Implantation of Electroencephalogram and Electrocardiogram Telemetry Devices in Neonatal Rabbit Kits

Summary

Mechanisms of sudden unexpected death in epilepsy (SUDEP) are poorly understood and challenging to translate from current models. Transgenic rabbits may offer insights into these mechanisms. We describe a method for long-term, continuous electroencephalography and electrocardiography recordings in transgenic rabbit kits to evaluate serious events that may lead to death.

Abstract

Pathogenic variants in ion channel genes are associated with a high rate of sudden unexpected death in epilepsy (SUDEP). Mechanisms of SUDEP are poorly understood but may involve autonomic dysfunction and cardiac arrhythmias in addition to seizures. Some ion-channel genes are expressed in both the brain and the heart, potentially increasing the risk of SUDEP in patients with ion-channelopathies associated with epilepsy and cardiac arrhythmias. Transgenic rabbits expressing epilepsy variants provide a whole organism to study the complex physiology of SUDEP. Importantly, rabbits more closely replicate human cardiac physiology than do mouse models. However, rabbit models have additional health and anesthesia considerations when undergoing invasive monitoring procedures. We have developed a novel method to surgically implant a telemetry device for long-term simultaneous electroencephalogram (EEG) and electrocardiogram (ECG) monitoring in neonatal rabbit kits. Here, we demonstrate surgical methods to implant a telemetry device in P14 (weight range 175-250 g) kits with detailed attention to surgical approach, appropriate anesthesia and monitoring, and postoperative care, resulting in a low complication rate. This method allows for continuous monitoring of neural and cardiac electrophysiology during critical points in the development of cardiac arrhythmias, seizures, and potential SUDEP in rabbit models of genetic or acquired epilepsies.

Introduction

Sudden unexpected death in epilepsy (SUDEP) is a leading cause of death in patients with epilepsy. Mechanisms of SUDEP are poorly understood but potentially involve autonomic dysfunction, apnea, and cardiac arrhythmias in addition to seizures^{1,2,3,4,5,6,7}. Patients with channelopathy-linked genetic epilepsies have among the highest rates of SUDEP. For example, SUDEP occurs in up to 20% of patients with variants in the voltage-gated sodium....

Protocol

All work described was reviewed and approved by the University of Michigan Institutional Animal Care and Use Committee as part of an approved animal use protocol and is in line with relevant federal laws and guidelines, including the USDA Animal Welfare Act and NIH Public Health Service Policy. The University of Michigan is an AAALACi-accredited institution.

1. Animal preparation

1. Rough-shave kits (age P14-P19, weight >175 g) 1-2 days prior to the procedure to minimize anesthesia time on the day of surgery using clippers.
2. Autoclave or gas sterilize all surgical tools and materials (as possible) in p....

Discussion

The protocol described for anesthetic induction, monitoring, and support balances research needs for surgical approach and ease with gold standards of veterinary care. Prior to the laboratory adopting the described protocol as standard procedure, several other potential refinements were trialed, including dorsal subcutaneous implant placement, the use of an endotracheal tube or laryngeal mask airway, and the use of an esophageal stethoscope attachment for heart rate monitoring. However, all were ultimately abandoned for .......

