Experiment 1: A total of 48 adult Wistar rats were untreated for 7 minutes after induction of VF using an external transthoracic alternating current, and subsequent CPR was performed to observe the existence of autophagy after the return of spontaneous circulation (ROSC). Experiment 2: A total of 72 rats were pretreated with intracerebroventricular injection of physiologic saline (control group), the autophagy inducer (rapamycin group), or the autophagy inhibitor 3-methyladenine (3-methyladenine group) before ROSC to evaluate the contribution of autophagy to neuronal injury after ROSC.
The activation of autophagy was attenuated 2 to 4 hours after ROSC, which was related to the activity decrease of 5′-adenosine monophosphate–activated protein kinase after ROSC. Rapamycin treatment significantly increased the expressions of LC3-II and Beclin-1 after ROSC, attenuated the activation of caspase-3, promoted neuronal survival and decreased neuronal apoptosis, and improved the neurologic deficit score after CPR.
The activation of autophagy after ROSC offered a remarkable tolerance to VF/CPR ischemic insult and improved the neurologic outcomes.