Mouse Cardiac Arrest Model for Brain Imaging and Brain Physiology Monitoring During Ischemia and Resuscitation

Summary

This protocol demonstrates a unique mouse model of asphyxia cardiac arrest that does not require chest compression for resuscitation. This model is useful for monitoring and imaging the dynamics of brain physiology during cardiac arrest and resuscitation.

Abstract

Most cardiac arrest (CA) survivors experience varying degrees of neurologic deficits. To understand the mechanisms that underpin CA-induced brain injury and, subsequently, develop effective treatments, experimental CA research is essential. To this end, a few mouse CA models have been established. In most of these models, the mice are placed in the supine position in order to perform chest compression for cardiopulmonary resuscitation (CPR). However, this resuscitation procedure makes the real-time imaging/monitoring of brain physiology during CA and resuscitation challenging. To obtain such critical knowledge, the present protocol presents a mouse asphyxia CA model that does not require the chest compression CPR step. This model allows for the study of dynamic changes in blood flow, vascular structure, electrical potentials, and brain tissue oxygen from the pre-CA baseline to early post-CA reperfusion. Importantly, this model applies to aged mice. Thus, this mouse CA model is expected to be a critical tool for deciphering the impact of CA on brain physiology.

Introduction

Cardiac arrest (CA) remains a global public health crisis¹. More than 356,000 out-of-hospital and 290,000 in-hospital CA cases are reported annually in the US alone, and most CA victims are over 60 years old. Notably, post-CA neurologic impairments are common among survivors, and these represent a major challenge for CA management^2,3,4,5. To understand post-CA brain pathologic changes and their effects on neurologic outcomes, various neurophysiologic monitoring and brain tissue monitoring techniq....

Protocol

All the procedures described here were conducted in accordance with the National Institutes of Health (NIH) guidelines for the care and use of animals in research, and the protocol was approved by the Duke Institute of Animal Care and Use Committee (IACUC). C57BL/6 male and female mice aged 8-10 weeks old were used for the present study.

1. Surgical preparation

1. Weigh a mouse on a digital scale, and place it into a 4 in x 4 in x 7 in plexiglass anesthesia induc.......

Discussion

In experimental CA studies, asphyxia, potassium chloride injections, or electrical current-derived ventricular fibrillation have been used to induce CA^{16,17,18,19,20,21,22,23}. Normally, CPR is required for resuscitation in these CA models, especially in mic.......

Materials

Name	Company	Catalog Number	Comments
Adrenalin	Par Pharmaceutical	NDC 42023-159-01
Alcohol swabs	BD	326895
Animal Bio Amp	ADInstruments	FE232
BP transducer	ADInstruments	MLT0699
Bridge Amp	ADInstruments	FE117
Heparin sodium injection, USP	Fresenius Kabi	NDC 63323-540-05
Isoflurane	Covetrus	NDC 11695-6777-2
Laser Doppler perfusion monitor	Moor Instruments	moorVMS-LDF1
Laser speckle imaging system	RWD	RFLSI III
Lubricant eye ointment	Bausch + Lomb	339081
Micro clip	Roboz	RS-5431
Mouse rectal probe	Physitemp	RET-3
Needle electrode	ADInstruments	MLA1213	29 Ga, 1.5 mm socket
Nitrogen	Airgas	UN1066
Optic plastic fibre	Moor Instruments	POF500
Otoscope	Welchallyn	728	2.5 mm Speculum
Oxygen	Airgas	UN1072
PE-10 tubing	BD	427401	Polyethylene tubing
Povidone-iodine	CVS	955338
PowerLab 8/35	ADInstruments
Rimadyl (carprofen)	Zoetis	6100701	Injectable 50 mg/ml
Small animal ventilator	Kent Scientific	RoVent Jr.
Temperature controller	Physitemp	TCAT-2DF
Triple antibioric & pain relief	CVS	NDC 59770-823-56
Vaporizer	RWD	R583S
0.25% bupivacaine	Hospira	NDC 0409-1159-18
0.9% sodium chroride	ICU Medical	NDC 0990-7983-03
1 mL plastic syringe	BD	309659
4-0 silk suture	Look	SP116	Black braided silk
6-0 nylon suture	Ethilon	1698G
8.4% sodium bicarbonate Inj., USP	Hospira	NDC 0409-6625-02
20 G IV catheter	BD	381534	20GA 1.6 IN
30 G PrecisionGlide needle	BD	305106	30 G X 1/2