Anticonvulsant action of a selective phosphatidylinositol-3-kinase inhibitor LY294002 in pentylenetetrazole-mediated convulsions in zebrafish

Phenylthiourea-mediated experimental depigmentation reduces seizurogenic response of pentylenetetrazol in zebrafish larva

Zebrafish larvae exposed to chemoconvulsants show behavioral seizures and electrographic abnormalities similar to the other mammalian models, making it a potential tool in epilepsy research. During the embryonic stage, zebrafish remains transparent which enables real-time developmental detection and in-situ gene/protein expression. However, pigmentation during the larval stage restricts transparency. Phenylthiourea (1-phenyl-2-thiourea; PTU) is a commonly used pigmentation blocker that maintains larval transparency. It is widely used along with chemoconvulsants to study in situ expressions in epileptic larvae, however, its effect on seizures largely remains unknown. Therefore, in the present study, the effect of PTU-mediated depigmentation was studied on pentylenetetrazol (PTZ)-induced seizures in zebrafish larvae. After spawning, the fish embryos were subjected to standard depigmentation protocol using 0.13 mM PTU. At 7-days post fertilization seizures were induced using 8 mM PTZ. PTU exposure significantly reduced PTZ-mediated hyperactive responses indicated by decreased distance travelled and swimming velocity of the larvae. Furthermore, PTU-exposed depigmented larvae also showed an increase in the latency to the onset of PTZ-mediated clonic-like seizures. The results concluded that PTU depigmentation protocol reduces the seizurogenic response of PTZ, hence its usage for imaging zebrafish larvae must be carefully monitored to avoid erroneous results.

The functional and molecular roles of p75 neurotrophin receptor (p75NTR) in epilepsy

Epilepsy is a chronic neurological disorder manifested by recurring unprovoked seizures resulting from an imbalance in the inhibitory and excitatory neurotransmitters in the brain. The process of epileptogenesis involves a complex interplay between the reduction of inhibitory gamma-aminobutyric acid (GABA) and the enhancement of excitatory glutamate. Pro-BDNF/p75NTR expression is augmented in both glial cells and neurons following epileptic seizures and status epileptics (SE). Over-expression of p75NTR is linked with the pathogenesis of epilepsy, and augmentation of pro-BDNF/p75NTR is implicated in the pathogenesis of epilepsy. However, the precise mechanistic function of p75NTR in epilepsy has not been completely elucidated. Therefore, this review aimed to revise the mechanistic pathway of p75NTR in epilepsy.

Fagopyrum tataricum (L.) Gaertn interacts with Gsk-3β/Nrf-2 signalling to protect neurotoxicity in a zebrafish model

ETHNOPHARMACOLOGICAL RELEVANCE

Fagopyrum tataricum (L.) Gaertn is used as a folk medicine in many Asian countries due to its anti-inflammatory, antioxidant, and several other health-promoting properties. It is also prescribed to improve neurocognitive functions and alleviate inflammatory conditions.

AIM OF THE STUDY

Oxidative stress and neuroinflammation plays a crucial role in neurodegenerative conditions. Hence, based on the ethnomedical claims and available literature, the present study investigated neuroprotective efficacy of a seed extract (ft-ext) of Fagopyrum tataricum against acrylamide (ACR)-induced neurotoxicity.

MATERIALS AND METHODS

The phytochemical characterization of ft-ext was performed by a high-performance liquid chromatography method. Molecular interactions of the identified compounds of ft-ext were studied using an in-silico docking tool. An in-vitro protein denaturation assay was done to check anti-inflammatory activity. The 5 days' post-fertilized zebrafish larvae were exposed to 1 mM and 2.5 mM ACR with or without ft-ext for 72 h to study its neuroprotective efficacy. Real-time polymerase chain reaction and western blotting studies were performed to analyse the oxidative stress-related gene and protein expressions respectively.

