El Mice Research Articles

Melatonin Improves Glucose Homeostasis and Insulin Sensitivity by Mitigating Inflammation and Activating AMPK Signaling in a Mouse Model of Sleep Fragmentation.

Sleep fragmentation (SF) can increase inflammation and production of reactive oxygen species (ROS), leading to metabolic dysfunction. SF is associated with inflammation of adipose tissue and insulin resistance. Several studies have suggested that melatonin may have beneficial metabolic effects due to activating AMP-activated protein kinase (AMPK). However, it is unclear whether melatonin affects the AMPK signaling pathway in SF-induced metabolic dysfunction. Therefore, we hypothesize that SF induces metabolic impairment and inflammation in white adipose tissue (WAT), as well as altered intracellular homeostasis. We further hypothesize that these conditions could be improved by melatonin treatment. We conducted an experiment using adult male C57BL/6 mice, which were divided into three groups: control, SF, and SF with melatonin treatment (SF+Mel). The SF mice were housed in SF chambers, while the SF+Mel mice received daily oral melatonin. After 12 weeks, glucose tolerance tests, insulin tolerance tests, adipose tissue inflammation tests, and AMPK assessments were performed. The SF mice showed increased weight gain, impaired glucose regulation, inflammation, and decreased AMPK in WAT compared to the controls. Melatonin significantly improved these outcomes by mitigating SF-induced metabolic dysfunction, inflammation, and AMPK downregulation in adipose tissue. The therapeutic efficacy of melatonin against cardiometabolic impairments in SF may be due to its ability to restore adipose tissue homeostatic pathways.

ELMO CPAP: an innovative type of ventilatory support for COVID-19-related acute respiratory distress syndrome.

To assess whether the use of ELMO, a helmet for noninvasive ventilation created in Brazil, had a positive impact on the prognosis of patients with hypoxemic respiratory failure caused by severe COVID-19. This is a retrospective study of 50 critically ill COVID-19 patients. Epidemiological, clinical, and laboratory data were collected on ICU admission, as well as before, during, and after ELMO use. Patients were divided into two groups (success and failure) according to the outcome. ELMO use improved oxygenation parameters such as Pao2, Fio2, and the Pao2/Fio2 ratio, and this contributed to a gradual reduction in Fio2, without an increase in CO2, as determined by arterial blood gas analysis. Patients in the success group had significantly longer survival (p < 0.001), as determined by the Kaplan-Meier analysis, less need for intubation (p < 0.001), fewer days of hospitalization, and a lower incidence of acute kidney injury in comparison with those in the failure group. The significant improvement in oxygenation parameters, the longer survival, as reflected by the reduced need for intubation and by the mortality rate, and the absence of acute kidney injury suggest that the ELMO CPAP system is a promising tool for treating ARDS and similar clinical conditions.

Commonality between EL mice and patients of ADHD on EEG power spectrum and θ/β ratio.

Commonality between EL mice and patients of ADHD on EEG power spectrum and θ/β ratio.

The Roles of Dominance of the Nitric Oxide Fractions Nitrate and Nitrite in the Epilepsy-Prone EL Mouse Brain.

Oxidative stress is thought to be closely related to epileptogenesis. We have previously reported that nitric oxide (NO) levels are higher in epilepsy-prone EL mice between the ages of 3 and 8 weeks than in control mice. However, NO is divided into two fractions, nitrite (NO2) and nitrate (NO3), which appear to play different roles in epileptogenesis. NO2 and NO3 levels were measured, in EL mice and the control mice, in the parietal cortex, which is thought to be the primary epileptogenetic center in EL mice, and measured in the hippocampus, which is thought to be the secondary center. NO3 levels in the hippocampus and parietal cortex of the immature EL mice (3 to 8 weeks of age) were significantly higher than those in the control mice; NO2 levels were significantly higher in the EL mice throughout the study period. The NO3 levels were significantly higher than the NO2 levels in the immature EL mice, but after the onset of ictogenesis at 10 weeks of age, the relative levels of the two fractions reversed. The reversal of the NO fraction distribution at the onset of seizures that we observed may be related to the developmental process of seizure susceptibility in the neural network of EL mice.

