glibenclamide. These results indicated that the novel H2S donor reduced seizures and regulated microglial inflammatory cytokines by activating KATP channels, which may provide a prospective therapeutic strategy for the anti-seizure effects of H2S donor.

A CMOS-based highly scalable flexible neural electrode interface.

Perception, thoughts, and actions are encoded by the coordinated activity of large neuronal populations spread over large areas. However, existing electrophysiological devices are limited by their scalability in capturing this cortex-wide activity. Here, we developed an electrode connector based on an ultra-conformable thin-film electrode array that self-assembles onto silicon microelectrode arrays enabling multithousand channel counts at a millimeter scale. The interconnects are formed using microfabricated electrode pads suspended by thin support arms, termed Flex2Chip. Capillary-assisted assembly drives the pads to deform toward the chip surface, and van der Waals forces maintain this deformation, establishing Ohmic contact. Flex2Chip arrays successfully measured extracellular action potentials ex vivo and resolved micrometer scale seizure propagation trajectories in epileptic mice. We find that seizure dynamics in absence epilepsy in the Scn8a+/- model do not have constant propagation trajectories.

Notopterygium incisum Root Extract (NRE) Alleviates Epileptiform Symptoms in PTZ-Induced Acute Seizure Mice.

Epilepsy is a common neurological disorder affecting more than 70 million people worldwide. Despite numerous efforts on new antiepileptic drugs, approximately one-third of epilepsy patients suffer from uncontrolled seizures. It leads to serious psychosocial consequences, cognitive problems, and decreased quality of life. Our previous studies have shown that N. incisum root extract (NRE) can improve cognitive dysfunction in Alzheimer's disease (AD) mice. In addition, our research shows that AD and epilepsy have pathological mechanisms overlapping. Therefore, we tried to investigate whether NRE can ameliorate the seizures of epileptic mice in this study. NRE-treated mice group was given an oral administration with 1 g/kg/d for 7 days. On the 8th day, mice were exposed to PTZ (i.p. injection) to induce epilepsy. Then the cognitive tests of mice in the water maze were carried out, and the biochemical indexes and pathological tests were carried out after the mice were sacrificed. SOD level in the NRE group was significantly higher than that in the PTZ group, while MDA, TNF-α, and IL-1β levels were decreased. The cognitive ability of NRE-treated mice was significantly improved compared with the PTZ group. Immunohistochemistry (IHC) results showed that the activation of microglia and astrocytes in the hippocampus and cortex of NRE mice were inhibited. This study suggests that NRE can alleviate epilepsy and improve cognitive function in mice with epilepsy, and its mechanism may be through reducing inflammation and enhancing antioxidant defense.

MULMINATM REVERSES MEMORY IMPAIRMENT INDUCED BY GABAPENTIN IN PTZ EPILEPTIC MOUSE MODEL AND EXHIBITS SYNERGISTIC ANTIEPILEPTIC ACTIVITY

Epilepsy is a neurological condition that causes unprovoked, recurrent seizures and memory impairment is a common side effect of epileptic treatment. The present study was conceptualized to evaluate the protective effect of the nootropic herbal drink MulminaTM against memory impairment induced by Gabapentin in a pentylenetetrazole-induced epileptic mouse model. The antiepileptic and memory impairment activity were found to be significantly (p<0.05) higher in the gabapentin group, whereas the combination of gabapentin + MulminaTM significantly (p<0.05) increased antiepileptic and decreased the memory impairment activity. Furthermore, Mulmina, alone exhibited synergistic antiepileptic and memory enhancement activity. Thus, combining herbal drugs/nootropics with anti-epileptic drugs provides synergistic activity while lowering the dose of synthetic drugs, which may cause more adverse effects in the human body. The results of this study show that gabapentin has memory impairment potential and that it can be corrected by co-administration of MulminaTM. However, future research is warranted to assess the underlying molecular mechanism of memory enhancing activity of MulminaTM against gabapentin induced memory impairment.

