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

Extracción de líquido cefalorraquídeo y sangre de ratas con registro de EEG concurrente

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.

Autor destacado: Obtención de muestras de sangre y LCR de alta calidad para el descubrimiento de biomarcadores de epilepsia 

Toma de muestras de líquido cefalorraquídeo y sangre de la vena lateral de la cola en ratas durante los registros de 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 atado en ratas epilépticas para el análisis de la actividad convulsiva

Para comenzar, coloque al animal en una jaula limpia en la sala de grabación para permitir que se habitúe al nuevo entorno. Coloque la jaula en una jaula de Faraday para evitar la interferencia del campo electromagnético ambiental en la señal de EEG. Conecte un extremo del cable de grabación al dispositivo de grabación.Utilice un voltímetro para medir el potencial eléctrico y diferenciar entre electrodos de tierra y de referencia. Luego sostenga la cubierta de cemento en la cabeza del animal e inserte el otro extremo del cable de grabación en el conector del electrodo fijado en la cabeza de la rata. Utilice un conmutador para contrarrestar el peso del cable de grabación y permitir el libre movimiento del animal sin torcer el cable.Antes de iniciar el registro, verifique todos los ajustes utilizados para adquirir y procesar los datos del EEG. Asegúrese de que se apliquen las frecuencias de filtrado y muestreo adecuadas para evitar artefactos y ruido en las señales de EEG. Inicie la grabación de video y las grabaciones de EEG en el monitor.Verifique la potencia en bandas de frecuencia específicas a lo largo del tiempo para asegurarse de que los rastros coincidan con una señal de EEG esperada. Revise los rastros de EEG periódicamente. Además, revisa a los animales.Si un cable de grabación se separa del conector del electrodo, vuelva a conectarlo y verifique si hay una señal de EEG clara. Analice la señal del EEG mediante el cribado a través del registro del EEG e identifique las actividades similares a las convulsiones. Confirme las posibles convulsiones comprobando la grabación de vídeo sincronizada recogida simultáneamente con el 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 ...

Investigación

Neurociencias

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

Recolección de sangre de la vena de la cola de ratas durante los registros de EEG

Collection of Cerebrospinal Fluid from Rat Cisterna Magna During EEG Recordings

Recolección de líquido cefalorraquídeo de rata Cisterna Magna durante registros de EEG