2.2 Mouse model of CA/CPR
CA/CPR model in mice was performed as previously described with minor
modifications (Fig. 1A) [28]. In brief, mice were anesthetized,
endotracheally intubated with a 22 G cannula and connected to a mouse
ventilator. Normothermia was maintained during the surgery. Internal
jugular venous catheters were placed for drug delivery.
Electrocardiogram (ECG) was monitored with subcutaneous needle
electrodes throughout the surgical procedure. After 5-min stabilization,
CA was induced by intravenous administration of KCL (50 µL, 0.5 M) and
was defined as the appearance of isoelectric tracing on ECG monitor.
During CA, the ventilator was disconnected and pericranial temperature
was maintained at 38.5 ± 0.2 ◦C.
CPR was initiated at the end of 10-min CA by mechanical ventilation with
100% oxygen, injection of epinephrine (0.5 mL, 16 µg/mL) and finger
chest compressions at a rate of 300 compressions per minute. Return of
spontaneous circulation (ROSC) was defined as stable spontaneous
electrical activity on ECG. Mice failed to ROSC within 3.5 min were
excluded from the continuing experiments. Once spontaneous respiration
was confirmed, mice were extubated and surgical wounds were sutured. At
the end of each experimental period, mice were placed in their cages
with easily accessible food and water.