RESULTS

The extract showed the presence of chlorogenic acid, rutin, caffeic acid, vitexin, syringic acid, quercetin, p-coumaric acid, kaempferol, and ferulic acid. In-vitro protein denaturation assay of ft-ext showed a potent anti-inflammatory effect. The ft-ext improved ACR-mediated locomotor deficit and reduced overall mortality in the larvae. The brain lipid peroxidation and protein carbonylation results revealed an elevated level of oxidative stress in the ACR-treated group, which was reduced in ft-ext-treated larvae. The extract treatment increased the expression of nrf2, gpx, and hmox1a, while simultaneously downregulated trxr2 levels in the brain of larvae exposed to ACR. The treatment also showed inactivation of Gsk-3β, thus maintaining a normal pool of Nrf2 and β-catenin. Molecular docking of identified compounds of ft-ext showed possible hydrogen and hydrophobic interactions with Gsk-3β.

CONCLUSION

The ft-ext prevents ACR-mediated neurotoxicity by suppressing Gsk-3β mediated oxidative stress.

Chemically-induced epileptic seizures in zebrafish: A systematic review

The use of zebrafish as a model organism is gaining evidence in the field of epilepsy as it may help to understand the mechanisms underlying epileptic seizures. As zebrafish assays became popular, the heterogeneity between protocols increased, making it hard to choose a standard protocol to conduct research while also impairing the comparison of results between studies. We conducted a systematic review to comprehensively profile the chemically-induced seizure models in zebrafish. Literature searches were performed in PubMed, Scopus, and Web of Science, followed by a two-step screening process based on inclusion/exclusion criteria. Qualitative data were extracted, and a sample of 100 studies was randomly selected for risk of bias assessment. Out of the 1058 studies identified after removing duplicates, 201 met the inclusion criteria. We found that the most common chemoconvulsants used in the reviewed studies were pentylenetetrazole (n = 180), kainic acid (n = 11), and pilocarpine (n = 10), which increase seizure severity in a dose-dependent manner. The main outcomes assessed were seizure scores and locomotion. Significant variability between the protocols was observed for administration route, duration of exposure, and dose/concentration. Of the studies subjected to risk of bias assessment, most were rated as low risk of bias for selective reporting (94%), baseline characteristics of the animals (67%), and blinded outcome assessment (54%). Randomization procedures and incomplete data were rated unclear in 81% and 68% of the studies, respectively. None of the studies reported the sample size calculation. Overall, these findings underscore the need for improved methodological and reporting practices to enhance the reproducibility and reliability of zebrafish models for studying epilepsy. Our study offers a comprehensive overview of the current state of chemically-induced seizure models in zebrafish, highlighting the common chemoconvulsants used and the variability in protocol parameters. This may be particularly valuable to researchers interested in understanding the underlying mechanisms of epileptic seizures and screening potential drug candidates in zebrafish models.

Effect of Duvelisib, a Selective PI3K Inhibitor on Seizure Activity in Pentylenetetrazole-Induced Convulsions Animal Model

Epilepsy is one of the most common neurological diseases, which is caused by abnormal brain activity. A wide variety of studies have shown the importance of the phosphatidylinositol-3-kinase (PI3K) signaling pathway in epilepsy pathogenesis. Duvelisib (DUV) is a selective inhibitor of PI3K. The present study investigated the anticonvulsant potential of DUV in a rat model of pentylenetetrazole (PTZ)-induced convulsions. Male Wistar rats (200-250 g, 8 weeks old) were injected intraperitoneally (IP) with DUV at different doses of 5 and 10 mg/kg, or vehicle 30 minutes prior to PTZ (70 mg/kg, IP) treatment. Based on Racine's scale, behavioral seizures were assessed. The results showed that pretreatment with DUV prolonged the seizure stages according to the Racine scale, significantly decreased the duration of general tonic-clonic seizure and reduced the number of myoclonic jerks (P < .05). In conclusion, we found that PI3K antagonist DUV significantly reduced PTZ-induced seizures, indicating that DUV exerts an anticonvulsant effect by inhibiting PI3K signaling pathway.

Zebrafish as a robust preclinical platform for screening plant-derived drugs with anticonvulsant properties-a review

Traditionally, selected plant sources have been explored for medicines to treat convulsions. This continues today, especially in countries with low-income rates and poor medical systems. However, in the low-income countries, plant extracts and isolated drugs are in high demand due to their good safety profiles. Preclinical studies on animal models of seizures/epilepsy have revealed the anticonvulsant and/or antiepileptogenic properties of, at least some, herb preparations or plant metabolites. Still, there is a significant number of plants known in traditional medicine that exert anticonvulsant activity but have not been evaluated on animal models. Zebrafish is recognized as a suitable in vivo model of epilepsy research and is increasingly used as a screening platform. In this review, the results of selected preclinical studies are summarized to provide credible information for the future development of effective screening methods for plant-derived antiseizure/antiepileptic therapeutics using zebrafish models. We compared zebrafish vs. rodent data to show the translational value of the former in epilepsy research. We also surveyed caveats in methodology. Finally, we proposed a pipeline for screening new anticonvulsant plant-derived drugs in zebrafish ("from tank to bedside and back again").

