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

Cerebrospinalvätska och bloduttag från råttor med samtidig EEG-registrering

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.

Författare i fokus: Erhållande av högkvalitativa CSF- och blodprover för upptäckt av biomarkörer för epilepsi 

Provtagning av cerebrospinalvätska och blod från lateral svansven hos råttor under EEG-inspelningar

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  

Uppbunden video-EEG hos epileptiska råttor för analys av anfallsaktivitet

Börja med att placera djuret i en ren bur i inspelningsrummet för att tillåta tillvänjning till den nya miljön. Placera buren i en Faraday-bur för att undvika störningar av det elektromagnetiska fältet i EEG-signalen. Anslut ena änden av inspelningskabeln till inspelningsenheten.Använd en voltmätare för att mäta den elektriska potentialen och för att skilja mellan jord- och referenselektroder. Håll sedan cementskyddet på djurets huvud och sätt in den andra änden av inspelningskabeln i elektrodkontakten som är fäst på råttans huvud. Använd en kommutator för att balansera vikten på inspelningskabeln och för att tillåta fri rörlighet för djuret utan att vrida kabeln.Innan du påbörjar registreringen, kontrollera alla inställningar som används för att samla in och bearbeta data från EEG. Se till att adekvata filtrerings- och samplingshastigheter tillämpas för att undvika artefakter och brus i EEG-signaler. Starta videoinspelningen och EEG-inspelningarna på monitorn.Kontrollera effekten i specifika frekvensband över tid för att säkerställa att spåren matchar en förväntad EEG-signal. Kontrollera EEG-spåren med jämna mellanrum. Kontrollera också djuren.Om en inspelningskabel lossnar från elektrodkontakten, anslut den igen och kontrollera om det finns en tydlig EEG-signal. Analysera EEG-signalen genom screening genom EEG-registreringen och identifiera anfallsliknande aktiviteter. Bekräfta de potentiella krampanfallen genom att kontrollera den synkroniserade videoinspelningen som samlats in samtidigt med EEG.

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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 ...