Environmental enrichment alleviates cognitive and behavioral impairments in EL mice

Epilepsy in children is occasionally associated with comorbidities, such as cognitive impairment, behavioral disturbances, and social deficits. These neurobehavioral comorbidities are closely related to environmental factors and the severity of the seizures. Previous studies show that environmental enrichment has a beneficial effect in animal models of temporal lobe epilepsy following systemic chemoconvulsant administration. However, the effect of environmental enrichment on behavioral impairments in the EL mouse, a genetic model of human idiopathic epilepsy, remains unknown. In the present study, we examined the effect of environmental enrichment on cognitive and behavioral impairments in this murine model. The EL mice, under standard laboratory conditions, exhibited impairments in spatial memory in the Morris water maze test, hyperactivity and impaired habituation in the open-field test, and a deficit in social novelty preference in the three-chamber social approach test, compared with control DDY mice, a genetically related nonepileptic strain. These impairments in EL mice were ameliorated by exposure to an enriched environment. These findings suggest that environmental enrichment effectively ameliorates cognitive and behavioral deficits in EL mice.

現在までのELマウス研究

現在までのELマウス研究

Anticancer agent 6-MITC at extremely low dosage can control seizures by stabilizing membrane excitability system in mutant EL mice

Anticancer agent 6-MITC at extremely low dosage can control seizures by stabilizing membrane excitability system in mutant EL mice

Abnormal Plasticity and Epigenesis in Epileptic Seizures of an EL Mouse

Abnormal Plasticity and Epigenesis in Epileptic Seizures of an EL Mouse

Ketogenic diets improve behaviors associated with autism spectrum disorder in a sex-specific manner in the EL mouse

The core symptoms of autism spectrum disorder are poorly treated with current medications. Symptoms of autism spectrum disorder are frequently comorbid with a diagnosis of epilepsy and vice versa. Medically-supervised ketogenic diets are remarkably effective nonpharmacological treatments for epilepsy, even in drug-refractory cases. There is accumulating evidence that supports the efficacy of ketogenic diets in treating the core symptoms of autism spectrum disorders in animal models as well as limited reports of benefits in patients. This study tests the behavioral effects of ketogenic diet feeding in the EL mouse, a model with behavioral characteristics of autism spectrum disorder and comorbid epilepsy. Male and female EL mice were fed control diet or one of two ketogenic diet formulas ad libitum starting at 5weeks of age. Beginning at 8weeks of age, diet protocols continued and performance of each group on tests of sociability and repetitive behavior was assessed. A ketogenic diet improved behavioral characteristics of autism spectrum disorder in a sex- and test-specific manner; ketogenic diet never worsened relevant behaviors. Ketogenic diet feeding improved multiple measures of sociability and reduced repetitive behavior in female mice, with limited effects in males. Additional experiments in female mice showed that a less strict, more clinically-relevant diet formula was equally effective in improving sociability and reducing repetitive behavior. Taken together these results add to the growing number of studies suggesting that ketogenic and related diets may provide significant relief from the core symptoms of autism spectrum disorder, and suggest that in some cases there may be increased efficacy in females.

Development of a Seizure and Epileptogenesis in EL Mouse

Development of a Seizure and Epileptogenesis in EL Mouse

Fgf20 and Fgf4 may contribute to tooth agenesis in epilepsy-like disorder mice

Background/purposeTooth agenesis is one of the most clearly recognized dental anomalies in the permanent dentition and can be challenging to manage clinically. Recent genetic studies identified several genes related to syndromic and nonsyndromic human dental agenesis. However, the genetic factors related to agenesis of the third molars (M3s), second premolars, and lateral incisors, which are most commonly involved in hypodontia, are still unknown. Therefore, this study aimed to identify the genetic causes of the lacking M3s in epilepsy-like disorder (EL) mice, which have 100% incidence of M3 agenesis. MethodsM3 tooth germs from EL and C57BL/6 control mice on postnatal day 3 were dissected out and total RNA was extracted. mRNA expressional analysis was carried out using DNA microarray, real-time polymerase chain reaction and in-situ hybridization. ResultsDNA microarray analysis revealed significantly decreased expression of Fgf20 and Fgf4 and increased expression of EDA in the M3s of EL mice at the bud stage relative to C57BL/6 control mice, which was supported with both reverse-transcriptase polymerase chain reaction and real-time polymerase chain reaction analyses (p < 0.05). Furthermore, in-situ hybridization revealed low mRNA expression levels of Fgf20 and Fgf4 in the M3s of EL mice, whereas strong signals were observed in control mice. ConclusionOur results suggest that a decrease of Fgf20 and Fgf4 expression may lead to M3 agenesis in EL mice. Understanding the mechanisms controlling tooth agenesis will facilitate the development of strategies for tooth bioengineering.