Zebrafish as an Innovative Tool for Epilepsy Modeling: State of the Art and Potential Future Directions

This article discusses the potential of Zebrafish (ZF) (Danio Rerio), as a model for epilepsy research. Epilepsy is a neurological disorder affecting both children and adults, and many aspects of this disease are still poorly understood. In vivo and in vitro models derived from rodents are the most widely used for studying both epilepsy pathophysiology and novel drug treatments. However, researchers have recently obtained several valuable insights into these two fields of investigation by studying ZF. Despite the relatively simple brain structure of these animals, researchers can collect large amounts of data in a much shorter period and at lower costs compared to classical rodent models. This is particularly useful when a large number of candidate antiseizure drugs need to be screened, and ethical issues are minimized. In ZF, seizures have been induced through a variety of chemoconvulsants, primarily pentylenetetrazol (PTZ), kainic acid (KA), and pilocarpine. Furthermore, ZF can be easily genetically modified to test specific aspects of monogenic forms of human epilepsy, as well as to discover potential convulsive phenotypes in monogenic mutants. The article reports on the state-of-the-art and potential new fields of application of ZF research, including its potential role in revealing epileptogenic mechanisms, rather than merely assessing iatrogenic acute seizure modulation.

Developing Novel Experimental Models of m-TORopathic Epilepsy and Related Neuropathologies: Translational Insights from Zebrafish

The mammalian target of rapamycin (mTOR) is an important molecular regulator of cell growth and proliferation. Brain mTOR activity plays a crucial role in synaptic plasticity, cell development, migration and proliferation, as well as memory storage, protein synthesis, autophagy, ion channel expression and axonal regeneration. Aberrant mTOR signaling causes a diverse group of neurological disorders, termed 'mTORopathies'. Typically arising from mutations within the mTOR signaling pathway, these disorders are characterized by cortical malformations and other neuromorphological abnormalities that usually co-occur with severe, often treatment-resistant, epilepsy. Here, we discuss recent advances and current challenges in developing experimental models of mTOR-dependent epilepsy and other related mTORopathies, including using zebrafish models for studying these disorders, as well as outline future directions of research in this field.

Insights into the Cellular Interactions and Molecular Mechanisms of Ketogenic Diet for Comprehensive Management of Epilepsy

A high-fat diet with appropriate protein and low carbohydrate content, widely known as the ketogenic diet (KD), is considered as an effective non-pharmacotherapeutic treatment option for certain types of epilepsies. Several preclinical and clinical studies have been carried out to elucidate its mechanism of antiepileptic action. Ketone bodies produced after KD's breakdown interact with cellular excito-inhibitory processes and inhibit abnormal neuronal firing. The generated ketone bodies decrease glutamate release by inhibiting the vesicular glutamate transporter 1 and alter the transmembrane potential by hyperpolarization. Apart from their effect on the well-known pathogenic mechanisms of epilepsy, some recent studies have shown the interaction of KD metabolites with novel neuronal targets, particularly adenosine receptors, adenosine triphosphate-sensitive potassium channel, mammalian target of rapamycin, histone deacetylase, hydroxycarboxylic acid receptors, and the NLR family pyrin domain containing 3 inflammasomes to suppress seizures. The role of KD in augmenting gut microbiota as a potential mechanism for epileptic seizure suppression has been established. Furthermore, some recent findings also support the beneficial effect of KD against epilepsy- associated comorbidities. Despite several advantages of the KD in epilepsy management, its use is also associated with a wide range of side effects. Hypoglycemia, excessive ketosis, acidosis, renal stones, cardiomyopathies, and other metabolic disturbances are the primary adverse effects observed with the use of KD. However, in some recent studies, modified KD has been tested with lesser side effects and better tolerability. The present review discusses the molecular mechanism of KD and its role in managing epilepsy and its associated comorbidities.

