Name: Tethered Video-EEG in Epileptic Rats for Analyses of Seizure Activity
Uploaded: 2023-09-01T13:40:00
Description: Watch this Scientific Journal Video about Tethered Video-EEG in Epileptic Rats for Analyses of Seizure Activity at JoVE.com

tethered video-eeg in epileptic rats for analyses of seizure activity

Prélèvement de liquide céphalo-rachidien et de sang chez le rat avec enregistrement EEG simultané

Cerebrospinal fluid (CSF) and blood sampling are important to identify and validate biomarkers of epilepsy, in both preclinical and clinical research1,2. Nowadays, the diagnosis of epilepsy and most of the research on epilepsy biomarkers focus on EEG and neuroimaging3,4,5. These approaches, however, present several limitations. Apart from routine scalp measurements, in many cases, EEG requires invasive techniques like depth electrodes6. Brain imaging methods have poor temporal and spatial resolution and are relatively expensive and time-consuming7,8. For this reason, the identification of non-invasive, low-cost, and biofluid-based biomarkers would provide a very attractive alternative. In addition, these biofluid biomarkers could be combined with available diagnostic approaches to sharpen their predictiveness.
Patients diagnosed with epilepsy are routinely submitted to EEG9,10 and blood sampling11,12,13,14, and many also to CSF withdrawal to exclude life-threatening causes (i.e., acute infections, autoimmune encephalitis)15. These blood and CSF samples can be used in clinical research aiming to identify biomarkers for epilepsy. For example, Hogg and co-workers have found that an increase in three plasma tRNA fragments precedes seizure occurrence in human epilepsy14. Similarly, interleukin-1beta (IL-1&#946;) levels in human CSF and serum, expressed as ratio of IL-1&#946; levels in CSF over serum, can predict post-traumatic epilepsy development after traumatic brain injury16. These studies highlight the importance of biofluids sampling for epilepsy biomarkers research, but they face multiple limitations intrinsic to clinical trials, e.g., the cofounding factor of anti-epileptic drugs (AEDs) in blood, the frequent lack of etiology information, inadequate controls, modest numbers of patients, and others17,18.
Pre-clinical research offers other opportunities for investigating molecules in biofluids as potential biomarkers for epilepsy. In fact, it is possible to withdraw plasma and/or CSF from animals while performing EEG recordings. Moreover, sampling can be performed repeatedly across multiple days of the experiment, and a number of age, sex, and epileptic insult-matched controls can be used to improve the study&#39;s robustness. Here, a flexible technique to obtain CSF from cisterna magna with parallel withdrawal of plasma from the tail vein in EEG-monitored rats is described in detail. The presented technique has several advantages over alternative methods. By using a butterfly needle approach, it is possible to collect CSF several times without compromising the function of EEG electrodes or similar head implants. This represents a refinement of intrathecal catheter withdrawal procedures, which are associated with a relatively high risk of infection. In addition, the reported free fall dropping approach used for blood collection is superior to other approaches of tail vein blood withdrawal because of the highly reduced risk of hemolysis, due to the fact that blood does not pass through tubing and no vacuum pressure is applied. If performed under strict germ-free conditions, there is a particularly low risk of infection for animals. In addition, by starting the blood withdrawals at the very end of the animals&#39; tails, sampling can be repeated several times. Such techniques are easy to master and can be applied in many preclinical studies of central nervous system disorders.