Effects of Edaravone on Hippocampal Antioxidants in EL Mice.

The role of oxidative stress in susceptibility to seizures has been the focus of several recent studies. The aim of the present study was to evaluate the antiepileptic effects of the free radical scavenger edaravone on EL mice, a strain that is highly susceptible to convulsive seizures. EL mice were treated intraperitoneally with edaravone or saline for 1 week. The levels of reduced glutathione (GSH), oxidized glutathione (GSSG) and 3 isozymes of superoxide dismutase (SOD) (cytoplasmic copper- and zinc-containing SOD, extracellular SOD, and mitochondrial manganese-containing SOD) were measured in the hippocampus, and electroencephalograms (EEGs) were used to evaluate seizure sensitivity. Hippocampal levels of GSSG were lower in the edaravone group than in the untreated control group, and the GSH/GSSG ratio, Cu/Zn-SOD, and EC-SOD activities were higher in the edaravone group. Edaravone shortened the duration of interictal spike discharges and clinically suppressed epileptic seizures. Edaravone increases antioxidant potency and reduces seizure susceptibility in EL mice, making it a promising novel antiepileptic agent.

Significance of Glutathione-Mediated Scavenger Potency in the Development of Seizure Susceptibility in the EL Mouse Brain

It has been reported that oxidative stress is closely related to the development of seizure susceptibility. To investigate if the redox condition shifts to an oxidized state during ictogenesis in epilepsy-prone EL mice, which shows the first seizure episode at 8 to 10 weeks of age, changes in the activities in the hippocampus or parietal cortex of reduced glutathione (GSH), oxidized glutathione, glutathione peroxidase, and nitric oxide were examined. This study showed that GSH activities were lower and oxidized glutathione activities were higher in EL mice than in ddY mice, mother strain control of EL, even though glutathione peroxidase activities were higher in EL mice between the ages of 3 and 8 weeks. Similarly, nitric oxide activities were higher in EL mice. The study also showed that GSH-mediated scavenger potency was lower not only in the hippocampus but also in the parietal cortex of EL mice at an early age. This reduction in GSH-mediated scavenger potency may be related to the acquisition of epileptogenesis in both the primary (parietal cortex) and secondary (hippocampus) epileptogenic centers of EL mice.

Reduced glucose utilization underlies seizure protection with dietary therapy in epileptic EL mice

Dietary therapy has been used to treat many individuals with epilepsy whose seizures are refractory to antiepileptic drugs. The mechanisms for how dietary therapy confers seizure protection are currently not well understood. We evaluated the acute effects of glucose and β-hydroxybutyrate (the major circulating ketone body) in conferring seizure protection to the EL mouse, a model of multifactorial idiopathic generalized epilepsy. EL mice were fed either an unrestricted standard diet or a calorie-restricted standard diet to achieve a body weight reduction of 20–23%. d-Glucose, 2-deoxy-d-glucose, and β-hydroxybutyrate were supplemented in the drinking water of calorie-restricted mice for 2.5h prior to seizure testing to simulate the effect of increased glucose availability, decreased glucose utilization, and increased ketone availability, respectively. Seizure susceptibility, body weight, plasma glucose, and β-hydroxybutyrate were measured over a nine-week treatment period. Additionally, excitatory and inhibitory amino acids were measured in the brains of mice using 1H NMR. Glutamate decarboxylase activity was also measured to evaluate the connection between dietary therapy and brain metabolism. We found that lowering of glucose utilization is necessary to confer seizure protection with long-term (>4weeks) calorie restriction, whereas increased ketone availability did not affect seizure susceptibility. In the absence of long-term calorie restriction, however, reduced glucose utilization and increased ketone availability did not affect seizure susceptibility. Brain excitatory and inhibitory amino acid content did not change with treatment, and glutamate decarboxylase activity was not associated with seizure susceptibility. We demonstrated that reduced glucose utilization is necessary to confer seizure protection under long-term calorie restriction in EL mice, while acute ketone supplementation did not confer seizure protection. Further studies are needed to uncover the mechanisms by which glucose utilization influences seizure susceptibility.