R-α-Lipoic Acid Conjugated to d-α-Tocopherol Polyethylene Glycol 1000 Succinate: Synthesis, Characterization, and Effect on Antiseizure Activity

α-Lipoic acid (LA), a dithiol micronutrient, acts as a vital cofactor in various cellular catabolic reactions and is also known as a universal antioxidant. The therapeutic efficacy of LA is compromised by a poor aqueous solubility as well as a short half-life. In the present study, LA was conjugated to d-α-tocopherol polyethylene glycol succinate (TPGS) using carbodiimideacid-alcohol coupling reaction. The synthesized conjugate (TPGS-LA) was characterized using ¹H and ¹³C nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR), UV-vis spectroscopy, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The TPGS-LA conjugate was demonstrated to be biocompatible and to have better anticonvulsion activity as compared to native LA in pentylenetetrazol (PTZ)-induced convulsions in zebrafish. Moreover, zebrafish larvae pretreated with TPGS-LA conjugate demonstrated a significant (p < 0.05) reduction of protein carbonylation levels and downregulation of c-fos expression during seizures as compared to native LA. Conclusively, the present findings demonstrate that the TPGS-LA conjugate can be a promising approach for the delivery of LA.

Optimization of a locomotion-based zebrafish seizure model

BACKGROUND

Locomotor assays in zebrafish have emerged as a screening test in early drug discovery for antiseizure compounds. However, parameters differ considerably between published studies, which may explain some discrepant results with (candidate) antiseizure medications.

NEW METHOD

We optimized a locomotor-based seizure assay in zebrafish with pentylenetetrazol (PTZ) as the pharmacological proconvulsant to generate a therapeutic window in which proconvulsant-treated zebrafish larvae could be discriminated from a non-treated control. To generate a reliable control, exposure time and concentration of valproate (VPA, anticonvulsant) was optimized.

RESULTS

Wells with one or three larvae show a similar PTZ dose-dependent increase in locomotion with less variability in motility for the latter. Zebrafish immersed in 10 mM PTZ showed a significant increase in movement with a sustained effect, without any indication of toxicity. Animals treated with 3 mM VPA showed the strongest reduction of PTZ-induced movement without toxicity. The decrease in PTZ-induced locomotion was greater after 18 h versus 2 h.

COMPARISON WITH EXISTING METHOD(S)

For the larval zebrafish PTZ-induced seizure model, varying experimental parameters have been reported in literature. Our results show that PTZ is often used at toxic concentrations, and we provide instead reliable conditions to quantify convulsant behaviour using an infrared-beam motility assay.

CONCLUSIONS

We recommend using three zebrafish larvae per well to quantify locomotion in 96-multiwell plates. Larvae should preferably be exposed to 10 mM PTZ for 1 h, consisting of 30 min acclimation and 30 min subsequent recording. As positive control for anticonvulsant activity, we recommend exposure to 3 mM VPA for 18 h before administration of PTZ.

GC-MS Profile of Hua-Feng-Dan and RNA-Seq Analysis of Induced Adaptive Responses in the Liver

Background: Hua-Feng-Dan is a patent Chinese medicine for stroke recovery and various diseases. This study used GC-MS to profile its ingredients and RNA-Seq to analyze the induced adaptive response in the liver. Methods: Hua-Feng-Dan was subjected to steam distillation and solvent extraction, followed by GC-MS analysis. Mice were orally administered Hua-Feng-Dan and its "Guide drug" Yaomu for 7 days. Liver pathology was examined, and total RNA isolated for RNA-Seq, followed by bioinformatic analysis and quantitative real-time PCR (qPCR). Results: Forty-four volatile and fifty liposoluble components in Hua-Feng-Dan were profiled and analyzed by the NIST library and their concentrations quantified. The major components (>1%) in volatile (5) and liposoluble (10) were highlighted. Hua-Feng-Dan and Yaomu at hepatoprotective doses did not produce liver toxicity as evidenced by histopathology and serum enzyme activities. GO Enrichment revealed that Hua-Feng-Dan affected lipid homeostasis, protein folding, and cell adhesion. KEGG showed activated cholesterol metabolism, bile secretion, and PPAR signaling pathways. Differentially expressed genes (DEGs) were identified by DESeq2 with p < 0.05 compared to controls. Hua-Feng-Dan produced more DEGs than Yaomu. qPCR on selected genes largely verified RNA-Seq results. Ingenuity Pathways Analysis of the upstream regulator revealed activation of MAPK and adaptive responses by Hua-Feng-Dan, and Yaomu was less effective. Hua-Feng-Dan-induced DEGs were highly correlated with the Gene Expression Omnibus database of chemical-induced adaptive transcriptome changes in the liver. Conclusion: GC-MS primarily profiled volatile and liposoluble components in Hua-Feng-Dan. Hua-Feng-Dan at the hepatoprotective dose did not produce liver pathological changes but induced metabolic and signaling pathway activations. The effects of Hua-Feng-Dan on liver transcriptome changes point toward induced adaptive responses to program the liver to produce hepatoprotective effects.

