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.