Effect of A. graveolens hydroalcoholic extract on epilepsy-related damaging of Sox2 gene expression in embryos of epileptic mothers

BackgroundAnethum graveolens is a plant species belonging to the Apiaceae family that is commonly found in southwestern Asia (Iran-Khorasan province) and southeastern Europe. Previous studies have shown that A. graveolens extract may have anticonvulsant properties, reducing the frequency or severity of seizures in people with epilepsy. To better understand the mechanism behind how A. graveolens extract improves epilepsy, this study investigated the effects of the hydroalcoholic extract of A. graveolens leaves on the expression of the sox2 gene in the embryos of pregnant, epileptic mice. Sox2 is a transcription factor that plays a crucial role in the development of the nervous system, and its dysregulation has been implicated in various neurological disorders, including epilepsy. By examining the effects of A. graveolens extract on the expression of sox2 in embryonic epileptic mice, this study aimed to provide insights into the potential therapeutic benefits of this natural remedy for epilepsy. MethodsSixty BALB/c mice aged 6–8 weeks and weighing 25–30 g were used for this experiment. Four groups of 12 mice each were randomly selected from fully kindled pregnant mice. A. graveolens extract was administered intraperitoneally for 13 days to three experimental groups at doses of 100, 200, and 400 mg/kg/day, while the control group was given PBS. Following the final injection and completion of the protocol, mice were anesthetized with ether, and the heads of pregnant mice were cut to dissect prenatal mouse brains. Tissues were cut and immediately placed in RNA Later (QIAGEN) solution under sterile conditions for RNA extraction and analysis of sox2 gene expression. ResultsThe expression of the SOX2 gene was significantly reduced in the embryos of pregnant, epileptic mice compared to healthy controls and PBS group (P < 0.05) and (P < 0.0001), respectively. Additionally, intraperitoneal injections of 100 mg/kg/day of A. graveolens for 13 days significantly increased the expression of the sox2 gene in the embryos of pregnant epileptic mice. A similar effect was observed with 200 and 400 mg/kg/day of the extract, but it was less pronounced. Therefore, 100 mg/kg/day of A. graveolens may be optimal for exerting its protective effect on the brain expression of sox2 in embryonic epileptic mice. ConclusionsBased on the findings of this study, A. graveolens hydroalcoholic extract inhibits epilepsy-related damaging effects on Sox2 gene expression in the embryos of epileptic mothers.

Lipid-accumulated reactive astrocytes promote disease progression in epilepsy.

Reactive astrocytes play an important role in neurological diseases, but their molecular and functional phenotypes in epilepsy are unclear. Here, we show that in patients with temporal lobe epilepsy (TLE) and mouse models of epilepsy, excessive lipid accumulation in astrocytes leads to the formation of lipid-accumulated reactive astrocytes (LARAs), a new reactive astrocyte subtype characterized by elevated APOE expression. Genetic knockout of APOE inhibited LARA formation and seizure activities in epileptic mice. Single-nucleus RNA sequencing in TLE patients confirmed the existence of a LARA subpopulation with a distinct molecular signature. Functional studies in epilepsy mouse models and human brain slices showed that LARAs promote neuronal hyperactivity and disease progression. Targeting LARAs by intervention with lipid transport and metabolism could thus provide new therapeutic options for drug-resistant TLE.