Glucose reduces the anticonvulsant effects of the ketogenic diet in EL mice

The ketogenic diet (KD) is known to be anticonvulsant and anti-epileptogenic. While the mechanism behind this therapeutic benefit is unclear, a reduction of circulating glucose levels through calorie restriction (CR) has been implicated. Foods or drinks that elevate blood glucose are known to compromise the therapeutic benefit of the KD in some children with epilepsy. We therefore evaluated the effect of a calorie restricted KD (KD-R) with supplementation of glucose in the drinking water of EL mice, a natural model of idiopathic generalized epilepsy, prior to seizure testing to assess the effect of glucose on seizure generation. Mice were fed either a standard diet or the KD unrestricted (SD-UR and KD-UR, respectively), or the KD restricted (KD-R). d-Glucose (25 mM) was supplemented in the drinking water of KD-R fed mice for 0.5h or for 2.5h prior to seizure testing. Each restricted mouse served as its own body weight control to achieve a 15-18% body weight reduction. Seizure susceptibility, body weights, and plasma glucose and β-hydroxybutyrate levels were measured over a nine-week treatment period. Body weights and glucose levels remained high over the testing period in both the SD-UR and the KD-UR groups, but were significantly reduced in all R-fed groups. A significant increase in β-hydroxybutyrate levels was observed in all KD groups. Seizure susceptibility remained highest in the SD-UR group, was slightly reduced in the KD-UR group, and was significantly reduced after three weeks in all R-fed groups. Supplementation of glucose prior to seizure testing resulted in a decrease of seizure threshold for R-fed mice, but did not alter bodyweight or circulating glucose levels. The KD has both an anticonvulsant and antiepileptogenic effect in EL mice. Here we confirm that CR enhances the anticonvulsant action of the KD in EL mice. Additionally, we show for the first time that supplementation of glucose decreases the anticonvulsant action of the KD, which further supports the hypothesis that CR works through transitioning metabolism from glucose to ketone utilization for energy.

Electroencephalographic features of familial spontaneous epileptic cats

A feline strain of familial spontaneous epileptic cats (FSECs) with typical limbic seizures was identified in 2010, and have been maintained as a novel animal model of genetic epilepsy. In this study, we characterized the electroencephalographic (EEG) features of FSECs. On scalp EEG under sedation, FSECs showed sporadic, but comparatively frequent interictal discharges dominantly in the uni- or bilateral temporal region. Bemegride activation was performed in order to evaluate the predisposition of epileptogenicity of FSECs. The threshold doses of the first paroxysmal discharge, clinical myoclonus and generalized convulsion in FSECs were significantly lower than those in control cats. Chronic video-intracranial EEG monitoring revealed subclinical or clinical focal seizures with secondarily generalization onset from the unilateral amygdala and/or hippocampus. Clinical generalized seizures were also recorded, but we were unable to detect the onset site. The results of the present study show that FSECs resemble not only feline kindling or the kainic acid model and El mouse, but also human familial or sporadic mesial temporal lobe epilepsy. In addition, our results indicate that FSECs are a natural and valuable model of mesial temporal lobe epilepsy.

&amp;lt;i&amp;gt;Lef&amp;lt;/i&amp;gt;1 may contribute to agenesis of the third molars in mice

Tooth agenesis is the most common developmental anomaly of the human dentition. Epilepsy-like disorder (EL) mice, which have a 100% incidence of agenesis of the third molars, may be a good model for the genetic study of human tooth agenesis. Our previous congenic breeding strategy using EL mice confined a major locus for agenesis of M3, designated am3, within an approximately 1 Mega base pair (Mbp) interval on chromosome 3, which contains five known genes; Lef1, Hadh, Cyp2u1, Sgms2 and Papss1. The aim of this study was to identify the strongest candidate for am3 among the five genes using real-time PCR analysis. The tooth germs of M3 in the bud stage of EL and control mice were dissected out, and total RNA was extracted. In real-time PCR analysis, a significantly low level of expression of Lef1, which is one of the essential transcription factors for early tooth development, was observed in M3 of EL mice. In addition, a significantly low level of expression of Fgf4, which is a direct transcriptional target for LEF1 in early tooth development, was observed in M3 of EL mice. Our results suggest that the cause of M3 agenesis of EL mice may be a low level of Lef1 expression in M3 in the bud stage of EL mice.

