Cardioprotection of CAPE- o NO 2 against myocardial ischemia/reperfusion induced ROS generation via regulating the SIRT1/eNOS/NF-κB pathway in vivo and in vitro

Abstract Caffeic acid phenethyl ester (CAPE) could ameliorate myocardial ischemia/reperfusion injury (MIRI) by various mechanisms, but there hadn’t been any reports on that CAPE could regulate silent information regulator 1 (SIRT1) and endothelial nitric oxide synthase (eNOS) to exert cardioprotective effect. The present study aimed to investigate the cardioprotective potential of caffeic acid o -nitro phenethyl ester (CAPE- o NO 2 ) on MIRI and the possible mechanism based on the positive control of CAPE. The SD rats were subjected to left coronary artery ischemia /reperfusion (IR) and the H9c2 cell cultured in hypoxia/reoxygenation (HR) to induce the MIRI model. Prior to the procedure, vehicle, CAPE or CAPE- o NO 2 were treated in the absence or presence of a SIRT1 inhibitor nicotinamide (NAM) and an eNOS inhibitor Nω-nitro- L -arginine methyl ester (L-NAME). In vivo , CAPE and CAPE- o NO 2 conferred a cardioprotective effect as shown by reduced myocardial infarct size, cardiac marker enzymes and structural abnormalities. From immunohistochemical and sirius red staining, above two compounds ameliorated the TNF-α release and collagen deposition of IR rat hearts. They could agitate SIRT1 and eNOS expression, and consequently enhance NO release and suppress NF-κB signaling, to reduce the malondialdehyde content and cell necrosis. In vitro , they could inhibit HR-induced H9c2 cell apoptosis and ROS generation by activating SIRT1/eNOS pathway and inhabiting NF-κB expression. Emphatically, CAPE- o NO 2 presented the stronger cardioprotection than CAPE both in vivo and in vitro. However, NAM and L-NAME eliminated the CAPE- o NO 2 -mediated cardioprotection by restraining SIRT1 and eNOS expression, respectively. It suggested that CAPE- o NO 2 ameliorated MIRI by suppressing the oxidative stress, inflammatory response, fibrosis and necrocytosis via the SIRT1/eNOS/NF-κB pathway.