The Potential Mechanism of Cannabidiol (CBD) Treatment of Epilepsy in Pentetrazol (PTZ) Kindling Mice Uncovered by Multi-Omics Analysis

Cannabidiol (CBD) is the main active ingredient in the cannabis plant used for treating epilepsy and related diseases. However, how CBD ameliorates epilepsy and its effect on the hippocampus remains unknown. Herein, we evaluated how CBD ameliorates seizure degree in pentylenetetrazol (PTZ) induced epilepsy mice after being exposed to CBD (10 mg/kg p.o). In addition, transcriptome and metabolomic analysis were performed on the hippocampus. Our results suggested that CBD could alleviate PTZ-induced seizure, of which the NPTX2, Gprc5c, Lipg, and Stc2 genes were significantly down-regulated in mice after being exposed to PTZ. Transcriptome analysis showed 97 differently expressed genes (CBD) and the PTZ groups. Metabonomic analysis revealed that compared with the PTZ group, 41 up-regulated and 67 down-regulated metabolites were identified in the hippocampus of epileptic mice exposed to CBD. The correlation analysis for transcriptome and metabolome showed that (±) 15-HETE and carnitine C6:0 were at the core of the network and were involved in the positive or negative regulation of the related genes after being treated with CBD. In conclusion, CBD ameliorates epilepsy by acting on the metabolism, calcium signaling pathway, and tuberculosis pathways in the hippocampus. Our study provided a practical basis for the therapeutic potential of treating epilepsy using CBD.

Activation of medial septum cholinergic neurons restores cognitive function in temporal lobe epilepsy.

Cognitive impairment is the most common complication in patients with temporal lobe epilepsy with hippocampal sclerosis. There is no effective treatment for cognitive impairment. Medial septum cholinergic neurons have been reported to be a potential target for controlling epileptic seizures in temporal lobe epilepsy. However, their role in the cognitive impairment of temporal lobe epilepsy remains unclear. In this study, we found that patients with temporal lobe epilepsy with hippocampal sclerosis had a low memory quotient and severe impairment in verbal memory, but had no impairment in nonverbal memory. The cognitive impairment was slightly correlated with reduced medial septum volume and medial septum-hippocampus tracts measured by diffusion tensor imaging. In a mouse model of chronic temporal lobe epilepsy induced by kainic acid, the number of medial septum cholinergic neurons was reduced and acetylcholine release was reduced in the hippocampus. Furthermore, selective apoptosis of medial septum cholinergic neurons mimicked the cognitive deficits in epileptic mice, and activation of medial septum cholinergic neurons enhanced hippocampal acetylcholine release and restored cognitive function in both kainic acid- and kindling-induced epilepsy models. These results suggest that activation of medial septum cholinergic neurons reduces cognitive deficits in temporal lobe epilepsy by increasing acetylcholine release via projections to the hippocampus.

Xanthohumol Alleviates Epileptic Seizures in Pentylenetetrazol-Induced Convulsions in Mice by Regulating Inflammation and Oxidative Stress

Background: Epilepsy is a prevalent neurobehavioral disorder, which affects more the 50 million individuals worldwide. It is characterized by neuron hyperexcitability mediated by repetitive convulsions. The current investigation was planned to study the therapeutic properties of the xanthohumol against pentylenetetrazol (PTZ)-induced convulsions in mice by regulating inflammation and oxidative stress. Methods: The 70 mg/kg of PTZ was administered (i.p.) to the mice for stimulating the epileptic seizures and 20 mg/kg of xanthohumol was pre-treated by oral route before the 30 min of PTZ administration. The mice were observed closely for 30 min after the PTZ treatment to detect the onset and duration of clonic/tonic convulsions and mortality. The status of glutamate, GABA, dopamine, Na+K+ATPase, and Ca+ATPase were quantified using respective kits. The level of MDA, NO, GSH, and SOD were detected using standard methods. The levels of inflammatory biomarkers such as COX-2, TNF-α, NF-κB, TLR-4, and IL-1β in the brain tissues were inspected using kits. The histopathological analysis was done on the brain tissues. Results: The xanthohumol significantly (p &lt; 0.05) reduced the onset and duration of convulsions, mortality, and behavioral changes in the epileptic mice. The levels of COX-2, TNF-α, NF-κB, TLR-4, and IL-1β were significantly (p &lt; 0.05) decreased in the epileptic mice by 20 mg/kg xanthohumol treatment. The levels of MDA and NO was reduced and GSH and SOD were increased by the 20 mg/kg xanthohumol treatment. The 20 mg/kg xanthohumol significantly (p &lt; 0.05) decreased the glutamate and improved the dopamine, GABA, Na+K+ATPase, and Ca+ATPase in the epileptic mice. The findings of histopathological studies revealed that 20 mg/kg xanthohumol decreased the inflammatory signs and pyknosis in the brain tissues. Conclusion: Pre-treatment with the 20 mg/kg xanthohumol ameliorates the PTZ-triggered seizures in a mice model through its antioxidant and anti-inflammatory potentials. Hence, xanthohumol can be a promising antiepileptic candidate in the future to treat epilepsy.

