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

Prelievo di liquido cerebrospinale e sangue dai ratti con registrazione EEG concomitante

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.

Autore in primo piano: Ottenere campioni di sangue e CSF di alta qualità per la scoperta di biomarcatori dell'epilessia 

Campionamento del liquido cerebrospinale e del sangue dalla vena caudale laterale nei ratti durante le registrazioni 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  

Video-EEG legato nei ratti epilettici per l'analisi dell'attività convulsiva

Per iniziare, metti l'animale in una gabbia pulita nella sala di registrazione per consentire l'assuefazione al nuovo ambiente. Posizionare la gabbia in una gabbia di Faraday per evitare interferenze del campo elettromagnetico ambientale nel segnale EEG. Collegare un'estremità del cavo di registrazione al dispositivo di registrazione.Utilizzare un voltmetro per misurare il potenziale elettrico e per distinguere tra elettrodi di terra e di riferimento. Quindi tieni la copertura di cemento sulla testa dell'animale e inserisci l'altra estremità del cavo di registrazione nel connettore dell'elettrodo fissato sulla testa del ratto. Utilizzare un commutatore per controbilanciare il peso del cavo di registrazione e per consentire il libero movimento dell'animale senza attorcigliare il cavo.Prima di iniziare la registrazione, verificare tutte le impostazioni utilizzate per l'acquisizione e l'elaborazione dei dati dall'EEG. Assicurarsi che vengano applicati filtri e frequenze di campionamento adeguati per evitare artefatti e disturbi nei segnali EEG. Avviare la registrazione video e le registrazioni EEG sul monitor.Controllare la potenza in bande di frequenza specifiche nel tempo per assicurarsi che le tracce corrispondano a un segnale EEG previsto. Controllare periodicamente i tracciati EEG. Inoltre, controlla gli animali.Se un cavo di registrazione si stacca dal connettore dell'elettrodo, ricollegarlo e verificare che il segnale EEG sia chiaro. Analizza il segnale EEG eseguendo lo screening attraverso la registrazione EEG e identifica le attività simili alle convulsioni. Confermare le potenziali convulsioni controllando la registrazione video sincronizzata raccolta contemporaneamente all'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 ...

Ricerca

Neuroscienze

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

Raccolta di sangue dalla vena caudale dei ratti durante le registrazioni EEG

Collection of Cerebrospinal Fluid from Rat Cisterna Magna During EEG Recordings

Raccolta di liquido cerebrospinale da Cisterna Magna di ratto durante le registrazioni EEG