Pleins feux sur l’auteur : Obtention d’échantillons de LCR et de sang de haute qualité pour la découverte de biomarqueurs de l’épilepsie 

Prélèvement de liquide céphalorachidien et de sang de la veine caudale latérale chez le rat pendant les enregistrements EEG

In our research, we aim to find diagnostic and prognostic biomarkers for epilepsy. In order to validate them in biological liquids, we compare the levels of specific substances in the cerebrospinal fluid and plasma with the occurrence of spontaneous seizures in rats. Today some small non-coding ribonucleic acids like miRNAs or tRNA fragments have been identified as a circulating biomarker for epilepsy, but their utility as an effective and reliable diagnostic or prognostic tool in epilepsy must be confirmed.different circulating markers for epilepsy, we routinely withdraw plasma and CSF of epileptic rats. While performing EEG recording, student find spontaneous seizures. As we repeat the sampling across multiple days, we can correlate the levels of markers with single seizure occurrence or their cumulative effect.The current challenge is to obtain sufficient volume of high quality samples for the following analytical procedures without inducing stress-provoked seizures in animals caused by their manipulation, which may interfere with the levels of molecules under investigation. There is an urgent unmet medical need to discover biomarkers for people with epilepsy, especially the prognostic and risky ones. Plasma and CSF sampling in parallel to EEG seizure monitoring allow the significant advance to find the suitable marker.Our draw tail vein blood withdrawal technique produces high quality hemolysis-free plasma samples, as it does not require a vacuum or tail milking. Cisterna magna puncture that we use to sample CSF has better sterility and a lower risk of head implant loss in comparison to a cannulated system.

Watch this Scientific Journal Video about Tethered Video-EEG in Epileptic Rats for Analyses of Seizure Activity at JoVE.com

Tethered Video-EEG in Epileptic Rats for Analyses of Seizure Activity  

Vidéo-EEG captif chez des rats épileptiques pour l’analyse de l’activité épileptique

Pour commencer, placez l’animal dans une cage propre dans la salle d’enregistrement pour lui permettre de s’habituer à son nouvel environnement. Placez la cage dans une cage de Faraday pour éviter les interférences du champ électromagnétique environnemental dans le signal EEG. Connectez une extrémité du câble d’enregistrement à l’appareil d’enregistrement.Utilisez un voltmètre pour mesurer le potentiel électrique et faire la différence entre les électrodes de terre et les électrodes de référence. Tenez ensuite le couvercle en ciment sur la tête de l’animal et insérez l’autre extrémité du câble d’enregistrement dans le connecteur d’électrode fixé sur la tête du rat. Utilisez un collecteur pour contrebalancer le poids du câble d’enregistrement et pour permettre à l’animal de se déplacer librement sans tordre le câble.Avant de commencer l’enregistrement, vérifiez tous les paramètres utilisés pour acquérir et traiter les données de l’EEG. Assurez-vous que des taux de filtrage et d’échantillonnage adéquats sont appliqués pour éviter les artefacts et le bruit dans les signaux EEG. Démarrez l’enregistrement vidéo et les enregistrements EEG sur le moniteur.Vérifiez la puissance dans des bandes de fréquences spécifiques au fil du temps pour vous assurer que les traces correspondent à un signal EEG attendu. Vérifiez périodiquement les traces EEG. Vérifiez également les animaux.Si un câble d’enregistrement se détache du connecteur de l’électrode, rebranchez-le et vérifiez que le signal EEG est clair. Analysez le signal EEG en passant au crible l’enregistrement EEG et identifiez les activités semblables à des crises. Confirmez les crises convulsives potentielles en vérifiant l’enregistrement vidéo synchronisé recueilli simultanément avec l’EEG.

Research

JoVE Journal

Neuroscience

Tethered Video-EEG in Epileptic Rats for Analyses of Seizure Activity

Sampling Cerebrospinal Fluid and Blood from Lateral Tail Vein in Rats During EEG Recordings

Because the composition of body fluids reflects many physiological and pathological dynamics, biological liquid samples are commonly obtained in many ...

Recherche

Neurosciences

Collection of Blood from the Tail Vein of Rats During EEG Recordings

Collecte de sang de la veine caudale de rats pendant les enregistrements EEG

Collection of Cerebrospinal Fluid from Rat Cisterna Magna During EEG Recordings

Prélèvement de liquide céphalorachidien de la cisterna magna du rat pendant les enregistrements EEG