Superoxide anion monitoring in epileptic brains with a near-infrared fluorescent probe

Epilepsy is a chronic neurological disorder, and the pathophysiological progression to status epilepticus is closely associated with oxidative stress. Superoxide anions (O2•-), as the main, most important precursor of other reactive oxygen species (ROS), play a crucial role in seizure-induced brain damage. However, detecting the actual O2•- levels and understanding the physiological roles of O2• in epileptic brains remain challenging due to the lack of effective in vivo detection tools. Herein, a new near-infrared fluorescent probe, MB-SO, was prepared for the determination of endogenous O2•- in brains experiencing pentylenetetrazole (PTZ)-induced epileptic seizures. MB-SO exhibits high sensitivity (detection limit of 14 nM), good selectivity and a fast response towards O2•-. MB-SO was applied in situ to monitor endogenous O2•- in living HT-22 cells and living mice. Using this probe, we visualized and quantitatively detected endogenous O2•- for the first time in the hippocampi of PTZ-induced epileptic mouse brains. MB-SO also displayed a positive correlation between high O2•- levels in epileptic brains and epileptogenesis. These results indicated that the probe MB-SO is an efficient tool for monitoring endogenous O2•- in vivo and exploring the pathogenesis of epilepsy.

Structural Analogs of the GABAkine KRM-II-81 Are Orally Bioavailable Anticonvulsants without Sedation.

To provide back-up compounds to support the development of the GABAA receptor (GABAAR) potentiator KRM-II-81, three novel analogs were designed: replacing the pyridinyl with 2'-Cl-phenyl (FR-II-60), changing the positions of the N and O atoms in the oxazole ring with addition of an ethyl group (KPP-III-34 and KPP-III-51), or substituting a Br atom for the ethynyl of KRM-II-81 (KPP-III-34). The compounds bound to brain GABAARs. Intraperitoneal administration of FR-II-60 and KPP-III-34 produced anticonvulsant activity in mice [maximal electroshock (MES)-induced seizures or 6 Hz-induced seizures], whereas KPP-III-51 did not. Although all compounds were orally bioavailable, structural changes reduced the plasma and brain (FR-II-60 and KPP-III-51) exposures relative to KRM-II-81. Oral administration of each compound produced dose-dependent increases in the latency for both clonic and tonic seizures and the lethality induced by pentylenetetrazol (PTZ) in mice. Since KPP-III-34 produced the highest brain area under the curve (AUC) exposures, it was selected for further profiling. Oral administration of KPP-III-34 suppressed seizures in corneal-kindled mice, hippocampal paroxysmal discharges in mesial temporal lobe epileptic mice, and PTZ-induced convulsions in rats. Only transient sensorimotor impairment was observed in mice, and doses of KPP-III-34 up to 500 mg/kg did not produce impairment in rats. Molecular docking studies demonstrated that all compounds displayed a reduced propensity for binding to α1His102 compared with the sedating compound alprazolam; the bromine-substituted KPP-III-34 achieved the least interaction. Overall, these findings document the oral bioavailability and anticonvulsant efficacy of three novel analogs of KRM-II-81 with reduced sedative effects. SIGNIFICANCE STATEMENT: A new non-sedating compound, KRM-II-81, with reduced propensity for tolerance is moving into clinical development. Three new analogs were orally bioavailable, produced anticonvulsant effects in rodents, and displayed low sensorimotor impairment. KPP-III-34 demonstrated efficacy in models of pharmacoresistant epilepsy. Docking studies demonstrated a low propensity for compound binding to the α1His102 residue implicated in sedation. Thus, three additional structures have been added to the list of non-sedating imidazodiazepine anticonvulsants that could serve as backups in the clinical development of KRM-II-81.