Progesterone attenuates neurological deficits and exerts a protective effect on damaged axons via the PI3K/AKT/mTOR-dependent pathway in a mouse model of intracerebral hemorrhage

Intracerebral hemorrhage (ICH) is a devastating event with high disability and fatality rates. However, there is a lack of effective treatments for this condition. We aimed to investigate the neuroprotective and axonal regenerative effects of progesterone after ICH. For this purpose, an ICH model was established in adult mice by injecting type VII collagenase into the striatum; the mice were then treated with progesterone (8 mg/kg). Hematoma absorption, neurological scores, and brain water content were evaluated on days one, three, and seven after the ICH. The effect of progesterone on inflammation and axonal regeneration was examined on day three after the ICH using western blotting, immunohistochemistry, immunofluorescence, as well as hematoxylin-eosin, Nissl, and Luxol fast blue staining. In addition, we combined progesterone with the phosphoinositide 3-kinase/serine/threonine-specific protein kinase (PI3K/AKT) inhibitor, LY294002, to explore its potential neuroprotective mechanisms. Administration of progesterone attenuated the neurological deficits and expression of inflammatory cytokines and promoted axonal regeneration after ICH, this effect was blocked by LY294002. Collectively, these results suggest that progesterone could reduce axonal damage and produced partial neuroprotective effects after ICH through the PI3K/AKT/mTOR pathway, providing a new therapeutic target and basis for the treatment of ICH.

Recombinant human erythropoietin protects long-term cultured ageing primary nerve cells by upregulating the PI3K/Akt pathway

OBJECTIVE

Previous studies have found that recombinant human erythropoietin (rhEPO) protects long-term cultured ageing primary nerve cells by enhancing the endogenous antioxidant capacity of cells; however, its signalling pathways are not clear. This study aimed to explore the relationship between the rhEPO and PI3K/Akt pathways in the protection of senescent nerve cells at the cellular level.

METHODS

Primary nerve cells were cultured for 22 days to mimic the natural ageing process of nerve cells. rhEPO and LY294002 were administered as an intervention on the 11th day of culture. Western blot, immunochemistry, 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide, immunofluorescence double-labelling staining, Annexin V-FITC/PI double-labelling flow cytometry, and SA-β-gal staining experiments were used to observe the expression levels of erythropoietin receptor (EPOR) and phosphorylated Akt (p-Akt) protein and the related indices of nerve cell senescence.

RESULTS

Western blot experiments showed that in ageing long-term cultured primary neurons, the EPOR and p-Akt decreased and rhEPO upregulated the expression levels of EPOR and p-Akt protein. The rest showed that the PI3K/Akt pathway blockade reduced the antioxidation capacity, cell viability, cell morphology, and ratio of apoptotic cells and senescent cells of rhEPO on ageing long-term cultured primary nerve cells.

CONCLUSIONS

This study explored the relationship between the rhEPO and PI3K/Akt pathways in the protection of ageing nerve cells at the cellular level and found that rhEPO protects long-term cultured ageing primary nerve cells by upregulating the PI3K/Akt pathway. These findings provide a theoretical basis and experimental evidence for the antiaeging mechanism of EPO in the nervous system.

