To sum up, our study provides the first evidence that Gn-Rb1 protects against post-cardiac arrest myocardial stunning, partly via alleviating oxidative stress and mitochondrial destabilization through the activation of the Keap1/Nrf2 signaling pathway, which sheds insight into the role of Gn-Rb1 as a new prospective agent against CA. Here, KEAP1 is linked to cardiac arrest.