Rutin-loaded selenium nanoparticles modulated the redox status, inflammatory, and apoptotic pathways associated with pentylenetetrazole-induced epilepsy in mice

Abstract Worldwide, epilepsy is the second most prevalent neurological disorder. Disappointingly, various adverse effects are being observed with currently used antiepileptic drugs. Nanomedicine represents an effective strategy to overcome these limitations with a better central drug delivery. Hence, our work aimed to unravel the antiepileptic efficacy of rutin (Rut) loaded with selenium nanoparticles (SeNPs) against pentylenetetrazole (PTZ)-challenged mice. Ten days before PTZ (60 mg·kg−1) intraperitoneal injection, mice were orally administered Rut (100 mg·kg−1), sodium selenite (0.5 mg·kg−1), SeNPs (100 mg·kg−1), or sodium valproate (reference drug, 200 mg·kg−1). Remarkably, administration of Rut-loaded SeNPs (Rut-SeNPs) to epileptic mice markedly increased the latency time and decreased the severity and duration of seizures. Remarkable increases were also noticed in acetylcholinesterase, brain-derived neurotrophic factor, dopamine, and norepinephrine levels in epileptic mice treated with Rut-SeNPs. Furthermore, Rut-SeNPs boosted the cellular antioxidant defense by increasing superoxide dismutase, catalase, GSH, Nrf2, and HO-1, along with decreased malondialdehyde and nitric oxide levels. In addition, the nanotherapy successfully mitigated the inflammatory mediators (tumor necrosis factor-α, interleukin-6, cyclooxygenase-2, and nuclear factor kappa B) in mice hippocampus. Rut-SeNPs antagonized neuronal apoptosis by decreasing Bax and caspase-3 and increasing the levels of Bcl-2. Conclusively, the present work suggests Rut-loaded SeNPs as an effective antiepileptic therapy through correction of disturbed neurotransmitters, oxidative status, neuroinflammation, and apoptosis.

Fast-Specific Fluorescent Probes to Visualize Norepinephrine Signaling Pathways and Its Flux in the Epileptic Mice Brain.

Norepinephrine (NE) is synthesized in the locus coeruleus and widely projected throughout the brain and spinal cord. It regulates various actions and consciousness linked to a variety of neurological diseases. A "hunting-shooting" strategy was proposed in this work to improve the specificity and response rate of an NE fluorescent probe: 2-(cyclohex-2-en-1-ylidene)malononitrile derivatives were chosen as a fluorophore. To create a dual-site probe, an aldehyde group was added to the ortho of the ester group (or benzene sulfonate). Because of its excellent electrophilic activity, the aldehyde group could rapidly "hunt" the amino group and then form an intramolecular five-membered ring via the nucleophilic reaction with the β-hydroxyl group. The -NH- in the five-membered ring "shoots" the adjacent ester group, releasing the fluorophore and allowing for rapid and specific NE detection. The NE release and reuptake ″emetic″-″swallow″ transient process is captured and visualized under the action of the primary NE receptor drug. Furthermore, by introducing halogen into the fluorophore to lengthen the absorption wavelength, improve lipid solubility, and adjust the pKa appropriately, the probe successfully penetrated the blood-brain barrier (BBB). In situ synchronous probe imaging was used to detect the NE level in the brains of epileptic and normal mice, and abnormal expression of NE in the brain was discovered during epilepsy. Brain anatomy was used to examine the distribution and level changes of NE in various brain regions before and after epilepsy. This research provides useful tools and a theoretical foundation for diagnosing and treating central nervous system diseases early.