Anti-seizure effects of medicinal plants in Malawi on pentylenetetrazole-induced seizures in zebrafish larvae

ETHNOPHARMACOLOGICAL RELEVANCE

Medicinal plants are used to manage and treat epilepsy in Malawi because of traditional beliefs and barriers to conventional anti-seizure drugs. Among the plants prescribed by traditional medical practitioners are Margaritaria discoidea, Dalbergia boehmii, Dalbergia nitidula, Catunaregam spinosa, and Lannea discolor. Despite the wide use of these plants, there is a lack of scientific evidence to support their anti-seizure efficacy.

AIM OF THE STUDY

This study used the pentylenetetrazole (PTZ)-induced larval zebrafish seizure model to screen for anti-seizure effects of a collection of medicinal plants traditionally used in Malawi.

MATERIALS AND METHODS

Zebrafish larvae were incubated in decoctions at maximum tolerated concentrations for 18 h and exposed to PTZ. As a primary screen, the effects of the decoctions on seizure-induced locomotor activity were determined. Decoctions that significantly reduced total distance traveled were further checked for effects on seizure latency and frequency, brain activity, immediate early gene expression, and c-fos protein expression.

RESULTS

M. discoidea male leaves, D. boehmii roots, and D. nitidula leaves showed significant anti-seizure effects in the primary screen and were selected for further study. Electrophysiological and immediate early gene analyses corroborated anti-seizure effect of D. boehmii and D. nitidula. The results of c-fos protein expression further suggested that the anti-seizure effects in the larval brain may be mediated by the suppression of neurons localized in midbrain regions.

CONCLUSIONS

These findings provide pioneering scientific evidence of the presence of anti-seizure activity in M. discoidea, D. boehmii, and D. nitidula, prescribed by traditional Malawian medical practitioners. Further studies are needed to identify and isolate compounds responsible for such biological activities and elucidate the possible mechanisms of action.

Zebrafish as an experimental model for the simulation of neurological and craniofacial disorders

Zebrafish have gained momentum as a leading experimental model in recent years. At present, the zebrafish vertebrate model is increasingly used due to its multifactorial similarities to humans that include genetic, organ, and cellular factors. With the emergence of novel research techniques that are very expensive, it is necessary to develop affordable and valid experimental models. This review aimed to highlight some of the most important similarities between zebrafish and humans by emphasizing the relevance of the first in simulating neurological disorders and craniofacial deformity.

Amelioration of cognitive deficit in zebrafish by an undescribed anthraquinone from Juglans regia L.: An in-silico, in-vitro and in-vivo approach

An undescribed anthraquinone assigned as 1-Hydroxy-5,5-dimethyl-5,6,7,8-tetrahydro-9,10-anthraquinone (compound 1) was isolated from ethylacetate extract of Juglans regia L. The structure of the compound was established on the basis of 1D, 2D NMR (HSQC, HMBC, COSY), ESI-QTOF-MS/MS spectroscopy. The molecular docking studies of compound 1 indicated similar molecular interactions as that of co-crystalized inhibitor. Compound 1 showed hydrogen bonds with residues PHE295, GLY121, π-σ interactions with TYR 341, π-π interactions with HIS 447 residues, and π-alkyl with TRP86 and TYR 337. On the basis of in-silico interaction studies of compound 1 with proteins, it was tested using acetylcholinesterase inhibition assay, acrylamide-induced neurotoxicity test of zebrafish larva, and scopolamine-induced cognitive deficit model of adult zebrafish. The compound 1 showed potent acetylcholinesterase inhibition activity, prevented acrylamide-induced neurotoxicity and improved learning and memory functions in T-maze test. The results established compound 1 to be a potential neuroprotective natural product for amelioration of cognitive impairment.

Hesperidin Interacts With CREB-BDNF Signaling Pathway to Suppress Pentylenetetrazole-Induced Convulsions in Zebrafish