Neuronal mechanism of epileptogenesis in EL mouse

The convulsions of the EL mouse (EL) were described by Imaizumi et al. in 1954 and were established as epilepsy by Suzuki in 1976. The EL mouse has been kept as an inbred strain and is considered one of the best animal models originated in Japan. The mode of inheritance is autosomal dominant, and environmental risk factors for seizure occurrence are hypothesised to contribute to the polygenic background. Paroxysmal activities in the EL brain arise from the parietal cortex (PCX) and are augmented in the hippocampus, demonstrated by electrophysiology and autoradiography using 2-deoxy glucose when clinical symptoms of seizures appeared. The neurons in the EL PCX, where GABA activity is lower than that of DDY PCX demonstrate increased excitability to proprioceptive sensory input. After repetitive seizure-provoking stimuli, seizures are more easily induced, eventually occurring spontaneously. This phenomenon of “abnormal plasticity” is also observed in the EEG, decreasing GABA activity, expression of the immediately early gene, and various biochemical and molecular processes. This phenomenon is similar to the learning or progressive process of certain neurological diseases.

Neuronal activity in the parietal cortex of EL and DDY mice

To elucidate the mechanism of epileptogenesis, seizures were investigated in the EL mouse, which is an excellent model for epilepsy. In these mice, epileptic seizures initiate in the parietal cortex, where markers of GABA-mediated inhibition are reduced compared with the parietal cortex of DDY mice (the parent strain). This is the first report on units of neuronal activity in the parietal cortex of EL and DDY mice (14 each) using an extracellular microelectrode in vivo under moderate pentobarbital anesthesia. The parietal cortex neurons of the EL mice were less active at rest than those of the DDY mice, but they responded more actively to proprioceptive afferent input from muscle stimulation than the DDY neurons. Three types of spontaneous firing were classified in both EL and DDY cortical neurons: periodically firing, Type A; continuously firing, Type B; and random firing, Type C. The proportions of these three types of neurons were almost the same in the EL mice as in the DDY mice. The peak frequency of the periodical cycle of Type A neurons in the EL mice (375 ms) was longer than that of the Type A neurons in the DDY mice (225 ms). Four patterns of responses to stimulation were observed in the parietal cortex neurons. More excitatory patterns were observed in the EL mice than in the DDY mice. The trans-laminar distribution of cells with different response patterns was also different between the EL and DDY mice. These characteristics of parietal cortex neurons may help determine the seizure susceptibility or ictogenesis in EL mice because the mechanisms underlying these patterns could provide the basis for hypersynchronized discharges in epileptic seizures.

Sub-chronic treatment with pioglitazone exerts anti-convulsant effects in pentylenetetrazole-induced seizures of mice: The role of nitric oxide

Pioglitazone delayed the development of seizure responses and shortened the duration of convulsion of genetically epileptic EL mice. The anti-epileptic effect of pioglitazone was attributed partly through the reduction of inflammatory responses and preventing apoptosis. There are also some reports showing that some pioglitazone effects mediate through nitric oxide. In this study we evaluated sub-chronic pioglitazone effects in two models of intravenous and intraperitoneal pentylenetetrazole-induced clonic seizures in mice. Different doses of pioglitazone were administered orally for 10 days in different groups of male mice. L-NAME, a non selective inhibitor of nitric oxide synthase, aminoguanidine, a selective inhibitor of inducible nitric oxide synthase, or L-arginine, a nitric oxide donor, was administered acutely or sub-chronically to evaluate the role of nitric oxide in pioglitazone anti-seizure effects. We demonstrated that sub-chronic administration of pioglitazone exerted anti-convulsant effects in both models of intravenous and intraperitoneal pentylenetetrazole. Acute and sub-chronic pre-administration of L-NAME prevented the anti-convulsant effect of pioglitazone in both models of intravenous and intraperitoneal pentylenetetrazole. Aminoguanidine did not alter the anti-convulsant effect of pioglitazone in two models of intravenous and intraperitoneal pentylenetetrazole. Both acute and sub-chronic pre-treatment of mice with L-arginine exerted anti-convulsant effect when administered with a non effective dose of pioglitazone in intraperitoneal method. In intravenous method, acute administration of L-arginine with a non-effective dose of pioglitazone enhanced the seizure clonic latency. Taken together, sub-chronic pioglitazone treatment exerts anti-convulsant effects in intravenous and intraperitoneal pentylenetetrazole-induced seizures of mice probably through induction of constitutive nitric oxide synthase.