Materials

Name	Company	Catalog Number	Comments
1 inch elastic wrap - Coban or Vetwrap	3M	https://www.3m.com/3M/en_US/p/d/b00003186/
4-0 PDS monofilament suture	Ethicon	https://www.jnjmedtech.com/en-US/company/ethicon/all-products
5-0 Ethilon nylon suture	Ethicon	https://www.jnjmedtech.com/en-US/company/ethicon/all-products
Acquisition computer	Dell	https://www.dell.com/en-us
Adhesive surgical towels	N/A	N/A
Anesthesia circuit - Jackson-Reevs with 0.5 L rebreathing bag	JorVet	J0248GA
Betadine scrub	N/A	N/A
Bupivicaine (0.5%)	N/A	N/A	Diluted to 2.5 mg/mL prior to administration
Buprenorphine (0.3 mg/mL)	N/A	N/A	Diluted to 0.03 mg/mL prior to administration
Burr - 1.00 mm	Cell Point Scientific	60-1000	to drill skull
Cafazolin (1 g lypholized)	N/A	N/A	Diluted to 50 mg/mL
Carprofen (50 mg/mL)	MWI Veterinary		Diluted to 25 mg/mL prior to administration
Cotton tipped applicators	N/A	N/A
Custom 3-D printed face mask	N/A	https://www.thingiverse.com/thing:923725
Dental acrylic	N/A	N/A
Diet Gel Criticare	Clear H2O	72-05-5042	Nutritional support
Dopper Gel - Aquasonic	Patterson	07-890-5542
Doppler - Vet-Dop2	Patterson	07-888-8986
Doxapram (20 mg/mL)	MWI Veterinary	N/A	Emergency only
Dumont #5 Fine Forceps	Fine Science Tools	11254-20	For holding screws
Duraprep	3M	8630	Final skin prep
ecgAuto data analysis software	emka technologies	N/A
Epinephrine (1:1000)	MWI Veterinary	N/A	Emergency only
Gauze	N/A	N/A
Glucometer ipet Pro	MWI Veterinary	63867	Monitor if poor recovery
Glycopyrrolate (0.2 mg/mL)	MWI Veterinary	N/A	Emergency only
Gram scale	N/A	N/A
Hemostats	Fine Science Tools	13008-12	Hold wire loops while tying the loop in place
Ideal Micro-drill	Cell Point Scientific	67-1204	To drill skull
Incubator	DRE-veterinary (Infantia - NB1)	N/A
Induction box	VetEquip	941444
Infared heating pad - RightTemp Jr	Kent Scientific Corporation	RT-0502
IOX2 data acquisition software	emka technologies	N/A
IV Catheter - Covidein Monoject 26 G, 3/4 inch PTFE	Patterson	07-836-8494
ketamine (100 mg/mL)	MWI Veterinary	N/A
Medical tape	N/A	N/A
Narrow Pattern Forceps - Straight/12 cm	Fine Science Tools	11002-12
Neonatal stethescope	Ultrascope	N/A
Olsen-Hegar Needle holder with scissors - 12 cm	Fine Science Tools	12002-12	For suturing
Ophthalmic ointment Puralube	MWI Veterinary	N/A	Administered to both eyes during anesthesia
Opthalmic Lubricant - Paralube Vet	Patterson	07-888-2572
Pulse oximeter (AccuWave Portable )	Patterson	07-892-9128	For prep and recovery; reads HR up to 400
Pulse oximeter (SDI - Vet/Ox plus 4700)	Heska	N/A	Intra-operative; no longer producted
Receiver	emka technologies	N/A	1 receiver for every 4 telemetry implants
Rectal thermometer	N/A	N/A
Scalpel	Fine Science Tools	10003-12
Scissors	Fine Science Tools	14002-12	To cut drape
Screw driver - 1.0 mm	N/A	N/A	From mini-screwdriver set for electronics
Screws 00-96 x 3/32 (2.4 mm)	Protech International	8L0X3905202F
Sevoflurane	MWI Veterinary		Maintenance anesthesia
Sevoflurane vaporizer and anesthesia machine	N/A	N/A
Skin glue, Gluture	MWI Veterinary	34207	Apply sparingly with syringe
Small scissors	Fine Science Tools	14084-08
Sterile aluminum foil	N/A	N/A	To wrap wires prior to rotating animal
Sterile paint brush	N/A	N/A	To apply dental acrylic
Sterile Saline	N/A	N/A
Sterile surgical gloves	N/A	N/A
Sterile ultrasound cover	N/A	N/A	To cover the drill
Sterile Water	N/A	N/A	For cefazolin reconstitution
Surgical blade no. 15	N/A	N/A
Surgical drape	N/A	N/A
Surgical gown	N/A	N/A
Swivel connector - Jorgensen Labs	Patterson	07-802-2349	To connect anesthesia circuit to face mask
Telemetry implant	emka technologies	easyTEL+_M1_EETA_B_35
Trocar	SAI	TRO-10-6	To tunnel wires