Hesperidin (3,5,7-trihydroxyflavanone 7-rhamnoglucoside) is a β-7-rutinoside of hesperetin (4'-methoxy-3',5,7-trihydroxyflavanone), abundantly found in citrus fruits and known to interact with various cellular pathways to show a variety of pharmacological effects. The present study was envisaged to understand the anticonvulsant effect of hesperidin in a zebrafish model of pentylenetetrazole (PTZ)-induced convulsions, with the support of in silico docking. Healthy zebrafish larvae were preincubated with hesperidin (1, 5, and 10 µM) for 1 h, before PTZ exposure. Hesperidin treatment significantly increased the seizure latency and minimized PTZ-induced hyperactive responses. A significant reduction in c-fos expression further supported the suppression of neuronal excitation following hesperidin incubation in the larvae exposed to PTZ. The treatment also modulated larval bdnf expression and reduced the expression of il-10. The results of in vivo studies were further supported by in silico docking analysis, which showed the affinity of hesperidin for the N-methyl-d-aspartate receptor, the gamma-aminobutyric acid receptor, Interleukin 10 and the TrkB receptor of brain-derived neurotrophic factor. The results concluded that hesperidin suppresses PTZ-mediated seizure in zebrafish larvae through interaction with the central CREB-BDNF pathway.

Deciphering key regulators involved in epilepsy-induced cardiac damage through whole transcriptome and proteome analysis in a rat model

OBJECTIVE

Sudden unexpected death in epilepsy (SUDEP) is a major outcome of cardiac dysfunction in patients with epilepsy. In continuation of our previous work, the present study was envisaged to explore the key regulators responsible for cardiac damage associated with chronic seizures using whole transcriptome and proteome analysis in a rat model of temporal lobe epilepsy.

METHODS

A standard lithium-pilocarpine protocol was used to induce recurrent seizures in rats. The isolated rat heart tissue was subjected to transcriptomic and proteomic analysis. An integrated approach of RNA-Seq, proteomics, and system biology analysis was used to identify key regulators involved in seizure-linked cardiac changes. The analyzed differential expression patterns and network interactions were supported by gene and protein expression studies.

RESULTS

Altogether, 1157 differentially expressed genes and 1264 proteins were identified in the cardiac tissue of epileptic animals through RNA-Seq and liquid chromatography with tandem mass spectrometry-based proteomic analysis, respectively. The network analysis revealed seven critical genes-STAT3, Myc, Fos, Erbb2, Erbb3, Notch1, and Mapk8-that could play a role in seizure-mediated cardiac changes. The LC-MS/MS analysis supported the activation of the transforming growth factor β (TGF-β) pathway in the heart of epileptic animals. Furthermore, our gene and protein expression studies established a key role of STAT3, Erbb, and Mapk8 to develop cardiac changes linked with recurrent seizures.

SIGNIFICANCE

The present multi-omics study identified STAT3, Mapk8, and Erbb as key regulators involved in seizure-associated cardiac changes. It provided a deeper understanding of molecular, cellular, and network-level operations of the identified regulators that lead to cardiac changes in epilepsy.

Development and validation of chemical kindling in adult zebrafish: A simple and improved chronic model for screening of antiepileptic agents

BACKGROUND

Zebrafish has emerged as a potential animal model of acute convulsion for early screening of antiepileptic agents. There is a need for alternative chronic zebrafish models of epilepsy with more correlation to the clinical condition.

NEW METHOD

Adult zebrafish were repeatedly exposed to subeffective concentrations of pentylenetetrazole (PTZ), until appearance to tonic-clonic seizures, considered as kindled. Valproic acid (VPA) exposure was given during kindling and in kindled fish in 2 different groups. The neurotransmitters level and expression of the genes associated with kindling were studied in the fish brain.

RESULTS

There was an increase in seizure severity score at 1.25 mM concentration of PTZ, and 66.66 % of fish achieved kindling after 22 days' exposure. A marked increase in c-fos, crebbpa and crebbpbexpression, and glutamate/GABA level was observed in the brain of kindled fish. VPA inhibited the induction of PTZ-mediated kindling and reduced seizure severity in kindled fish.

COMPARISON WITH EXISTING METHOD

In contrast to an existing adult zebrafish kindling method, the present protocol is of longer duration, with more similarity to clinical epilepsy. Moreover, the induction of kindling involves a simple non-invasive technique without the use of anesthesia. The protocol can be used for evaluation of both antiepileptic and antiepileptogenic agents.

CONCLUSION

Repeated exposure of 1.25 mM PTZ induced kindling in zebrafish, altering the brain neurotransmitter levels and gene expression. Inhibition of kindling induction and decrease in seizures in normal and kindled fish, respectively by VPA validated application of the model for preclinical testing of agents against epilepsy.