Developmental Inhibitory Changes in the Primary Somatosensory Cortex of the Stargazer Mouse Model of Absence Epilepsy.

Childhood absence epilepsy seizures arise in the cortico-thalamocortical network due to multiple cellular and molecular mechanisms, which are still under investigation. Understanding the precise mechanisms is imperative given that treatment fails in ~30% of patients while adverse neurological sequelae remain common. Impaired GABAergic neurotransmission is commonly reported in research models investigating these mechanisms. Recently, we reported a region-specific reduction in the whole-tissue and synaptic GABAA receptor (GABAAR) α1 subunit and an increase in whole-tissue GAD65 in the primary somatosensory cortex (SoCx) of the adult epileptic stargazer mouse compared with its non-epileptic (NE) littermate. The current study investigated whether these changes occurred prior to the onset of seizures on postnatal days (PN) 17-18, suggesting a causative role. Synaptic and cytosolic fractions were biochemically isolated from primary SoCx lysates followed by semiquantitative Western blot analyses for GABAAR α1 and GAD65. We found no significant changes in synaptic GABAAR α1 and cytosolic GAD65 in the primary SoCx of the stargazer mice at the critical developmental stages of PN 7-9, 13-15, and 17-18. This indicates that altered levels of GABAAR α1 and GAD65 in adult mice do not directly contribute to the initial onset of absence seizures but are a later consequence of seizure activity.

Progesterone receptor membrane component 2 regulates the neuronal activity and participates in epileptic seizures in experimental mice.

It was found the expression of progesterone receptor membrane component 2 (PGRMC2) in the histone of epileptic mice was lower than that of normal mice. In this study, we found by the immunofluorescence technique, PGRMC2 was expressed in both astrocytes and neurons of the mouse hippocampus. In addition, the seizure latency and seizure grade of mice in each group were observed after stereotactic injection of the PGRMC2 knockdown virus, PGRMC2 overexpression lentivirus, and related null virus into the hippocampus of mice. It was found that the seizure latency of mice in the PTZ + siPGRMC2 group was prolonged compared with the null virus group. The seizure latency was shortened in the PTZ + PGRMC2 group. The number of grade IV and above seizures in the PTZ + siPGRMC2 group was significantly reduced, while the number of grade IV and above seizures in the PTZ + PGRMC2 group was significantly increased. It was found that the nerve cells in the PTZ + siPGRMC2 group were still intact. In the PTZ + PGRMC2 group, the neural cells were damaged, the intercellular space was widened, and the number of cells was reduced. These findings support that PGRMC2 may be involved in epileptic seizures.

Neurotoxic A1 astrocytes promote neuronal ferroptosis via CXCL10/CXCR3 axis in epilepsy

Epilepsy is a common neurological disorder with a complex etiology. Ferroptosis, a new form of programmed cell death, is characterized by the accumulation of lipid peroxides and associated with seizures. However, the underlying mechanism of ferroptosis in epilepsy remains elusive. Here, we found that GPX4-GSH-dependent neuronal ferroptosis was detected in epileptic mice, which was attenuated with ferroptosis inhibitors. Moreover, activated neurotoxic A1 astrocytes facilitated seizure-related neuronal ferroptosis in epileptic brains. Inhibition of ferroptosis blocked A1 astrocyte-induced neurotoxicity. A1 astrocyte-secreted CXCL10 enhanced STAT3 phosphorylation but suppressed SLC7A11 in neurons via CXCR3, leading to ferroptosis-associated lipid peroxidation in a GPX4-dependent manner. This was in line with clinical findings, showing a significant correlation between neuronal ferroptosis and A1 astrocytes in epileptic patients. In summary, the present data show that A1 astrocyte-induced neuronal ferroptosis contributes to the pathogenesis of epilepsy, which offers a novel therapeutic target for precision medicine.